Purpose: EPCA, a nuclear matrix protein, has been identified as a novel prostate cancer marker through protein profiling analyses comparing prostate cancer and its normal counterpart. A recent study of prostate biopsy specimens revealed that EPCA stained positive in the cancer negative biopsy cores of individuals with cancer at later biopsy. We clarified the relationship between EPCA expression and clinicopathological parameters, including grade and stage. Morphological characteristics of EPCA positive cells in noncancerous tissues were also analyzed.
Materials and methods: Prostate tissue specimens were obtained from 50 patients with localized prostate cancer and 10 with invasive bladder cancer. EPCA expression was analyzed with a polyclonal antibody. Anti-P504S/anti-p63/anti-34betaE12 monoclonal antibodies were used for adjunct diagnosis for prostatic intraepithelial neoplasia. A monoclonal antibody, CD45RO, was used to confirm inflammatory infiltrates surrounding focal atrophic glands.
Results: EPCA staining was positive in the prostate samples of 94% of patients with prostate cancer but it was completely negative in samples from patients with bladder cancer. There was no correlation of EPCA staining intensity with Gleason grade or pT stage. In noncancerous tissues adjacent to major cancer foci EPCA was positive in 86% of prostate cancers. Most EPCA positive glands adjacent to cancer consisted of prostatic intraepithelial neoplasia and proliferative inflammatory atrophy.
Conclusions: EPCA seems to reflect nuclear matrix alterations that occur in the earlier stage of prostate carcinogenesis. Individuals in whom the prostate is influenced by this field effect may be detected with this new biomarker.