Potential diagnostic implications of miR-144 overexpression in human oesophageal cancer

Background & objectives: Insidious symptomatology, late clinical presentation and poor prognosis of oesophageal cancer (EC) highlight the pressing need for novel non-invasive biomarkers for early tumour diagnosis and better prognosis. The present study was carried out to evaluate the clinical significance of circulating and tissue miR-144 expression in oesophageal cancer. Methods: Clinical significance of miR-144 expression was evaluated in preneoplastic (12) and neoplastic (35) oesophageal cancer tissues as well as matched distant non-malignant tissues using real-time PCR (qPCR). Circulating levels of miR-144 were also analyzed in serum samples of EC patients as well as normal individuals to determine the diagnostic potential of miR-144. Further, targets of miR-144 were predicted using bioinformatic tools and their gene ontology (GO) terms were assigned. Results: Real-time PCR analysis revealed significant upregulation of miR-144 in 29 of 35 (83%) EC tissues as compared to matched distant non-malignant tissues (P=0.010). All the dysplastic tissues showed upregulation of miR-144 as compared to their matched distant non-malignant tissues. Relative levels of circulating miR-144 in serum significantly distinguished EC patients from normal controls (P= 0.015; AUC = 0.731) with high sensitivity of 94.7 per cent. Bioinformatically predicted target, PUR-aplha (PURA) was found to be significantly (P= 0.018) downregulated in 81 per cent (26/32) EC patients and its expression was found to be significantly and negatively correlated with miR-144 expression at mRNA level. Interpretation & conclusions: Our findings showed significant upregulation of miR-144 in serum samples of EC patients indicating its potential as minimally invasive marker. Further studies need to be done to understand the role of miR-144 in the pathogenesis of EC.