To study correlation between sperm-associated antigen 9 (SPAG9) and epithelial-mesenchymal transition (EMT), extracelluar matrix (ECM)-associated protein in prostate cancer.

The immunohistochermical analysis was used to detect the expression of SPAG9, E-cadherin, Vimentin and matrix metalloproteinase-2 (MMP-2) in 60 specimens of prostatic carcinoma (PCa) and 30 specimens of benign prostate hyperplasia (BPH). Statistical analyses were used to evaluate the relationship between SPAG9 and E-cadherin, Vimentin, MMP-2.

The immunohistochermical analysis showed the average integral absorbance (IA) of each protein in metastatic PCa, nonmetastatic PCa and BPH as follows: for SPAG9 (466.34±13.52, 284.98±25.69 and 106.01±13.58, the differences were all statistically significant, P=0.000); for Vimentin (285.79±15.85, 184.20±21.31 and 79.56±7.96, the differences were all statistically significant, P=0.000); for MMP-2 (269.97±15.74, 175.82±21.81 and 87.86±17.61, the differences were all statistically significant, P=0.000). The IA values of these proteins were reduced successively in the three groups; however, the IA values of E-cadherin (148.62±28.31, 286.73±18.73 and 417.73±12.90, the differences were all statistically significant, P=0.000) were increased successively in the three groups. Pairwise comparisons of each protein’s IA within the three groups revealed the statistically significant differences. There was a positive correlation between SPAG9 and Vimentin (r_s=0.443, P=0.014), MMP-2 (r_s=0.443, P=0.001) while negative correlation was existed between SPAG9 and E-cadherin (r_s=-0.431, P=0.017).

SPAG9 may promote the occurrence and development of PCa by regulating EMT, ECM-associated proteins.

Sperm-associated antigen 9; Epithelial-mesenchymal transition; Extracelluar matrix; Prostatic carcinoma