Limitations of detection of bone-marrow micrometastasis in prostate carcinoma patients by CK18/PSA immunocytochemistry and PSA RT-PCR

Background: The aim of this study was to prove the reliability of cytokerat in 18/ prostate specific antigen (CK18/PSA) immunocytochemistry to detect t umor cells in the bone marrow of patients with prostate cancer (CaP) compar ed with a control group without CaP. Patients and Methods: In bone marrow a spirates of 34 patients with CaP and 11 control patients without Cap, CK18/ PSA immunocytochemistry was performed and compared with PSA RT-PCR in bone marrow and blood. Results: 12% of tumors showed a positive staining with PS A and and 17% with CK 18 immunocytochemistry. There was no correlation with the stage or grade of the CaP. False positive results occurred in 2 out of 6 males without CaP and in 2 out of 5 women. 35 % of the samples were foun d to have PSA-mRNA signals in RT-PCR which were neither associated with the histological stage or grade nor the PSA staining in immunocytochemistry. C onclusion: False positive staining results were obtained in control patient s. Detection of PSA-mRNA was not associated with immunocytochemistry. Neith er immunocytochemical nor PCR results were associated with the histological stage of the Cap. Thus, detection of micrometastasis using immunocytochemi cal methods has to be interpreted with caution and cannot be recommended as a clinical staging procedure.