Guo-qiang Qin,1,2,* Hui-chan He,2,* Zhao-dong Han,2,* Yu-xiang Liang,2 Sheng-bang Yang,2 Ya-qiang Huang,2 Liang Zhou,2 Hao Fu,2 Jie-xian Li,1,2 Fu-neng Jiang,2 Wei-de Zhong2–4 1Central Hospital of Panyu District, Guangzhou, People's Republic of China; 2Department of Urology, Guangdong Key Laboratory of Clinical Molecular Medicine and Diagnostics, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, People's Republic of China; 3Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou, People's Republic of China; 4Urology Key Laboratory of Guangdong Province, Guangzhou Medical University, Guangzhou, People's Republic of China *These authors contributed equally to this articleBackground: To clarify the involvement of HIVEP3 and SOX9 coexpression in prostate cancer (PCa).Methods: A small interfering RNA was used to knockdown SOX9 expression in a PCa cell line and to analyze the effects of SOX9 inhibition on the expression of HIVEP3 in vitro. Then, HIVEP3 and SOX9 expression patterns in the human PCa tissues were detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis and immunohistochemistry.Results: We found that the downregulation of SOX9 could inhibit the expression of HIVEP3 in the PCa cells in vitro. In addition, both HIVEP3 and SOX9 messenger RNA expression levels in the PCa tissues were significantly higher than those in the noncancerous prostate tissues (P=0.006 and P