RADIOSENSITIVITY OF BLOOD-LYMPHOCYTES FROM BASOCELLULAR CARCINOMA PATIENTS, AS DETECTED BY THE MICRONUCLEUS ASSAY

Cytogenetic techniques, the micronucleus (MN) assay, in particular, ha ve been widely used in population monitoring, biological dosimetry and early detection of groups susceptible to cancer. Individuals respond differently to several environmental agents. The efficiency of the cel lular repair mechanisms would be responsible, at least to some extent, for individual differences in sensitivity to neoplasia. In order to d etermine the sensitivity of cancer patients to ionizing radiation, blo od cultures from untreated individuals with basocellular carcinoma, yo ung healthy subjects and older healthy subjects, were irradiated in vi tro with Co-60 at doses ranging from 0 to 500 cGy and submitted to the cyto-B micronucleus assay; the frequency of cells and distribution of MN and dose-response relationships were analyzed. Results showed that cancer patients had a lower frequency of cells with spontaneous MN th an older healthy subjects. The frequency of micronucleated cells was n ot different in patients and healthy subjects, but not the distributio n of MN per radiation dose: for the carcinoma group, while the proport ion of cells with one MN decreases drastically, the proportion of the cells with two or more MN increases with the same intensity. Our resul ts show that the proportion of damaged cells is similar in patients wi th basocellular carcinoma and healthy subjects, but the magnitude of r adiation-induced lesion is greater in the cancer patients.