Non-cancer related chromosome translocation frequency measured from a leukemia patient's blood.

A new approach used to measure pre-cancer-induced genetic damage in a patient diagnosed as early B-precursor acute lymphoblastic leukemia, by totally separating the malignant B-lymphocytes and the normal T-lymphocytes 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 exposures. Blood lymphocytes were obtained after diagnosis of the disease, but prior to therapy, and measurements made of (1) the translocation frequency in separated normal T-lymphocytes and (2) the translocation frequency in phytohemagglutinin (PHA) stimulated lymphocytes, which include a fraction of the malignant B cells. The approach described here makes possible biodosimetry of pre-cancer exposures in these patients and may provide the dosimetric information required to establish the "probability of causation" for the observed cancer.