IMMUNOHISTOCHEMICAL EVALUATION OF PROLIFERATING CELL NUCLEAR ANTIGEN,PROSTATE-SPECIFIC ANTIGEN AND ALPHA-1-ANTICHYMOTRYPSIN IN HUMAN PROSTATE-CANCER

Objective To determine the relationship between growth fractions defin ed by proliferating cell nuclear antigen (PCNA), prostate-specific ant igen (PSA) and al-antichymotrypsin (ACT) staining in prostate cancer. Materials and methods A total of 96 lesions, including 71 from prostat e cancers and 25 from benign prostatic hyperplasia (BPH) were evaluate d in microscopic sections of the prostatic tissues from 34 patients wi th prostate cancer. Immunohistochemical staining was performed with an avidin-biotin system using monoclonal anti-PCNA antibodies, polyclona l anti-PSA and anti-ACT antibodies. Results There was a significant di fference in the mean PCNA labelling index between tissue from prostate cancer (4.2+/-7.1) and BPH (0.5+/-1.1) (P=0.002). The mean labelling index of PCNA tended to increase with increasing Gleason score. The pr oportion of cells positive for PSA was significantly higher in tissue from BPH than from prostate cancer (P=0.005). While the proportion of cells immunostaining for ACT was significantly higher in tissue from B PH compared to that from prostate cancer (P=0.02), there was no signif icant difference in the proportion of ACT-positive cells among prostat e cancers of differing Gleason score. The mean labelling index of PCNA decreased significantly with the increase in the proportion of PSA-po sitive cells (P=0.013). There was a significant relationship between t he proportion of ACT- and PSA-positive cells (P=0.001). Conclusion The se results indicate a reciprocal relationship between cell growth and tumour differentiation in prostate cancer. Although the significance o f ACT deserves further study, there was evidence for the complexing of PSA with ACT from the immunohistochemical studies.