Abstract:

OBJECTIVE: The aim of this study was to identify the expressions of E2F5 and MYC gene located in chromosomal region 8q21–24 in prostate cancer (PCa)，adjacent benign prostate tissues and PCa cell lines，to analyze their expression levels and to explore theirs significances in PCa. METHODS：DNA qPCR analysis was carried out to evaluate the copy number changes of E2F5 and MYC genes in PCa tissues and PCa cell lines. Western blot and immunohistochemical staining were used to assess expressions of E2F5 and MYC in PCa and BPH tissues，and analyzed together with clinical pathological parameters. RESULTS：DNA qPCR revealed a significant copy number gain of E2F5 and MYC in PCa tissues but not in PCa cell lines (P<0.05 or P<0.01). In addition，Western blot analysis and immunohistochemical staining both found the significantly higher expression of E2F5 and MYC proteins in PCa tissues than those in adjacent benign specimens (all P<0.01). Moreover，the overexpression of E2F5 protein was significantly associated with a high Gleason score (P<0.01)，an advanced clinical stage (P=0.01)，a positive metastasis (P<0.01) and biochemical recurrence (P<0.01). The overexpression of MYC was more frequently found in PCa tissues with positive metastasis (P=0.02) and biochemical recurrence (P=0.02). Interestingly，there was a close correlation in the expression level of MYC in PCa tissues with that of E2F5 (rs=0.5，P<0.01). CONCLUSION：Overexpressions of E2F5 and MYC may play an important role in the development and progression of PCa. E2F5 may be a novel potential candidate marker for malignant PCa.

Key words: prostate cancer, E2F5, MYC, qPCR, imunohistochemistry, Western blot