DETECTION OF GERM-CELL TUMOR-CELLS IN APHERESIS PRODUCTS USING POLYMERASE CHAIN-REACTION

The contamination of apheresis products with tumor cells was evaluated in patients undergoing autologous peripheral blood stem cell transpla ntation for germ cell tumors, A blinded, retrospective analysis was pe rformed on 63 apheresis products from 28 patients using the PCR and pr imers for beta human chorionic gonadotropin (B-HCG). Of the 20 patient s with beta-HCG-secreting tumors, 8 apheresis products from 7 patients were PCR positive, PCR was negative in the 8 patients whose tumors di d not secrete beta-HCG. Twenty-two apheresis products from patients wi th lymphoma and breast cancer were negative for beta-HCG expression, E valuating the 20 patients with beta-HCG-secreting tumors, 100% of PCR- positive patients had elevated serum beta-HCG at the time of apheresis compared to 46.2% of PCR-negative patients (P = 0.04), A positive PCR was also associated with a higher serum beta-HCG at diagnosis (P = 0. 03), Patients receiving a PCR-positive product had a higher relapse ra te (85.7 versus 61.5%) and were more likely to have visceral metastasi s (100 versus 61.5%), although the numbers did not reach statistical s ignificance (P = 0.35 and 0.11, respectively), The finding of beta-HCG mRNA in apheresis products strongly suggests the presence of circulat ing tumor cells in a significant number of germ cell patients undergoi ng autologous transplantation. This assay mag be useful in monitoring attempts at tumor cell depletion and in developing improved prognostic models for assessing risk of relapse after transplantation.