モノクローナル抗体Ki-67を使用した前立腺吸引組織スメアにおける増殖細胞に関する研究

Abstract

前立腺肥大症30例, 肉芽腫性前立腺炎(結核)1例, 前立腺癌22例, 前立腺部移行上皮癌1例および膀胱移行上皮癌の前立腺浸潤1例より採取した検体を材料とした.経直腸的吸引細胞診法は各症例に対し1回行い, 全視野における総細胞数が1, 000に満たないものは原則として除外した.吸引スメアに対してモノクローナル抗体Ki-67を使用した免疫組織化学染色を行った.1)前立腺癌の増殖能は前立腺良性疾患に比して明らかに高かった.2)低分化型腺癌は, 高および中分化型腺癌に比してKi-67 labeling indexが若干高値を示した.3)移行上皮癌は腺癌に比してKi-67 labeling indexが高値を示した.4)経直腸的前立腺吸引細胞診法に本染色法を応用することは, 前立腺癌早期診断の一助となる

Immunohistochemical staining using monoclonal antibody Ki-67 was performed in 30 patients with benign prostatic hypertrophy (BPH), one with prostatic tuberculosis (TB), 22 with prostatic adenocarcinoma, one with prostatic transitional cell carcinoma and one with prostatic invasion from a bladder cancer. Specimens were aspirated from the prostate transrectally and a cytological smear were made. This antibody is specific for a proliferation-associated nuclear antigen. Alkaline phosphatase anti-alkaline phosphatase stained immunopositive nuclei red making positive or negative specimens easy to recognize. In BPH and TB smears, no immunopositive cell was reactive with Ki-67. In prostatic malignancy were found many immunopositive cells ranging from 2.5 to 10.2% (mean 5.9%) in prostatic adenocarcinoma (n = 22), and from 11.9 to 24.3% (mean 18.1%) in prostatic transitional cell carcinoma. Transitional cell carcinoma may have a much greater growth fraction than adenocarcinoma in prostatic tissue. Poorly differentiated adenocarcinoma showed a higher growth fraction (from 4.2 to 10.2%, mean 6.9%) than well differentiated (from 3.1 to 8.9%, mean 5.8%) and moderately differentiated adenocarcinoma (from 2.5 to 10.1%, mean 5.6%), but this difference was not significant. There was no correlation with age, clinical stage, bone metastasis or Bocking's cytological grade. In conclusion, immunohistochemical staining using Ki-67 on aspirated prostatic smear is visualizes the growth fraction of prostatic disease well and is useful to diagnose prostate cancer.