Correspondence to: Armen K. Nersesyan, Ph.D., D.Sc., Laboratory of Carcinogenesis, Cancer Research Center, 76 Fanardjian St., Yerevan 52, Armenia (e-mail: genetik{at}ysu.am).
Bondy et al. (1) recently presented interesting data concerning -radiation sensitivity and the risk of glioma. The conclusion of investigators was that
-radiation-induced mutagen sensitivity of lymphocytes may be associated with an increased risk for glioma. I am not sure of this conclusion because Bondy et al. (1) based their hypothesis on the data showing that
-radiation induced a statistically significantly higher frequency of chromatid breaks in cells of glioma patients than in cells of healthy subjects. It is well known that cancer patients have greater genetic instability and that chromosomal aberrations, micronuclei, and DNA damage levels in somatic cells of cancer patients are higher than those in somatic cells of healthy subjects because of the cancer itself or because of the action of exogenous mutagens (2).
I agree with Shadan and Koziol (3), who proposed that the detection of inherent genome instability, as determined by increased mutagen susceptibility (including radiation susceptibility), may enhance the identification of populations at risk for cancer, including those at risk for glioma. For example, it has been shown that sensitivity to -radiation-induced chromatid breaks in lymphocytes is associated with the risk of breast and colorectal cancers (4,5).
In my opinion, the data concerning cancers induced by -radiation in humans (6) deserve support. The most frequent malignant diseases induced by
-radiation are leukemia and cancers of the thyroid, breast, and lung but not cancers of the brain. Therefore, increased
-radiation sensitivity of chromosomes may show an individual's susceptibility to the four malignant diseases mentioned above. In my opinion, interpretation of the results from Bondy et al. (1) should be deferred until a prospective cohort study of the effects of enhanced sensitivity to radiation can be performed, as I have pointed out recently (7).
REFERENCES
1
Bondy ML, Wang LE, El-Zein R, de Andrade M, Selvan MS, Bruner JM, et al. Gamma-radiation sensitivity and risk of glioma. J Natl Cancer Inst 2001;93:15537.
2
Berwick M, Vineis P. Markers of DNA repair and susceptibility to cancer in humans: an epidemiologic review. J Natl Cancer Inst 2000;92:87497.
3 Shadan FF, Koziol J. Induced genome instability as a potential screening test for cancer susceptibility? Med Hypotheses 2000;55:6972.[Medline]
4 Buchholz TA, Wu X. Radiation-induced chromatid breaks as a predictor of breast cancer risk. Int J Radiat Oncol Biol Phys 2001;49:5337.[Medline]
5 Baria K, Warran C, Roberts SA, West CM, Scott D. Chromosomal radiosensitivity as a marker of predisposition to common cancer? Br J Cancer 2001;84:8926.[Medline]
6 Ron E. Ionizing radiation and cancer risk: evidence from epidemiology. Radiat Res 1998;150(5 Suppl):S3041.[Medline]
7
Nersesyan AK. Re: Benzo[a]pyrene diol epoxide and bleomycin sensitivity and susceptibility to cancer of upper aerodigestive tract. J Natl Cancer Inst 1999;91:13346.
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