The expression of miR-21 in prostate cancer measured by in situ hybridization and its relevance as a diagnostic biomarker

Abstract

Background: Micro RNAs (miRNA) are a novel class of molecular regulators that have gained considerable attention in cancer research. Multiple studies in recent time have reported altered miRNA regulation in most cancers by deregulating of oncogenes and tumour suppressor genes. Additionally, certain tumours are represented by specific miRNA expression files. Prostate cancer is a markedly heterogeneous disease with considerable variation in clinical course ranging from asymptomatic disease to rapidly progressing fatal malignancy. The repertoire of prognostic markers is currently limited to preoperative serum-PSA, clinical or pathological stage, histological grade, and surgical margin. Experimental design: In this study the expression of a well-known miRNA, miR-21, was examined whether it could have prognostic significance in prostate cancer. The expression was measured by chromogen in situ hybridization performed on tissue microarrays from prostate cancer, and the expression was compared to clinical and pathological information to determine its potential as a biomarker. Results and conclusion: Univariate analyses indicate that miR-21 is an independent biomarker for biochemical failure and clinical failure but not cancer-specific death. To fully determine the value of miR-21 potential, it must be further analysed with multivariate analysis and be validated in an additional cohort to exclude local cofounders.