DETECTION OF TUMOR-CELLS IN PERIPHERAL-BLOOD SAMPLES FROM PATIENTS WITH GERM-CELL TUMORS USING IMMUNOCYTOCHEMICAL AND REVERSE TRANSCRIPTASE-POLYMERASE CHAIN-REACTION TECHNIQUES

The aim of this study was to establish sensitive techniques for the de tection of residual germ cell tumor cells in peripheral blood and prog enitor cell harvests. For this purpose, we used immunocytochemical sta ining for cytokeratin filaments and reverse transcriptase-polymerase c hain reaction (RT-PCR) for epidermal growth factor receptor (EGF-R) an d germ cell alkaline phosphatase (GCAP), Germ cell tumor lines Tera-1 and Tera-2 were titrated into normal peripheral blood. Immunocytochemi cal staining allowed detection of one cytokeratin-positive tumor cell in 10(5) cells. RT-PCR for EGF-R revealed one tumor cell in 10 cells f or Tera-1 and one tumor cell in 10(3) cells for Tera-2, while RT-PCR f or GCAP displayed a sensitivity of one tumor cell in 10(6) cells for T era-1, one tumor cell in 10(4) cells for Tera-2, and no positivity in normal mononuclear cells (n = 20) and progenitor cell harvests (n = 5) , The analysis of peripheral blood and progenitor cell harvests from 2 0 patients with germ cell tumors revealed tumor cell contamination in three patients using immunocytochemical staining and in seven patients by RT-PCR for GCAP, We conclude that RT-PCR for GCAP appears to be su itable for the sensitive detection of residual germ cell tumor cells i n peripheral blood and progenitor cell harvests.