SOX2 expression in the developing, adult, as well as diseased prostate

BACKGROUND: SOX2 is a member of SOX (SRY-related HMG box) family of transcription factors. METHODS: in this study, we examined the expression of SOX2 in murine and human prostatic specimens by immunohistochemistry. RESULTS: we found that SOX2 was expressed in murine prostates during budding morphogenesis and in neuroendocrine (NE) prostate cancer (PCa) murine models. Expression of SOX2 was also examined in human prostatic tissue. We found that SOX2 was expressed in 26 of 30 benign prostate hyperplasia (BPH) specimens. In these BPH samples, expression of SOX2 was limited to basal epithelial cells. In contrast, 24 of 25 primary PCa specimens were negative for SOX2. The only positive primary PCa was the prostatic NE tumor, which also showed co-expression of synaptophysin. Additionally, the expression of SOX2 was detected in all prostatic NE tumor xenograft lines. Furthermore, we have examined the expression of SOX2 on a set of tissue microarrays consisting of metastatic PCa tissues. Expression of SOX2 was detected in at least one metastatic site in 15 of 24 patients with metastatic castration-resistant PCa; and the expression of SOX2 was correlated with synaptophysin. CONCLUSIONS: SOX2 was expressed in developing prostates, basal cells of BPH, as well as prostatic NE tumors.