Genetic polymorphisms of p21 are associated with risk of squamous cell carcinoma of the head and neck

Guojun Li 1, Zhensheng Liu 1, Erich M. Sturgis 1, 2, Qiuling Shi 1, Robert M. Chamberlain 1, Margaret R. Spitz 1 and Qingyi Wei 1, *

1 Department of Epidemiology and 2 Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA

* To whom correspondence should be addressed at: Department of Epidemiology, Box 189, The University of Texas, M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA. Tel: +1 713 792 3020; Fax: +1 713 563 0999; Email: qwei{at}mdanderson.org


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The p21 (Waf1/Cip1/CDKN1A) protein regulates the transition from the G1 to the S phase and has an important role in modulating cell-cycle control, apoptosis and cell growth. Two polymorphisms of the p21 gene at codon 31 (p21 C98A, dbSNP rs1801270) and at the 3' untranslated region (p21 T70C, dbSNP rs1059234) may have an effect on the protein function and may thus play a role in the development of cancer. We hypothesized that these two p21 polymorphisms are associated with the risk of squamous cell carcinoma of the head and neck (SCCHN). We tested this hypothesis in a hospital-based case–control study of 712 patients newly diagnosed with SCCHN and 1222 cancer-free controls who were frequency-matched by age, sex and ethnicity. All subjects were non-Hispanic whites. Our results showed that the variant alleles and genotypes were more common among cases than among controls (P < 0.001 and P = 0.013 for p21C70T, and P < 0.001 and P = 0.035 for p21C98A, respectively). Compared with the p21 70CC genotype, there was a significantly greater risk of SCCHN associated with the variant p21 70TC [odds ratio (OR) = 1.47, 95% confidence interval (CI) = 1.12–1.93] and combined p21 70TC/TT (OR = 1.49, 95% CI = 1.14–1.95) genotypes. Similarly, compared with the p21 98CC genotype, there was also a significantly greater SCCHN risk associated with the variant p21 98AC (OR = 1.32, 95% CI = 1.00–1.73) and combined p21 98AC/AA (OR = 1.37, 95% CI = 1.05–1.79) genotypes. When these two polymorphisms were evaluated together by the number of risk alleles, there was a significant increase in SCCHN risk that was dependent on the number of risk alleles (Ptrend = 0.001). Our results suggest that the presence of these two p21 polymorphisms may be a marker of genetic susceptibility to SCCHN.

Abbreviations: bp, base pairs; CDK, cyclin-dependent kinase; CI, confidence interval; OR, odds ratio; PCR, polymerase chain reaction; SCCHN, squamous cell carcinoma of the head and neck


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Squamous cell carcinomas of the head and neck (SCCHN), which include cancers of the oral cavity, pharynx and larynx, are common worldwide (1). Although smoking and alcohol use have a major role in the etiology of SCCHN (2), only a fraction of smokers and drinkers develops SCCHN. This suggests that host factors, such as variants in genes involved in carcinogen metabolism, DNA repair and cell-cycle control, may contribute to inter-individual variation in susceptibility to SCCHN (38). Cell-cycle checkpoints are crucial for genetic integrity, as cell-cycle arrest allows cells the time needed to repair DNA damage and replication errors. Aberrant cell-cycle control can cause tumor growth by disrupting the balance between normal growth and terminal differentiation.

Cyclin-dependent kinases (CDKs) form complexes with cyclins to modulate cell proliferation through cell-cycle control, whereas CDK inhibitors inhibit the kinase activities of the complexes and block cell-cycle transitions (911). Alterations in genes involved in cell-cycle control frequently result in deregulated cellular proliferation, as evidenced by the fact that genes associated with the regulation of the G1 checkpoint are frequently altered in cancer cells (12). Although no major susceptibility genes for SCCHN have been identified, gains and losses at several loci and altered expression of p53 and DNA repair genes in SCCHN tumors suggest the involvement of altered oncogenes and tumor suppressor genes in the development of SCCHN (13,14). In addition, abnormalities in genes that regulate cell proliferation not only alter cell-cycle control but also disturb DNA repair activities, especially those mediated by p53 in response to DNA damage (15,16).

The p21 (also known as Waf1/Cip1/CDKN1A) protein is a CDK inhibitor that is essential for cellular growth, differentiation and apoptosis (17). p21, a putative tumor suppressor gene, is located on chromosome 6p21.2 and encodes a 21-kDa protein (18) that belongs to the CIP/KIP family, which includes p27 (17) and p57 (19,20). The CIP/KIP proteins share some common sequence motifs that mediate interaction between CDK inhibitors and cyclin-CDK complexes (21,22). The expression of p21 itself is upregulated by p53 in response to DNA damage, leading to either cell-cycle arrest at the G1 checkpoint or apoptosis (17). p21 expression can suppress tumor growth by inhibiting PCNA-dependent DNA replication and mismatch repair in vitro (23,24), and increased expression of p21 and the accompanying reduction in overall CDK activity are associated with cell differentiation (25). Somatic mutations in the p21 gene are rare in human malignancies (26), but reduced p21 expression in tumors has been associated with poor prognosis in humans (2729), including patients with laryngeal SCC (29). It is, therefore, likely that genetic variants in p21 may modulate its expression and thereby affect carcinogenesis.

A total of 40 polymorphisms of p21 have been identified (available at http://egp.gs.washington.edu) (30), of which 35 are intronic. Only seven have an allele frequency >10%, but they are ~1.3 kb upstream of exon 2. One common single-nucleotide polymorphism (SNP), p21 C98A, is found in exon 2, which causes a non-synonymous serine-to-arginine substitution at codon 31. Four single-nucleotide polymorphisms are found within the 3' untranslated region; only one of which, p21C70T, has an allele frequency >10% and causes a single C-to-T substitution 20 nt downstream of the stop codon at exon 3 (Figure 1). Therefore, p21 C98A and p21C70T are thought to alter p21 function.



View larger version (8K):
[in this window]
[in a new window]
 
Fig. 1. p21 gene structure and the positions of all 40 known single-nucleotide polymorphisms (SNPs; http://egp.gs.washington.edu/data/cdkn1a/). UTR, untranslated region; E, exon; CDS, coding DNA sequence.

 
Several epidemiologic studies have examined the effects of p21 polymorphisms on the risk of different types of cancer, but the results are conflicting (3137). Among these studies, only a single small study investigated the effects of p21 C98A and p21C70T on SCCHN risk (31). We previously showed that polymorphisms of genes involved in cell-cycle control, such as p27 and p73, are associated with the risk of lung cancer and SCCHN among non-Hispanic whites (7,38,39). We, therefore hypothesized that polymorphisms of p21 may also contribute to the risk of SCCHN. In this study, we evaluated the association between p21 C98A and p21C70T and risk of SCCHN in a large, ongoing hospital-based, case–control study of SCCHN.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Study population
The detailed methods of this case–control study have been described elsewhere (7,37,38,40). Briefly, all patients had newly diagnosed, untreated SCCHN that was histologically confirmed at The University of Texas M. D. Anderson Cancer Center between May 1995 and October 2003. Approximately 95% of eligible patients who were contacted chose to participate. Patients with second SCCHN primary tumors, primary tumors of the nasopharynx or sinonasal tract, primary tumors outside the upper aerodigestive tract, cervical metastases of unknown origin or histopathologic diagnoses other than squamous cell carcinoma were excluded. The 712 non-Hispanic white patients with primary tumors included in the analysis had cancers of the oral cavity (n = 220; 31%), oropharynx (n = 321; 45%), hypopharynx (n = 36; 5%) and larynx (n = 135; 19%).

The controls included two groups of cancer-free subjects. One group was 605 healthy controls who were selected from a control pool of enrollees at the Kelsey–Seybold Clinic, a multi-specialty physician practice (MPP) with multiple clinics throughout the Houston metropolitan area for an ongoing lung cancer study (39,40). The recruitment of this control group targeted current and former smokers, and the overall response rate was ~75%. Therefore, the MPP controls provided older male former and current smokers for our frequency matching purpose. The other controls were 617 healthy visitors who were accompanying cancer patients to the outpatient clinics at M. D. Anderson Cancer Center (MDACC) but genetically unrelated to the cases (7,38). The response rate for this MDACC control group was ~80%. We had first surveyed the potential control subjects with a short questionnaire to determine their willingness to participate in research studies and to obtain information about their demographic factors. Both control groups had no previous history of any cancer and were not on therapies or treatment for any diseases and were frequency matched to the cases on age (±5 years), gender, ethnicity and smoking status (current, former or never). After informed consent was obtained, blood samples were collected from all study subjects. The research protocol was approved by the M. D. Anderson Cancer Center and Kelsey–Seybold institutional review boards.

Genotyping
We extracted genomic DNA from the buffy-coat fraction of the blood samples using a DNA Blood Mini Kit (Qiagen, Valencia, CA) according to the manufacturer's instructions. We typed for the p21 C98A and p21C70T genotypes by polymerase chain reaction (PCR) and restriction digestion using published primers and a modification of a previously published method (31,41). We performed the PCR analysis with a PTC-200 DNA Engine Peltier thermal cycler (MJ Research, Waltham, MA) in 10 µl of PCR mixture. The PCR mixture contained ~20 ng of genomic DNA, 0.1 mM dNTPs, 1x PCR buffer (50 mM KCl, 10 mM Tris–HCl and 0.1% Triton X-100), 1.5 mM MgCl2, 0.5 U of Taq polymerase (Sigma-Aldrich, St Louis, MO) and 2 pmol of each primer. The amplification conditions were 5 min of initial denaturation at 95°C; 35 cycles of 30 s at 95°C, 35 s at 55°C and 45 s at 72°C; and a final 5-min extension step at 72°C. The conditions were the same for both genotypes except that 30 cycles of 30 s at 59°C (annealing) and 30 s at 72°C (extension) were used for p21C70T. PCR products [496 base pairs (bp) for p21 C98A and 298 bp for p21C70T] were digested with the restriction enzymes BsmAI (for p21 C98A) or PstI (for p21C70T) (New England Biolabs, Beverly, MA) overnight at 55°C (for BsmAI) or 37°C (for PstI) and separated with 3% Metaphor gel containing ethidium bromide. The genotype of p21 C98A was identified by an A allele with fragment lengths of 77, 92 and 238 bp and a C allele with fragment lengths of 92, 165 and 238 bp. The genotype of p21C70T was identified by a T allele with a fragment length of 298 bp and a C allele with fragment lengths of 173 and 125 bp. We performed the PCRs and evaluated the results without knowing the subjects' case or control status. At least 10% of the random samples were retested, and the results were 100% concordant.

Statistical analysis
We analyzed all data using SAS software (version 8e; SAS Institute, Cary, NC). We first used the {chi}2 test to evaluate the differences between cases and controls in the distributions of selected demographic variables, smoking status, alcohol consumption and p21 genotype frequencies. We then estimated the association between the p21 genotype and the risk for SCCHN by computing the odds ratios (ORs) and their 95% confidence intervals (CIs) in both univariate and multivariate logistic regression analyses. For multivariate logistic regression analysis, the p21 genotype was also recoded as a dummy variable. We further stratified the genotype data by subgroups of age, sex, smoking, alcohol drinking and tumor site and assessed any trend in risk with multivariate logistic regression models. Because the two polymorphisms are not in complete linkage disequilibrium, we also evaluated the association between SCCHN risk and the combined genotypes of these two polymorphisms. Logistic regression was also used to assess potential interaction effects by evaluating departures from the models of additive and multiplicative interactions between the two polymorphisms and age, sex, smoking or alcohol use. A more-than-additive interaction was suggested when OR11 > OR10 + OR01 – 1, where OR11 = OR when both factors were present, OR10 = OR when only factor 1 was present, and OR01 = OR when only factor 2 was present. A more-than-multiplicative interaction was suggested when OR11 > OR10 x OR01.


    Results
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The distributions of demographic variables, smoking status, and alcohol drinking for the cases and controls are summarized in Table I. Genotyping of four DNA samples from the cases and seven DNA samples from the controls failed on repeated experiments, so the final analysis included 712 cases and 1222 controls (605 MPP and 617 M. D. Anderson controls). All study subjects were non-Hispanic whites. The comparison between the MPP controls and the MDACC controls showed that the MPP controls tended to be older ever smokers and the MDACC controls tended to be young never smokers as we expected from our frequency-matching design (Table I). As a result, either of the control groups alone would not be an appropriate control group. Because we wished to increase the study power and to minimize any possible selection bias in terms of unknown confounders, we used the combined control group in the final analysis. When the two groups were combined, there were no significant differences in the distributions of age and sex between the cases and controls (P = 0.552 for age and P = 0.572 for sex). The median age was 57 years for the cases (mean = 57 years, range = 18–90 years) and 58 years for the controls (mean = 57.1 years, range = 20–87 years). However, the frequency matching by smoking status was inadequate. There were more current smokers and current drinkers among the cases than among the controls, and these differences were statistically significant (P < 0.001 for both smoking and drinking status). Apparently, current smoker subjects were less likely to participate as controls in the study, which made our frequency matching inadequate, indicating that further adjustment for age, sex, smoking status and alcohol use in multivariate analysis was needed.


View this table:
[in this window]
[in a new window]
 
Table I. Frequency distribution of selected variables among SCCHN patients and controls

 
Then we evaluated whether the two control groups had different genotype distributions that might impact the estimated risk (Table II). Although the p21 C70T and p21 C98A genotype distributions for the MDACC controls were not in agreement with the Hardy-Weinberg equilibrium (P = 0.08 and 0.02, respectively), the distribution for the MPP and combined controls were in agreement with the Hardy–Weinberg equilibrium (P = 0.616 and 0.515 for the MPP controls and P = 0.445 and 0.315 for combined controls, respectively). The departure from the Hardy–Weinberg equilibrium among the MDACC controls could reflect the fact that the subjects were not population-based or random samples from the general population. The risk may, therefore, be overestimated for the heterozygous genotypes when using the MDACC controls as the reference as well as for homozygous genotypes when using the MPP controls as the reference (Table II). Therefore, selection bias could exist for both control groups, so we considered it appropriate to use the combined controls as the reference in order to have larger study power and generate more conservative risk estimates.


View this table:
[in this window]
[in a new window]
 
Table II. p21genotype and allele frequencies of the cases and controls and their association with risk of SCCHN

 
When we used the combined controls as the reference, the p21 98A and p21 70T variant allele frequencies were the same among the cases (0.09 for both variant alleles) and controls (0.06 for both variant alleles), and the differences between the cases and the controls were statistically significant (P = 0.0005 for the p21 98A allele and P = 0.0005 for the p21 70T allele). For subjects with the p21 C98A polymorphism, the frequencies of the CC, AC and AA genotypes were 84.1, 14.6 and 1.3%, respectively, among the cases and 87.9, 11.5 and 0.6%, respectively, among the controls; this difference was statistically significant (P = 0.035). Similarly, for subjects with the p21 C70T polymorphism, the frequencies of the CC, TC and TT genotypes were 83.7, 15.5 and 0.8%, respectively, among the cases and 88.4, 11.1 and 0.5%, respectively, among the controls; this difference was also statistically significant (P = 0.013) (Table II).

Compared with the p21 98CC genotype, there was a significantly greater SCCHN risk associated with the p21 98AC (adjusted OR = 1.32, 95% CI = 1.00–1.73) and combined p21 98AC/AA (OR = 1.37, 95% CI = 1.05–1.79) genotypes (Table II). Similarly, compared with the p21 70CC genotype, there was a significantly greater SCCHN risk associated with the p21 70TC (OR = 1.47, 95% CI = 1.12–1.93) and combined p21 70TC/TT (OR = 1.49, 95% CI = 1.14–1.95) genotypes. For both p21 C98A and p21 C70T polymorphisms, there appeared to be an ‘allele dose’ effect, i.e. the ORs increased as the number of the variant alleles p21 98A (Ptrend = 0.011) and p21 70T (Ptrend = 0.003) increased (Table II).

We further divided the data into subgroups based on age, sex, smoking status, and alcohol drinking status. We evaluated the SCCHN risk for each subgroup by estimating the ORs associated with the combined p21 98AC/AA and the combined p21 70TC/TT variant genotypes compared with the p21 98CC and p21 70CC genotypes, respectively, with adjustment for the aforementioned variables (Table III). When we used the p21 70CC genotype as the reference, the risk associated with the combined TC/TT variant genotype was more evident for subjects older than 60 years (OR = 1.66, 95% CI = 1.07–2.58), men (OR = 1.68, 95% CI = 1.00–2.85), former (OR = 1.52, 95% CI = 1.01–2.29) and never-smokers (OR = 1.73, 95% CI = 1.06–2.83), former (OR = 1.81, 95% CI = 1.08–3.03) and never-drinkers (OR = 1.72, 95% CI = 1.01–2.93), and subjects with oropharyngeal cancer (OR = 1.59, 95% CI = 1.13–2.24). When we used the p21 98CC genotype as the reference, we did not find any significant association between the combined AC/AA variant genotype and SCCHN risk among any subgroup except former smokers (OR = 1.52, 95% CI = 1.01–2.30) and former drinkers (OR = 1.91, 95% CI = 1.13–3.22). Furthermore, there was no evidence for an interaction between both p21 variant genotypes and age, sex, smoking status, or alcohol use on the risk of SCCHN (data not shown).


View this table:
[in this window]
[in a new window]
 
Table III. Associations and stratification analysis of p21 polymorphisms and SCCHN risk

 
Because both the p21 98A and p21 70T alleles appeared to be associated with increased SCCHN risk, we evaluated their combined effect by grouping the subjects into three categories based on the number of risk alleles each subject possessed. Group 1 subjects had zero or one risk allele of either polymorphism (i.e. genotypes p21 70CC and p21 98CC, or p21 70CC and p21 98AC, or p21 70TC and p21 98CC); group 2 subjects had two risk alleles of either polymorphism (i.e. genotypes p21 70CC and p21 98AA or p21 70TT and p21 98CC or p21 70TC and p21 98AC); and group 3 subjects had three or four risk alleles of either polymorphism (i.e. genotypes p21 70TC and p21 98AA or p21 70TT and p21 98AC or p21 70TT and p21 98AA). As shown in Table IV, the frequencies of the combined genotypes were 84.6%, 13.9%, and 1.5% for groups 1, 2, and 3, respectively, among the cases and 89.0%, 10.5%, and 0.5%, respectively, among the controls; this difference was statistically significant (P = 0.004). Compared with group 1, groups 2 and 3 had a significantly increased risk of SCCHN (adjusted OR = 1.40, 95% CI = 1.05–1.85 for group 2 and 3.66, 1.34–10.0 for group 3; Ptrend = 0.001).


View this table:
[in this window]
[in a new window]
 
Table IV. ORs and 95% CIs for the combined p21C70T and p21C98A polymorphism genotypes associated with SCCHN risk

 

    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
In the present study, we examined the association between the p21 C98A and p21C70T polymorphisms and the risk of SCCHN. To the best of our knowledge, this is the largest study of the role of p21 polymorphisms in the etiology of SCCHN. We observed a nearly 1.5-fold increase in SCCHN risk associated with the combined p21 70TC/70TT variant genotype compared with the p21 70CC genotype and a nearly 1.4-fold increase with the combined p21 98AC/98AA variant genotype compared with the p21 98CC genotype. Although there was no overall departure from HWE of the p21 genotype distribution in the combined controls, the departure observed in the MDACC controls caused reduction in overall risk of SCCHN when we used the combined controls as the reference group, generating more conservative results (Table II).

The increase in risk was more evident among older subjects, men, former and never-smokers, former and never alcohol users, and subjects with oropharyngeal cancer for the p21C70T polymorphism and more pronounced only among former smokers and alcohol users for the p21C98A polymorphism. Moreover, the increase was dependent on the number of risk alleles, suggesting that the risk alleles may have an additive effect on SCCHN risk. Indeed, those who were homozygous for both variant alleles had a ~4-fold increase in risk, although such individuals were relatively uncommon.

It is plausible that p21 polymorphisms might affect cancer risk, as p21 arrests cellular growth to allow DNA repair and is induced by p53 in response to DNA damage caused by exposure to environmental carcinogens (42). However, there is no published evidence to date of any functional relevance of these p21 polymorphisms, and the underlying mechanism by which p21C98A and p21C70T might affect cancer risk is unclear. Nevertheless, our study and others do suggest that these two p21 polymorphisms may have functional significance and are likely to contribute to genetic susceptibility to cancer (34,36,43). For instance, the p21 C98A polymorphism causes a serine-to-arginine substitution in its zinc-finger motif, which could alter the protein's function (33). It is also likely that the p21C70T polymorphism may increase SCCHN risk by altering mRNA stability, thereby affecting intracellular levels of p21 protein. Alternatively, the p21 variant alleles may be functionally relevant or in linkage disequilibrium with other functional variants of p21 or with alleles at other nearby loci. However, this hypothesis remains to be tested.

A number of published studies have examined the effect of p21 polymorphisms on human malignancies, including breast cancer (32,36,42), prostate adenocarcinoma (31), colorectal cancer (44), soft-tissue sarcoma (33), lung cancer (4547), endometrial cancer (48), cervical adenocarcinoma (49), ovarian cancer (50), gastric carcinoma (33), nasopharyngeal carcinoma (37), esophageal cancer (51) and skin cancer (52). However, the results from these studies disagree about the effect of p21 polymorphisms on cancer risk, probably because of factors such as small sample size, inclusion of a single polymorphism, inclusion of different ethnic groups in a single study or inadequate adjustment for confounding factors (53). For instance, the only published SCCHN study examined the association between p21 C98A and p21C70T and SCCHN risk in 42 patients and 110 controls (31) and found p21 polymorphisms in 9.1% of controls (10 of 110) and 21.4 % of SCCHN samples (9 of 42), but the difference was not significant, probably because of the small sample size. In our study, the two p21polymorphisms were found in ~12% of controls and 16% of SCCHN patients; this difference, though smaller than in the former study, was statistically significant because our study had a larger sample size and, therefore, a greater study power.

The allele frequency patterns of p21 polymorphisms also vary greatly between major ethnic groups (53). For example, the frequency of the p21 C98A polymorphism is 9–19% in Caucasians (31,32,36,54), including our study population (12%) and 22–55% in populations of African and Asian origin (48,55). Other studies have shown the A and C allele frequencies of p21C98A to be 0.59 and 0.41, respectively, in an Asian population (48) and 0.09 and 0.91 (47), 0.06 and 0.94 (34), and 0.10 and 0.90 (36) among non-Hispanic whites, similar to the results in our study (0.06 and 0.94). Recent studies have further investigated the association between p21 polymorphisms and cancer risk in Asian populations; for example, the p21C98A polymorphism was not found to be associated with the risk of gastric cancer in Taiwanese subjects (56) or non-Hodgkin's lymphoma in Japanese subjects (57), but a significant association with risk of endometrial cancer was found in Korean women (43).

We found that the SCCHN risk associated with both combined p21 variant genotypes (98AC/AA and 70TC/TT) was greater in patients with cancer of the oropharynx (borderline significant for p21C98A polymorphism) than in those with cancers of the oral cavity, hypopharynx or larynx. This may be because oropharyngeal SCC may have a different etiology in relation to environmental risk factors and genetic susceptibility, or it may be because more cases of oropharyngeal SCC were included in this study. Our experience suggests that among SCCHN sites, oropharyngeal SCC is strongly associated with human papillomavirus type 16, whereas oral cavity cancers are not associated with the virus and laryngeal cancers have a variable association (58). While the risk of tobacco- or alcohol-induced oropharyngeal SCC may be modified by p21 genotype, these genotypes may play an even greater role in oropharyngeal cancers arising in nonsmokers, a group particularly associated with HPV-16. However, these hypotheses also need to be validated in future studies with larger sample sizes.

In conclusion, the p21 polymorphisms p21C98A and p21C70T may have a role in the etiology of SCCHN, particularly in some subgroups. These two polymorphisms appeared to contribute jointly to genetic susceptibility to SCCHN. Because the numbers of observations in some strata of stratification analysis were relatively small, any findings would be best considered as preliminary, and further validation of our findings by larger studies that allow for more rigorous subgroup analysis is warranted. Future studies should also focus on gene–environment and gene–gene interactions among cell-cycle genes such as p27, p53, p73 and MDM2.


    Acknowledgments
 
We thank Margaret Lung and Peggy Schuber for assistance in recruiting the subjects; Li-E Wang, Yawei Qiao, Jianzhong He, Xinli Chen and Kejin Xu for laboratory assistance; Pierrette Lo for scientific editing; and Betty J.Larson and Joanne Sider for manuscript preparation. This study was supported by National Institutes of Health grants ES 11740 and CA 100264 (to Q.W.), CA 97007 (to M.R.S. and W.K.Hong), CA 57730 (to R.M.C.), and CA 16672, ES 07784 and ES 11047 (to M. D. Anderson).

Conflict of Interest Statement: None declared.


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 

  1. Pisani,P., Parkin,D.M., Bray,F. and Ferlay,J. (1999) Estimates of the worldwide mortality from 25 cancers in 1990. Int. J. Cancer, 83, 18–29.[ISI][Medline]
  2. Blot,W.J., McLaughlin,J.K., Winn,D.M., Austin,D.F., Greenberg,R.S. and Preston-Martin,S. (1998) Smoking and drinking in relation to oral and pharyngeal cancer. Cancer Res., 48, 3282–3287.
  3. Cheng,L., Sturgis,E.M., Eicher,S.A., Char,D., Spitz,M.R. and Wei,Q. (1999) Glutathione-S-transferase polymorphisms and risk of squamous-cell carcinoma of the head and neck. Int. J. Cancer, 84, 220–224.[CrossRef][ISI][Medline]
  4. Cheng,L., Eicher,S.A., Guo,Z., Hong,W.K., Spitz,M.R. and Wei,Q. (1998) Reduced DNA repair capacity in head and neck cancer patients. Cancer Epidemiol. Biomarkers Prev., 7, 465–468.[Abstract]
  5. Sturgis,E.M., Castillo,E.J., Li,L., Zheng,R., Eicher,S.A., Clayman,G.L., Strom,S.S., Spitz,M.R. and Wei,Q. (1999) Polymorphisms of DNA repair gene XRCC1 in squamous cell carcinoma of the head and neck. Carcinogenesis, 20, 2125–2129.[Abstract/Free Full Text]
  6. Sturgis,E.M., Zheng,R., Li,L., Castillo,E.J., Eicher,S.A., Chen,M., Strom,S.S., Spitz,M.R. and Wei,Q. (2000) XPD/ERCC2 polymorphisms and risk of head and neck cancer: a case–control analysis. Carcinogenesis, 21, 2219–2223.[Abstract/Free Full Text]
  7. Li,G., Sturgis,E.M., Wang,L.E., Chamberlain,R.M., Amos,C.I., Spitz,M.R., El-Naggar,A.K., Hong,W.K. and Wei,Q. (2004) Association of a p73 exon 2 G4C14-to-A4T14 polymorphism with risk of squamous cell carcinoma of the head and neck. Carcinogenesis, 25, 1911–1916.[Abstract/Free Full Text]
  8. Zheng,Y., Shen,H., Sturgis,E.M., Wang,L.E., Eicher,S.A., Strom,S.S., Frazier,M.L., Spitz,M.R. and Wei,Q. (2001) Cyclin D1 polymorphism and risk for squamous cell carcinoma of the head and neck: a case–control study. Carcinogenesis, 22, 1195–1199.[Abstract/Free Full Text]
  9. Cordon-Cardo,C. (1995) Mutations of cell cycle regulators. Biological and clinical implications for human neoplasia. Am. J. Pathol., 147, 545–560.[Abstract]
  10. Hunter,T. and Pines,J. (1994) Cyclins and cancer. II: cyclin D and CDK inhibitors come of age. Cell, 79, 573–582.[CrossRef][ISI][Medline]
  11. MacLachlan,T.K., Sang,N. and Giordano,A. (1995) Cyclins, cyclin-dependent kinases and cdk inhibitors: implications in cell cycle control and cancer. Crit. Rev. Eukaryot. Gene Expr., 5, 127–156.[ISI][Medline]
  12. Lloyd,R.V., Erickson,L.A., Jin,L., Kulig,E., Qian,X., Cheville,J.C. and Scheithauer,B.W. (1999) p27kip1: a multifunctional cyclin-dependent kinase inhibitor with prognostic significance in human cancers. Am. J. Pathol., 154, 313–323.[Abstract/Free Full Text]
  13. Friedlander,P.L. (2001) Genomic instability in head and neck cancer patients. Head Neck, 23, 683–691.[CrossRef][ISI][Medline]
  14. Gollin,S.M. (2001) Chromosomal alterations in squamous cell carcinomas of the head and neck: window to the biology of disease. Head Neck, 23, 238–253.[CrossRef][ISI][Medline]
  15. Preisler,H.D., Kotelnikov,V.M., LaFollette,S., Taylor,S., Mundle,S., Wood,N., Coon,J.S., Hutchinson,J., Panje,W., Caldarelli,D.D. and Griem,K. (1996) Continued malignant cell proliferation in head and neck tumors during cytotoxic therapy. Clin. Cancer Res., 2, 1453–1460.[Abstract]
  16. Kuropkat,C., Rudolph,P., Frahm,S.O., Parwaresch,R. and Werner,J.A. (1999) Proliferation marker Ki-S11—a prognostic indicator for squamous cell carcinoma of the hypopharynx. Virchows Arch., 435, 590–595.[CrossRef][ISI][Medline]
  17. Xiong,Y., Hannon,G.J., Zhang,H., Casso,D., Kobayashi,R. and Beach,D. (1993) p21 is a universal inhibitor of cyclin kinases. Nature, 366, 701–704.[CrossRef][ISI][Medline]
  18. el-Deiry,W.S., Tokino,T., Velculescu,V.E., Levy,D.B., Parsons,R., Trent,J.M., Lin,D., Mercer,W.E., Kinzler,K.W. and Vogelstein,B. (1993) WAF1, a potential mediator of p53 tumor suppression. Cell, 75, 817–825.[CrossRef][ISI][Medline]
  19. Lee,M.H., Reynisdottir,I. and Massague,J. (1995) Cloning of p57KIP2, a cyclin-dependent kinase inhibitor with unique domain structure and tissue distribution. Genes Dev., 9, 639–649.[Abstract]
  20. Matsuoka,S., Edwards,M.C., Bai,C., Parker,S., Zhang,P., Baldini,A., Harper,J.W. and Elledge,S.J. (1995) p57KIP2, a structurally distinct member of the p21CIP1 Cdk inhibitor family, is a candidate tumor suppressor gene. Genes Dev., 9, 650–662.[Abstract]
  21. Koufos,A., Grundy,P., Morgan,K., Aleck,K.A., Hadro,T., Lampkin,B.C., Kalbakji,A. and Cavenee,W.K. (1989) Familial Wiedemann–Beckwith syndrome and a second Wilms tumor locus both map to 11p15.5. Am. J. Hum. Genet., 44, 711–719.[ISI][Medline]
  22. Hirai,H., Roussel,M.F., Kato,J.Y., Ashmun,R.A. and Sherr,C.J. (1995) Novel INK4 proteins, p19 and p18, are specific inhibitors of the cyclin D-dependent kinases CDK4 and CDK6. Mol. Cell. Biol., 15, 2672–2681.[Abstract]
  23. Li,R., Waga,S., Hannon,G.J., Beach,D. and Stillman,B. (1994) Differential effects by the p21 CDK inhibitor on PCNA-dependent DNA replication and repair. Nature, 371, 534–537.[CrossRef][ISI][Medline]
  24. Waga,S., Hannon,G.J., Beach,D. and Stillman,B. (1994) The p21 inhibitor of cyclin-dependent kinases controls DNA replication by interaction with PCNA. Nature, 369, 574–578.[CrossRef][ISI][Medline]
  25. Moffatt,K.A., Johannes,W.U., Hedlund,T.E. and Miller,G.J. (2001) Growth inhibitory effects of 1alpha, 25-dihydroxyvitamin D(3) are mediated by increased levels of p21 in the prostatic carcinoma cell line ALVA-31. Cancer Res., 61, 7122–7129.[Abstract/Free Full Text]
  26. Roninson,I.B. (2002) Oncogenic functions of tumour suppressor p21(Waf1/Cip1/Sdi1): association with cell senescence and tumour-promoting activities of stromal fibroblasts. Cancer Lett., 179, 1–14.[CrossRef][ISI][Medline]
  27. Jiang,M., Shao,Z.M., Wu,J., Lu,J.S., Yu,L.M., Yuan,J.D., Han,Q.X., Shen,Z.Z. and Fontana,J.A. (1997) p21/waf1/cip1 and mdm-2 expression in breast carcinoma patients as related to prognosis. Int. J. Cancer, 74, 529–534.[CrossRef][ISI][Medline]
  28. Wakasugi,E., Kobayashi,T., Tamaki,Y., Ito,Y., Miyashiro,I., Komoike,Y., Takeda,T., Shin,E., Takatsuka,Y., Kikkawa,N., Monden,T. and Monden,M. (1997) p21(Waf1/Cip1) and p53 protein expression in breast cancer. Am. J. Clin. Pathol., 107, 684–691.[ISI][Medline]
  29. Pruneri,G., Pignataro,L., Carboni,N., Buffa,R., Di Finizio,D., Cesana,B.M. and Neri,A. (1999) Clinical relevance of expression of the CIP/KIP cell-cycle inhibitors p21 and p27 in laryngeal cancer. J. Clin. Oncol., 17, 3150–3159.[Abstract/Free Full Text]
  30. National Institute of Environmental Health Sciences, Environmental Genome Projects. NIEHS SNPS, Dec. 2004.
  31. Facher,E.A., Becich,M.J., Deka,A. and Law,J.C. (1997) Association between human cancer and two polymorphisms occurring together in the p21Waf1/Cip1 cyclin-dependent kinase inhibitor gene. Cancer, 79, 2424–2429.[CrossRef][ISI][Medline]
  32. Lukas,J., Groshen,S., Saffari,B., Niu,N., Reles,A., Wen,W.H., Felix,J., Jones,L.A. Hall,F.L. and Press,M.F. (1997) WAF1/Cip1 gene polymorphism and expression in carcinomas of the breast, ovary, and endometrium. Am. J. Pathol., 150, 167–175.[Abstract]
  33. Mousses,S., Ozcelik,H., Lee,P.D., Malkin,D., Bull,S.B. and Andrulis,I.L. (1995) Two variants of the CIP1/WAF1 gene occur together and are associated with human cancer. Hum. Mol. Genet., 4, 1089–1092.[Abstract]
  34. Kibel,A.S., Suarez,B.K., Belani,J., Oh,J., Webster,R., Brophy-Ebbers,M., Guo,C., Catalona,W.J., Picus,J. and Goodfellow,P.J. (2003) CDKN1A and CDKN1B polymorphisms and risk of advanced prostate carcinoma. Cancer Res., 63, 2033–2036.[Abstract/Free Full Text]
  35. Rodrigues,F.C., Kawasaki-Oyama,R.S., Fo,J.F., Ukuyama,E.E., Antonio,J.R., Bozola,A.R., Romeiro,J.G., Rahal,P. and Tajara,E.H. (2003) Analysis of CDKN1A polymorphisms: markers of cancer susceptibility?. Cancer Genet. Cytogenet., 142, 92–98.[CrossRef][ISI][Medline]
  36. Keshava,C., Frye,B.L., Wolff,M.S., McCanlies,E.C. and Weston,A. (2002) Waf-1 (p21) and p53 polymorphisms in breast cancer. Cancer Epidemiol. Biomarkers Prev., 11, 127–130.[Abstract/Free Full Text]
  37. Tsai,M.H., Chen,W.C. and Tsai,F.J. (2002) Correlation of p21 gene codon 31 polymorphism and TNF-alpha gene polymorphism with nasopharyngeal carcinoma. J. Clin. Lab. Anal., 16, 146–150.[CrossRef][ISI][Medline]
  38. Li,G., Sturgis,E.M., Wang,L.E., Chamberlain,R.M., Spitz,M.R., El-Naggar,A.K., Hong,W.K. and Wei,Q. (2004) Association between the V109G polymorphism of the p27 gene and the risk and progression of oral squamous cell carcinoma. Clin. Cancer Res., 10, 3996–4002.[Abstract/Free Full Text]
  39. Li,G., Wang,L.E., Chamberlain,R.M., Amos,C.I., Spitz,M.R. and Wei,Q. (2004) p73 G4C14-to-A4T14 polymorphism and risk of lung cancer. Cancer Res., 64, 6863–6866.[Abstract/Free Full Text]
  40. Wei,Q., Cheng,L., Amos,C.I., Wang,L.E., Guo,Z., Hong,W.K. and Spitz,M.R. (2000) Repair of tobacco carcinogen-induced DNA adducts and lung cancer risk: a molecular epidemiologic study. J. Natl Cancer Inst., 92, 1764–1772.[Abstract/Free Full Text]
  41. Ralhan,R., Agarwal,S., Mathur,M., Wasylyk,B. and Srivastava,A. (2000) Association between polymorphism in p21(Waf1/Cip1) cyclin-dependent kinase inhibitor gene and human oral cancer. Clin. Cancer Res., 6, 2440–2447.[Abstract/Free Full Text]
  42. Powell,B.L., van Staveren,I.L., Roosken,P., Grieu,F., Berns,E.M. and Iacopetta,B. (2002) Associations between common polymorphisms in TP53 and p21WAF1/Cip1 and phenotypic features of breast cancer. Carcinogenesis, 23, 311–315.[Abstract/Free Full Text]
  43. Roh,J.W., Kim,J.W., Park,N.H., Song,Y.S., Park,I.A., Park,S.Y., Kang,S.B. and Lee,H.P. (2004) p53 and p21 genetic polymorphisms and susceptibility to endometrial cancer. Gynecol. Oncol., 93, 499–505.[CrossRef][ISI][Medline]
  44. Shiohara,M., el-Deiry,W.S., Wada,M., Nakamaki,T., Takeuchi,S., Yang,R., Chen,D.L., Vogelstein,B. and Koeffler,H.P. (1994) Absence of WAF1 mutations in a variety of human malignancies. Blood, 84, 3781–3784.[Abstract/Free Full Text]
  45. Shih,C.M., Lin,P.T., Wang,H.C., Huang,W.C. and Wang,Y.C. (2000) Lack of evidence of association of p21WAF1/CIP1 polymorphism with lung cancer susceptibility and prognosis in Taiwan. Jpn. J. Cancer Res., 91, 9–15.[ISI][Medline]
  46. Sjalander,A., Birgander,R., Rannug,A., Alexandrie,A.K., Tornling,G. and Beckman,G. (1996) Association between the p21 codon 31 A1 (arg) allele and lung cancer. Hum. Hered., 46, 221–225.[ISI][Medline]
  47. Su,L., Liu,G., Zhou,W., Xu,L.L., Miller,D.P., Park,S., Lynch,T.J., Wain,J.C. and Christiani,D.C. (2003) No association between the p21 codon 31 serine-arginine polymorphism and lung cancer risk. Cancer Epidemiol. Biomarkers Prev., 12, 174–175.[Free Full Text]
  48. Hachiya,T., Kuriaki,Y., Ueoka,Y., Nishida,J., Kato,K. and Wake,N. (1999) WAF1 genotype and endometrial cancer susceptibility. Gynecol. Oncol., 72, 187–192.[CrossRef][ISI][Medline]
  49. Roh,J.W., Kim,M.H., Kim,J.W., Park,N.H., Song,Y.S., Kang,S.B. and Lee,H.P. (2001) Polymorphisms in codon 31 of p21 and cervical cancer susceptibility in Korean women. Cancer Lett., 165, 59–62.[CrossRef][ISI][Medline]
  50. Milner,B.J., Brown,I., Gabra,H., Kitchener,H.C., Parkin,D.E. and Haites,N.E. (1999) A protective role for common p21WAF1/Cip1 polymorphisms in human ovarian cancer. Int. J. Oncol., 15, 117–9.[ISI][Medline]
  51. Wu,M.T., Wu,D.C., Hsu,H.K., Kao,E.L., Yang,C.H. and Lee,J.M. (2003) Association between p21 codon 31 polymorphism and esophageal cancer risk in a Taiwanese population. Cancer Lett., 201, 175–180.[CrossRef][ISI][Medline]
  52. Konishi,R., Sakatani,S., Kiyokane,K. and Suzuki,K. (2000) Polymorphisms of p21 cyclin-dependent kinase inhibitor and malignant skin tumors. J. Dermatol. Sci., 24, 177–183.[CrossRef][ISI][Medline]
  53. Birgander,R., Sjalander,A., Saha,N., Spitsyn,V., Beckman,L. and Beckman,G. (1996) The codon 31 polymorphism of the p53-inducible gene p21 shows distinct differences between major ethnic groups. Hum. Hered., 46, 148–154.[CrossRef][ISI][Medline]
  54. Koopmann,J., Maintz,D., Schild,S., Schramm,J., Louis,D.N., Wiestler,O.D. and von Deimling,A. (1995) Multiple polymorphisms, but no mutations, in the WAF1/CIP1 gene in human brain tumours. Br. J. Cancer, 72, 1230–1233.[ISI][Medline]
  55. Watanabe,H., Fukuchi,K., Takagi,Y., Tomoyasu,S., Tsuruoka,N. and Gomi,K. (1995) Molecular analysis of the Cip1/Waf1 (p21) gene in diverse types of human tumors. Biochim. Biophys. Acta, 1263, 275–280.[ISI][Medline]
  56. Wu,M.T., Chen,M.C. and Wu,D.C. (2004) Influences of lifestyle habits and p53 codon 72 and p21 codon 31 polymorphisms on gastric cancer risk in Taiwan. Cancer Lett., 205, 61–68.[CrossRef][ISI][Medline]
  57. Hishida,A., Matsuo,K., Tajima,K., Ogura,M., Kagami,Y., Taji,H., Morishima,Y., Emi,N., Naoe,T. and Hamajima,N. (2004) Polymorphisms of p53 Arg72Pro, p73 G4C14-to-A4T14 at Exon 2 and p21 Ser31Arg and the risk of non-Hodgkin's Lymphoma in Japanese. Leukemia Lymphoma, 45, 957–964.[CrossRef][ISI][Medline]
  58. Dahlstrom,K.R., Adler-Storthz,K., Etzel,C.J., Liu,Z., Dillon,L., El-Naggar,A.K., Spitz,M.R., Schiller,J.T., Wei,Q. and Sturgis,E.M. (2003) Human papillomavirus type 16 infection and squamous cell carcinoma of the head and neck in never-smokers: a matched pair analysis. Clin. Cancer Res., 9, 2620–2626.[Abstract/Free Full Text]
Received February 6, 2005; revised April 8, 2005; accepted April 16, 2005.





This Article
Abstract
Full Text (PDF)
All Versions of this Article:
26/9/1596    most recent
bgi105v1
Alert me when this article is cited
Alert me if a correction is posted
Services
Email this article to a friend
Similar articles in this journal
Similar articles in PubMed
Alert me to new issues of the journal
Add to My Personal Archive
Download to citation manager
Request Permissions
Google Scholar
Articles by Li, G.
Articles by Wei, Q.
PubMed
PubMed Citation
Articles by Li, G.
Articles by Wei, Q.