E1AF expression is associated with extra‐prostatic growth and matrix metalloproteinase‐7 expression in prostate cancer

E1AF is associated with malignant aggressiveness via regulation of matrix metalloproteinases (MMPs), which play pivotal roles in invasion through the degradation of extracellular matrix of tissues surrounding tumors. However, the clinical significance of E1AF and MMPs in patients with prostate cancer is not fully understood. We reviewed 50 tissue samples from patients with T2‐3N0M0 prostate cancer who had undergone radical operation. Expression levels of E1AF, MMP‐1, ‐3, ‐7, ‐9 and ‐14 were determined semiquantitatively by immunohistochemistry. The mean ± SD percentage of E1AF‐stained cancer cells was 8.56 ± 5.22, and it was significantly higher (p < 0.001) than the E1AF‐immunostaining index of normal cells (1.17 ± 0.61). E1AF immunostaining index in pT3 (12.74 ± 4.80) was significantly higher (p < 0.001) than that in pT2 (5.78 ± 3.31). Although E1AF expression correlated with that of MMP‐7 and MMP‐9 (r = 0.47, p < 0.001 and r = 0.41, p = 0.004, respectively), multivariate analysis showed that E1AF correlated with only MMP‐7 expression (OR = 5.81, 95% CI = 1.27–26.59, p = 0.023). Our results demonstrated that increased expression of E1AF is involved in tumor aggression of prostate cancer. This finding may be influenced by regulation of MMP‐7. We speculate that E1AF is a possible target in treatment and prevention of tumor growth in prostate cancer.