Detection of vital germ cell tumor cells in short-term cell cultures of primary tumors and of retroperitoneal metastasis--clinical implications

Abstract

By establishing short-term cell cultures derived from retroperitoneal metastasis after neoadjuvant chemotherapy, our aim was to improve the diagnosis and prognosis in patients with advanced testicular germ cell tumors. The histological evaluation of surgically removed metastatic tissue by retroperitoneal lymphadenectomy (RLA) is extremely complicated after previous chemotherapy, but knowledge of persistence of vital tumor cells in residual lesions is of great prognostic value and therapeutic consequence in patients with testicular germ cell tumors. We therefore investigated whether vital tumor tissue could be detected in short-term cell cultures derived from such metastatic lesions by measuring the concentration of the tumor markers beta human chorionic gonadotropin (beta HCG) and alpha-1 fetoprotein (AFP) in cell culture supernatants. We initially demonstrated the specificity of the determination in cell cultures of human transitional-cell carcinoma cell lines, human foreskin fibroblasts and normal testicular tissue. In a group of 20 patients with untreated primary testicular germ cell tumors, detection of beta HCG and AFP was increased about threefold in cell culture supernatants in comparison to the serum concentration. Finally, we prepared primary cell cultures from surgically removed retroperitoneal metastasis of 12 patients with testicular germ cell tumors after chemotherapy. The serum concentrations of beta HCG and AFP of all patients were at normal values when RLA was performed. However, pathologically increased concentrations of beta HCG (3/3) and AFP (2/3) in cell culture supernatants were found in 3 of 12 cell cultures. Interestingly, these three patients with a pathological increase in beta HCG and AFP as determined in the supernatant of the short-term cell cultures had tumor progression within a mean follow-up of 3 +/- 1 months (P < 0.01), whereas 9 of 12 patients who had no pathological increase in beta HCG and AFP as determined in the supernatant of the short-term cell culture were in complete remission (CR) after a mean follow-up of 40 +/- 11.6 months.