Cellular retinoic acid-binding protein 2 is down-regulated in prostate cancer.

Prostate cancer is among the most frequent tumours in industrialized nations and many questions remain open concerning the molecular events underlying its development and progression. In the present study we have combined cDNA array hybridization to laser-assisted microdissection (LAM) in order to investigate differences in gene expression between epithelial and stromal cells of prostate cancer and normal peripheral prostate tissue. Results have been verified for selected candidate genes by quantitative real-time RT-PCR. Using this approach and immunohistochemistry we could demonstrate a down-regulation of cellular retinoic acid binding protein 2 (CRABP2) mRNA and protein in carcinoma cells compared to normal glandular cells. CRABP2 is a main regulator of anti-carcinogenic activities of retinoic acid and may become a novel diagnostic marker and experimental therapeutic tool for prostate cancer. In addition, results of cDNA array hybridization suggest an up-regulation of 34 further genes and a down-regulation of 6 genes in cancer tissues compared to normal peripheral prostate tissues. Several of these genes have already been reported to be associated with carcinogenesis in organs such as the prostate.