Kinetics of peripheral blood CD34-postoperative cells and optimal timing of blood stem cell harvest after urological anticancer chemotherapy

Abstract

(Purpose) We evaluated the changes in stem cells in peripheral blood and the otpimal timing for harvesting peripheral blood stem cells (PBSCs) following the administration of conventional cancer chemotherapy in patients with urological malignancies. (Patients and Methods) We evaluated the changes in PBCs after the administration of cancer chemotherapy in 12 patients with urological malignancies (6 testis cancer, 3 bladder cancer, 3 prostate cancer) using flowcytometric analysis of CD34, a marker of blood stem cell. We evaluated the optimal timing for PBSCs harvesting following the administration of conventional cancer chemotherapy in 6 patients with urological malignancies (2 patients with testis cancer, 3 patients with prostate cancer, 1 patient with bladder cancer) using flowcytometric analysis of CD34 and granulocyte-macrophage colony-forming units (CFU-GM) counts, PBSC samples from 2 patients with prostate cancer were analyzed by the reverse transcriptase-polymerase chain reaction (RT-PCR) method to detect prostate cancer cells. (Results) The percentages of CD34-positive cells tended to increase in the peripheral blood during the period of convalescence that followed the induction of marked myelosupression produced by the cancer chemotherapy. The peak in CD34-positive cells occurred between days 15 and 31 after beginning of cancer chemotherapy. The percentage of CD34-positive cells was increased in the mononuclear cells in harvested PBSCs. The percentages of CD34-positive cells in peripheral blood and in mononuclear cells harvested from PBSCs was correlated with the CFU-GM counts in harvested PBSCs. The CFU- GM counts peaked between days 16 to 31 following cancer chemotherapy. RT-PCR detected prostate-specific antigen (PSA) mRNA expression in PBSCs obtained from 1 of the 2 patients with prostate with prostate cancer. An amount of contamination with PSA mRNA reduced as chemotherapy was repeated. (Conclusion) A sufficient number of PBSCs can be harvested after conventional cancer chemotherapy without the need for special cytotoxic mobilization that may be delayed the patient's treatment. RT-PCR results suggested that the harvested PBSCs should be examined for tumor cell contamination in patients with metastasis in bone marrow. If a sufficient amount of PBSCs will be harvested, the PBSC samples from the patient with bone marrow metastasis after repeated chemotherapy should be used by priority for PBSC transplantation as of today.