Differential expression of MSX2 in nodular hyperplasia, high-grade prostatic intraepithelial neoplasia and prostate adenocarcinoma

One of the common features in advanced prostate cancer is bone metastasis. In this study, we investigated the clinical relevance of a bone factor, MSX2, in predicting the metastatic ability of prostate adenocarcinoma. Evaluation of MSX2 expression was performed using prostate cell lines as well as patient specimens. A sharp decrease in MSX2 was found in primary prostate cancer cells, 22Rv1, when compared with the non-malignant counterparts, followed by a gradual increase in more aggressive prostate cancer cell lines. Interestingly, the MSX2 protein was upregulated and predominantly expressed in the nucleus in aggressive prostate cancer cell line, C4-2b, compared with the less aggressive 22Rv1. Consistent with the in vitro results, MSX2 nuclear expression was significantly higher in nodular hyperplasia when compared with high-grade prostatic intraepithelial neoplasia (PIN), while MSX2 nuclear expression in prostate adenocarcinoma was higher than that in high-grade PIN. Importantly, MSX2 expression was increased significantly in tumors with metastasis compared with those without metastasis. Finally, MSX2 nuclear scores were significantly increased in patients with preoperative serum PSA20 ng/mL. No correlation between MSX2 nuclear score and Gleason score was found. Taken together, MSX2 may serve as a potential biomarker in predicting primary prostate tumors with higher metastatic capability.