Phenotypic differences of stroma cells in benign and malignant human prostate tissues

OBJECTIVE: To analyze the stroma changes of benign and malignant human prostate tissues. METHODS: For the identification of stroma cells phenotype in human prostate cancer and benign prostate hyperplasia tissues, Masson method and immunohistochemical analysis of α-smooth muscle actin (α-SMA), desmin, and vimentin were performed. The relative volume of intratumor stroma (0%, Grade 0; 1% - 33%, Grade 1; 34% - 66%, Grade 2; 67% - 100%, Grade 3) were quantified and analyzed in local and advanced prostate cancer tissues. RESULTS: Stroma myofibroblasts in prostate cancer were stained green by Masson staining and showed a co-expression of α-SMA and vimentin without an expression of desmin. It was significantly different from smooth muscle cells in benign prostate hyperplasia stained red and co-expressing a-SMA and desmin. Statistical analysis showed that high stroma volume (Grade 2/3) in advanced prostate cancer were significantly higher than that in an early stage of prostate cancer (83% vs 55%, P < 0.05). CONCLUSION: Significant phenotypic differences of stroma cells existed in benign and malignant human prostate tissues. A high expression of myofibroblasts in advanced prostate cancer may play an important role in cancer progression. And its clinical significance should raise a high alert.