Combination of microRNA-21 expression with the serum marker CA19-9 increases the accuracy of diagnosis of pancreatic adenocarcinoma
Pancreatic adenocarcinoma (PA) is one of the most aggressive malignant tumors of the digestive tract, with a five-year survival rate of 5%. Early detection offers better possibilities of cure; however, in early stages it does not present symptoms, making the management of these patients difficult. The most commonly used biomarker for diagnosis of PA is serum CA19-9, which has a sensitivity between 70 and 80%, although, with less than 50% specificity, due to its expression in various other types of cancer. The reduced rate of apoptosis plays a crucial role in carcinogenesis, in which the cytotoxic attack and the effectiveness of pharmacological treatment are reduced. Therefore, it would be useful to associate the biomarker CA19-9 with other molecular tools to increase the accuracy of the diagnosis, such as microRNAs (miRNAs) that target apoptotic genes. The association between the expression profile of anti-apoptotic microRNAs (miRNA-15a and miRNA-16), pro-apoptotic microRNAs (miRNA-21, miRNA-221 and miRNA-222) and serum CA19-9 was evaluated for the diagnosis of pancreatic ductal adenocarcinoma. Twenty pancreatic tumor tissue samples, after microdissection from patients diagnosed with pancreatic adenocarcinoma, were studied. As a control, seven samples of normal pancreas from cadaveric donors or patients undergoing pancreatic resection due to trauma were used. Serum CA19-9 was measured and the expression analysis of miRNA-21, miRNA-221, miRNA-222, miRNA-15a and miRNA-16 was measured using real-time quantitative PCR. The usefulness of pro-apoptotic and anti-apototic microRNAs alone or in association with CA19-9 in the diagnosis of PA was evaluated. The expression of miRNA-21 was significantly associated with PA, when compared with control samples. There was no significant difference in the expression of the other miRNAs. We conclude that association of CA19-9 and microRNA-21expression would increase sensitivity and accuracy in the diagnosis of PA.