POU5F1P1, a Putative Cancer Susceptibility Gene, Is Overexpressed in Prostatic Carcinoma

BACKGROUND. Association between genetic variants located on human chromosome 8q24.21 with an increased risk for prosta tic carcinoma has been well established. POU5F1P1, a processed pseudogene homologous to the pluripotency factor OCT4, is the only sequence with coding capacity in this region. The objective of this study was to investigate the POU5F1P1 expression in prostatic carcinoma and carcinoma surrounding prostatic tissue. METHODS. RT-PCR and real-time PCR was used to measure the expression of POU5F1P1 relative to the expression of HPRT1 in cell lines, prostatic carcinoma and carcinoma surrounding prostatic tissue. The structure of the POU5F1P1 mRNA and the promoter sequence were elucidated by 5'-RACE experiments. The POU5F1P1 protein was shown with immunohistochemistry on prostate tissue. RESULTS. POU5F1P1 was found to be the only member of the POU5F1 family to be expressed in prostate with over-expression in prostatic carcinoma compared to surrounding prosta tic tissue probably because of an increased density of expressing cells. The POU5F1P1 expression is driven by a variety of promoter structures, scattered over a genomic region of 860 kB. CONCLUSIONS. The over-expression of POU5F1P1 in prosta tic carcinoma in addition to its genomic location and the putative function of its gene product render POU5F1P1 a good candidate to harbour functional genetic variants which modulate prostatic cancer susceptibility. Prostate 70: 666-674, 2010. (C) 2009 Wiley-Liss, Inc.