Detection of prostate specific antigen messenger RNA from pelvic lymph node in prostate cancer

We have adapted a sensitive method to detect pelvic lymph node metastasis using reverse transcriptase-polymerase chain reaction (RT-PCR) with primers specific for prostate-specific antigen (PSA) gene. Fine needle aspiration biopsy (FNAB) of pelvic lymph nodes was performed in 25 patients with prostate cancer. Each aspirated sample (0.05–0.1 mL) was divided into two parts: one for RNA extraction and RT-PCR to detect the fragment of PSA mRNA, and the other to smear on a slide glass for conventional cytology. RT-PCR detection of PSA gene was positive in 12 cases of FNAB samples, which included not only all 6 cytologically positive and 2 cytologically class III cases but also 4 of 17 cytologically negative cases. RT-PCR of FNAB samples of all 20 cases of bladder cancer were negative for the detection of PSA gene. RT-PCR for detection of PSA gene in FNAB samples may become a new diagnostic technique for detection of early lymph node metastasis in prostate cancer and an additional tool for cytologic diagnosis of prostate cancer.