A positive correlation between T-cell-receptor mutant frequencies and dicentric chromosome frequencies in lymphocytes from radiotherapy patients.

Dose estimates for the assessment of future risks, following accidental exposure to radiation, for certain diseases such as cancer usually rely on both physical and biological quantitative analyses. A traditional biological method of choice is the measurement of chromosome aberration frequencies in peripheral-blood lymphocytes. However, thorough examination of large sample populations is time and labor intensive. Recently, it became possible to measure mutant frequencies in T lymphocytes; one method is a colony assay at the HPRT gene, and the other is a flow-cytometric assay at the T-cell-receptor (TCR) gene. To test for the possible use of these mutation assays, concurrent measurements were taken on blood samples from women who previously received a full course of radiation therapy for gynecological cancer. The results showed that the frequency of TCR mutants correlated reasonably well with that of dicentric chromosomes, whereas the frequency of HPRT mutants did not. Possible uses of the TCR mutation assay in combination with the conventional chromosome analysis or micronucleus assay after exposure of a relatively large population are discussed.