NONCANCER RELATED CHROMOSOME-TRANSLOCATION FREQUENCY MEASURED FROM A LEUKEMIA PATIENTS BLOOD

A new approach used to measure pre-cancer-induced genetic damage in a patient diagnosed as early B-precursor acute lymphoblastic leukemia, b y totally separating the malignant B-lymphocytes and the normal T-lymp hocytes is described. The lymphocytes separation by a rosetting method and chromosome translocation analysis using chromosome painting were employed. In the case presented here, the utility of this approach is illustrated using blood lymphocytes from a nuclear dockyard worker who claims that his leukemia was induced by work-related radiation exposu res. Blood lymphocytes were obtained after diagnosis of the disease, b ut prior to therapy, and measurements made of (1) the translocation fr equency in separated normal T-lymphocytes and (2) the translocation fr equency in phytohemagglutinin (PHA) stimulated lymphocytes, which incl ude a fraction of the malignant B cells. The approach described here m akes possible biodosimetry of pre-cancer exposures in these patients a nd may provide the dosimetric information required to establish the '' probability of causation'' for the observed cancer.