Genome-wide association studies have identified thousands of SNPs associated with predisposition to various diseases, including prostate cancer. However, the mechanistic roles of these SNPs remain poorly defined, particularly for noncoding polymorphisms. Here we find that the prostate cancer risk-associated SNP rs339331 at 6q22 lies within a functional HOXB13-binding site. The risk-associated T allele at rs339331 increases binding of HOXB13 to a transcriptional enhancer, conferring allele-specific upregulation of the rs339331-associated gene RFX6. Suppression of RFX6 diminishes prostate cancer cell proliferation, migration and invasion. Clinical data indicate that RFX6 upregulation in human prostate cancers correlates with tumor progression, metastasis and risk of biochemical relapse. Finally, we observe a significant association between the risk-associated T allele at rs339331 and increased RFX6 mRNA levels in human prostate tumors. Together, our results suggest that rs339331 affects prostate cancer risk by altering RFX6 expression through a functional interaction with the prostate cancer susceptibility gene HOXB13.

The angiogenesis inhibitor histidine-rich glycoprotein (HRG) constitutes one of several examples of molecules regulating both angiogenesis and hemostasis. The antiangiogenic properties of HRG are mediated via its proteolytically released histidine-and proline-rich (His/Pro-rich) domain.

BackgroundThe CIP2A protein is a recently characterized oncoprotein which inhibits protein phosphatase 2A activity. Expression of CIP2A has been detected in several carcinomas, but its expression and significance in prostate cancer has not been examined so far.MethodsExpression of the CIP2A protein was studied using immunohistochemistry in prostate cancer (n = 59) and in benign prostatic hyperplasia (n = 20) specimens. The CIP2A staining scores were compared with several clinicopathological parameters.ResultsExpression of CIP2A was increased in prostate cancer epithelium as compared with the benign hyperplastic epithelium (p < 0.001). The expression of CIP2A was associated with high Gleason scores (p < 0.001) and among patients treated with radical prostatectomy, CIP2A expression was associated with pre-treatment risk stratification (p = 0.011) and pathological T-class (p = 0.031). No statistically significant association was detected between CIP2A expression and prostate specific antigen concentrations.ConclusionsExpression of the CIP2A protein is increased in prostate cancer specimens and its expression is associated with poorly differentiated and high-risk tumors.