Identification of genes specifically deregulated in prostate
adenocarcinoma may lead to discovery of new oncogenes/tumour suppressors with clinical relevance for diagnosis, prognosis and/or
therapy. CXXC5 is a gene encoding a
retinoid-inducible nuclear factor, whose overexpression in breast tumours, metastatic
malignant melanomas and
papillary thyroid carcinoma has been recently reported. We previously found differential expression of CXXC5 transcripts in metastatic
prostate cancer cell lines of both rat and human origin. However, knowledge on the expression of this gene in benign or malignant human prostate tissue is lacking. The aim of this study was to determine the
mRNA and
protein expression pattern of CXXC5 in human benign prostate tissue, proliferative inflammatory
atrophy, high-grade prostatic intra-epithelial
neoplasia and
prostate cancer, using qPCR, chromogenic in situ hybridization and immunohistochemistry. Our results showed that
protein levels determined by immunohistochemistry were in agreement with transcript levels observed by chromogenic in situ hybridization. CXXC5
mRNA and
protein expressions were significantly higher in
prostate cancer, high-grade prostatic intra-epithelial
neoplasia, and proliferative inflammatory
atrophy, compared to benign prostate tissue. Significantly, within the same tissue specimens, CXXC5 staining was stronger in malignant acini than in matched adjacent, benign acini; immunostaining for this
protein was mainly localized to the nucleus of benign epithelial cells and both the nucleus and cytoplasm of malignant epithelial cells. Our findings suggest that CXXC5 may play a role in the process of prostate
carcinogenesis. Additional studies are required to determine the biological and clinical significance of CXXC5 in
prostate cancer development and/or progression.