Cancer/testis antigen SPATA19 is frequently expressed in benign prostatic hyperplasia and prostate cancer

Spermatogenesis‐associated 19 (SPATA19) is a cancer/testis antigen overexpressed in various cancers. However, its protein expression profile in malignant or non‐malignant tissues remains unknown. Thus, in this study, we investigated SPATA19 protein expression patterns in a panel of non‐malignant human samples and primary prostate cancer (PCa) with or without benign prostatic hyperplasia (BPH) tissues. SPATA19 was absent in all non‐malignant tissues investigated (n=14) except testis and prostate tissues. In terms of malignancies, all PCa cases were positive for SPATA19 exhibiting frequency between 20 and 100% (median 85%) with 63 (52.5%) and 57 (47.5%) cases demonstrating weak/moderate and strong intensities, respectively. Thirty‐nine PCa cases (32.5%) contained BPH, and all BPH glands were SPATA19 positive (frequency between 20 and 100%; median 90%) with 13 (33.3%) demonstrating strong SPATA19 expression. Higher SPATA19 expression (higher frequency, intensity, or H‐score) was not associated with overall survival or disease‐specific survival (DFS) in all PCa cases. However, biochemical recurrence (BR) was associated with worse DFS (p = 0.005) in this cohort of 120 patients, and cases with strong SPATA19 intensity were associated with BR (p = 0.020). In conclusion, we showed that SPATA19 protein was frequently expressed in both BPH and PCa glands, and this warrants future investigations on its pathogenic roles in the disease.