RT-PCR法による前立腺癌患者末梢血中のPSA mRNAの検出に関する研究

Abstract

Nested RT-PCR法に用いて, 前立腺癌患者の末梢血中より前立腺腫瘍マーカーであるPSAのmRNAを検出し, 臨床診断, 血清PSA値, 手術標本などと対比検討し, 本法が臨床的にいかなる意義があるかを検討した. 1)未治療前立腺癌では臨床病期がすすむにしたがいRT-PCRの陽性率が上昇し, 本法が病期診断を行う際の有用な情報を提供しうる可能性が示唆された. 2)Neoadjuvant療法(CAB療法)後の前立腺全摘除術施行症例において, 切除断端陽性例でRT-PCR陽性となる傾向が見られ, 本法が手術適応を決定する際の補助的手段として有用であると考えられた. 4)CAB療法施行中の転移を有する症例では再燃の有無とRT-PCRの結果に相関を認め, 前立腺癌の再燃の診断に応用できる可能性が示唆された

A sensitive technique using reverse transcription and polymerase chain reaction (RT-PCR) has been used to detect circulating tumor cells in the peripheral blood of men with prostate cancer. We evaluated the clinical utility of this method for staging and monitoring for prostate cancer. Peripheral blood from 39 patients with prostate cancer and 7 non-prostate cancer controls was analyzed for prostate specific antigen (PSA) messenger RNA (mRNA) using RT-PCR. In 8 among 22 patients (36.4%) with clinically localized prostate cancer (T2 or T3), PSA mRNA was detected by RT-PCR (RT-PCR positive). Five out of 8 patients (62.5%) with regional lymph node and/or bone metastases were RT-PCR positive. The number of patients with RT-PCR positive was more frequent in a higher clinical stage. In 22 patients with clinically localized prostate cancer, 2 of the 9 patients who underwent radical prostatectomy had positive surgical margins and both patients were RT-PCR positive. Six of the 7 patients with negative surgical margin were RT-PCR negative. In the 9 cases that had been treated by combined antiandrogen blockade for metastatic prostate cancer, 4 patients whose serum PSA level were less than 4 ng/ml were all RT-PCR negative. More over 4 of 5 patients with more than 4 ng/ml of serum PSA level were RT-PCR positive. All control samples were RT-PCR negative. This study suggested that this technique using RT-PCR may provide useful information in treating patients with prostate cancer, especially for candidates for radical prostatectomy. The value of this modality as a prognostic factor awaits for further follow-up.