MOBILIZATION OF CD34-POSITIVE TUMOR-CELLS IN A PATIENT WITH TESTICULAR MIXED GERM-CELL TUMOR

Tumour cells from a patient with recurrent testicular germ cell cancer and bone marrow infiltration were found to express CD33 and CD34 in t he absence of other haemopoiesis-associated antigens. After myelosuppr ession and treatment with G-CSF for stem cell mobilization, CD34-posit ive tumour cells were detected in the peripheral blood in addition to normal haemopoietic progenitor cells. The tumour cells were decreased in the leukapheresis product. Retrospectively, the appearance of tumou r cells in the peripheral blood after stem cell mobilization was the f irst indication of impending relapse.