The comparison of miR-155 with computed tomography and computed tomography plus serum amyloid A protein in staging rectal cancer.

Recently identified class of microRNAs (miRNAs) provided a new insight in cancer research. As a member of miRNAs family, miR-155 expression demonstrated the correlation with tumor stage. Thus, its expression level can be potentially used for staging rectal tumors. The aim of this study was to systematically evaluate the potential abilities of miR-155 in preoperatively N staging.Expression of miR-155 was detected and quantitated in rectal cancer tissues and in adjacent nonmalignant tissues from 40 patients by TaqMan MicroRNA assays. Preoperative enhanced computed tomography (CT) scan, serum amyloid A protein (SAA), carcinoembryonic antigen (CEA), and postoperative pathologic biopsy were performed.A significant overexpression of miR-155 was observed in rectal carcinoma tissues (0.137 ± 0.095 versus 0.093 ± 0.091, P = 0.043). High expression of miR-155 in N1-2 (0.09 ± 0.038 versus 0.183 ± 0.111, P = 0.001) and III and IV stages (0.091 ± 0.039 versus 0.178 ± 0.111, P = 0.002) presented its potential correlation with N and tumor-node-metastasis combined stages. Receiver operating characteristics curve analysis showed that miR-155 could discriminate N0 from N1-2 with 85.0% sensitivity and 85.0% specificity at the cutoff value of 0.125. miR-155 and CT had nearly equal performances in sensitivity (0.850 versus 0.700, P = 0.450) and specificity (0.850 versus 0.550, P = 0.077) in predicting N1-2 stage. Compared with CT + SAA, miR-155 had similar sensitivity (0.850 versus 0.950, P = 0.617) but higher specificity (0.750 versus 0.200, P = 0.015) for lymph node assessment.Increase in the expression of miR-155 might represent a potential valuable marker for rectal carcinoma N and combined tumor-node-metastasis staging.