STX18 and prostate cancer: To test whether selected autoantigens are differentially expressed in different progression stages of prostate cancer, we undertook a comparative immunohistochemistry analysis of SPAST, SPOP and STX18 employing an independent TMA comprising 111 tissue specimens from histological normal prostate (BE), benign prostate hyperplasia (BPH), prostate primary carcinoma (CA) as well as from clinically diagnosed castration resistant prostate cancer (CRPC).