The role of the detection of hematogenous micrometastasis in prostate adenocarcinoma and malignant melanoma by RT-PCR

Recent studies reported the possibility of detecting prostate adenocarcinom a and malignant melanoma cells in peripheral blood using RT-PCR of prostati c specific antigen (PSA), prostatic specific membrane antigen (PSMA) and Ty rosinase mRNAs. The PCR results showed high variability, ranging between 0% and 100% of positivity in patients with advanced disease. Our purpose was to evaluate the presence of tumor marker mRNAs in peripheral blood of prost ate cancer and melanoma patients by means of RT-nested-PCR. We tested 70 an d 36 peripheral blood samples from prostate carcinoma and malignant melanom a patients, respectively. The RT-PCR analysis showed the presence of PSA cD NA in 9 out of 70 (12.9%); PSMA cDNA in 14 out of 70 (20%); and Tyrosinase cDNA in 2 out of 36 (5.5%) peripheral blood samples from melanoma patients. Our study confirms the applicability of this sensitive method to monitor d isease status. Although, the RT-nested-PCR of Tyrosinase is able to detect neoplastic cells in peripheral blood specimens, we suggest the necessity of a great caution in interpreting PCR results when the nested method has bee n used.