CORRESPONDENCE

Re: Assessment of Plasma DNA Levels, Allelic Imbalance, and CA 125 as Diagnostic Tests for Cancer

Narendra Pisal, Michael Sindos, Albert Singer

Affiliation of authors: N. Pisal, M. Sindos, A. Singer, Department of Women's Health, The Whittington Hospital, London, U.K.

Correspondence to: Narendra Pisal, M.D., M.R.C.O.G., Department of Women's Health, The Whittington Hospital, London N19 5NF, UK (e-mail: pisal{at}dr.com).

We read with interest the article by Chang et al. (1). This article assesses the feasibility of using a novel molecular technique for the early detection of ovarian cancer. The article suggests a very high sensitivity and specificity, making it a very suitable technique as a screening test.

We would like to make the following comments:

  1. Selection of patients with ovarian cancer in this study was retrospective and, therefore, subject to bias. These patients (even those with early-stage ovarian cancers) presumably must have been symptomatic and identified by currently available diagnostic modalities. Hence, detection of these cancers by a new technique does not necessarily imply any improvement over the existing methods. It is also important to establish whether the early cancers in the study had a good outcome, which is expected for ovarian cancers at this stage. We suggest that the researchers could apply this method to asymptomatic women with incidentally diagnosed ovarian cancer, because these women will form the target population for this test.
  2. In addition to tumor stage, age and menopausal status of the patient and histologic grade of the tumor have been shown (2,3) to affect the presence of allelic imbalance. A larger study will help to establish the usefulness of this technique in these subgroups.
  3. Allelic imbalance has been demonstrated in women with endometriosis (4,5). Hence, it is critical to include women with endometriosis in the control population to ensure that there is no overlap. Including such women is even more important, because the level of CA 125 is often elevated in these women.

Chang et al. have correctly pointed out problems regarding the cost and complexity of this technique. However, we agree that this technique is an exciting development and needs further evaluation.

REFERENCES

1 Chang HW, Lee SM, Goodman SN, Singer G, Cho SK, Sokoll LJ, et al. Assessment of plasma DNA levels, allelic imbalance, and CA 125 as diagnostic tests for cancer. J Natl Cancer Inst 2002;94:1697–703.[Abstract/Free Full Text]

2 Pieretti M, Hopenhayn-Rich C, Khattar NH, Cao Y, Huang B, Tucker TC. Heterogeneity of ovarian cancer: relationships among histological group, stage of disease, tumor markers, patient characteristics, and survival. Cancer Invest 2002;20:11–23.[CrossRef][Medline]

3 Pribill I, Speiser P, Leary J, Leodolter S, Hacker NF, Friedlander ML, et al. High frequency of allelic imbalance at regions of chromosome arm 8p in ovarian carcinoma. Cancer Genet Cytogenet 2001;129:23–9.[Medline]

4 Bischoff FZ, Heard M, Simpson JL. Somatic DNA alterations in endometriosis: high frequency of chromosome 17 and p53 loss in late-stage endometriosis. J Reprod Immunol 2002;55:49–64.[CrossRef][Medline]

5 Goumenou AG, Arvanitis DA, Matalliotakis IM, Koumantakis EE, Spandidos DA. Microsatellite DNA assays reveal an allelic imbalance in p16(Ink4), GALT, p53, and APOA2 loci in patients with endometriosis. Fertil Steril 2001;75:160–5.[CrossRef][Medline]



             
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