Prognostic significance of miR 499 expression and Helicobacter pylori infection in malignant lesions of gallbladder cancer: a clinicopathological study

Gallbladder cancer (GBC) is an infrequent type of malignant neoplasm worldwide. There are a number of risk factors that increase a person's likelihood of developing GBC. Gallbladder inflammatory (GID) diseases including cholelithiasis increase the risk of GBC, and this is further complicated by the fact that Helicobacter pylori (H. pylori) infection is extremely common in gastrointestinal tract in India. Since both miR 499 and H. pylori infection are found to be linked with tumor progression and metastasis, therefore there is a possibility that H. pylori might be involved in inflammation via dysregulation of miR 499. The study was designed to investigate the association of miR 499 expressions with H. pylori infection and their correlation with clinicopathological parameters of GBC. The hundred three tissue samples used in this study are categorized into GID (n = 55) and GBC (n = 48). The expression of miR-499 was examined by using the Livak method for relative gene expression analysis. The presence/absence of H. pylori infection was examined by RT-PCR (Liferiver Helicobacter pylori RT-PCR Kit). Helicobacter pylori infection and GBC/GID cases were not significantly correlated. Decreased expression of miR 499 was observed in GBC (1.6 fold) as compared to GID patients (P < 0.0001). Low miR 499 expression was found to significantly correlate with tumor differentiation (P = 0.017), advanced staging (P = 0.004) and liver metastasis (P = 0.036). Multivariate regression analysis showed significant association of overall survival with low miR 499 expressions. miR 499 may be considered as a useful prognostic biomarker in GBC progression.