Expression of epithelial-mesenchymal transition-related genes in prostate tumours

Aim. To detect expression of EMT-related genes in prostate tumor samples and analyze a possible correlation between the gene expression level and clinical characteristics of prostate cancer in different groups. Methods. Expression of 19 genes was analyzed in 37 frozen samples of prostate cancer tissues at different tumor stages and Gleason scores, 37 paired conventionally normal prostate tissues and 20 samples of prostate adenomas, using quantitative PCR. Results. We have found that nine genes were expressed differently in benign and malignant prostate tumors, namely AR (isoform 1), AR (isoform 2), PTEN , VIM, MMP9, KRT18, PCA3, HOTAIR and SCHLAP1 . When different tumor stages were compared, we could identify six differentially expressed genes: KRT18, MMP9, VIM, PCA3, HOTAIR and SCHLAP1 ; when samples of tumors with different Gleason score were compared, we found that eight genes were expressed differently: AR (isoform 1), CDH1, KRT18, MMP9, OCLN, PCA3, HOTAIR and SCHLAP1 . The datahad a high level of heterogeneity potentially due to various molecular subtypes of prostate cancer, i.e. a luminal subtype with a high expression of CDH1, OCLN, AR(1 isof), KRT18, NKX3-1 and PSA ; the stem-like subtype with the high expression of mesenchymal markers CDH2, FN1 and VIM and low expression of the epithelial markers. It is noteworthy that lncRNAs were specifically expressed in these two molecular subtypes. Conclusions. EMT-related genes were differentially expressed in benign and malignant prostate tumors. High heterogeneity of expression levels, especially in adenocarcinoma groups, might suggest the existence of at least two different molecular subtypes, luminal and stem-like. Further experiments are necessary for specification of the molecular subtypes of prostate adenocarcinoma.