SOMATIC-CELL MUTATIONS AS A POSSIBLE PREDICTOR OF CANCER RISK

The somatic-mutation theory of carcinogenesis has received strong scie ntific support from results of recent studies on tumor-suppressor gene s, We anticipated that people among the high risk for cancer group, ei ther through exposure to various ionizing radiations or by virtue of u nique genotypes, would also manifest increased frequencies of somatic mutation. This report presents the results of two somatic-mutation ass ays-at the erythrocyte glycophorin A (GPA) and lymphocyte T-cell recep tor (TCR) genes-in various groups at high risk for cancer development, including atomic-bomb survivors, patients with various cancers, patie nts administered Thorotrast, and patients with genetic disorders that make them cancer prone. Although neither the GPA-mutation nor the TCR- mutation assay detects gene mutations directly related to carcinogenes is, increased mutation frequencies were detected by both assays in man y individuals among the highrisk groups and among cancer patients. We have continued to follow up those individuals who show values of about three times higher than those of the control group. Thus, these assay s may prove useful for identifying high-risk cancer groups and for est imating the effects of mutagens. Such information would constitute a v aluable data base for epidemiological studies.