False tumor marker surge evoked by peripheral blood stem cell transplantation

Peripheral blood stem cell transplantation (PBSCT) allows multiple intensive chemotherapy treatments and hematopoietic progenitor cell rescues for poor-risk patients with a variety of malignancies. We report false surges of a tumor marker, serum human chorionic gonadotropin (hCG), evoked by PBSCT in the course of chemotherapy for a poor-risk testicular cancer patient. We confirmed that this phenomenon resulted from reinfusion of peripheral blood stem cells (PBSCs) containing hCG at a high concentration, collected when the patient's serum hCG levels were remarkably elevated. This is the first report to demonstrate false tumor marker surges caused by PBSCT. Because a rapid rise in tumor markers may demand an immediate change in the therapeutic strategy, physicians should be aware of the possibility of this phenomenon when treating poor-risk cancer patients whose tumor markers are remarkably elevated at the time of PBSC harvest.