Análise da expressão e do número de cópias gênicas de microrna da região 8q24.21 no câncer gástrico ; Analysis of 8q24 microRNA cluster expression and copy number variation in gastric cancer.

Objective: To analyze the expression of miR1204, miR1205, miR1206, miR1207 and miR1208 in neoplastic and nonneoplastic gastric tissue from patients with and without GC, determine the reference genes for this analysis, the number of gene copies of these miRNAs, and to associate these variables with the clinical and pathological parameters of GC patients. Methods: The expression of miR1204, miR1205, miR1206, miR12075p, miR12073p, and miR1208 target miRNA was evaluated by RTqPCR in 65 paired neoplastic (T) and adjacent nonneoplastic (A) samples from patients with GC, and 20 nonneoplastic gastric tissue samples from cancerfree individuals submitted to endoscopy (C), and determined by the ΔCt method. The number of copies of the miR1204, miR1205, miR1207, and miR1208 genes was determined by qPCR in 69 T samples using the Copy Caller program. Results: The C group of samples did not differ in relation to gender and age of CG patients (p> 0.05). Only miR1205 presented different expression between A and C groups, with higher expression in A group (p = 0.02). Expression of miR1204 and miR1206 was not observed in the analyzed gastric tissue samples. A strong positive correlation was observed between miR12075p and miR1208 expression (p <0.01, ρ = 0.71), and a very weak positive correlation between miR1205 and miR12073p expression (p = 0.04, ρ = 0.21). No association was observed between miR1205, miR12075p, miR12073p, and miR1208 expression and the number of copies of their respective genes (p> 0.05). Increased miR1207 gene copy number was associated with tumors located in noncardiac region of the stomach (p = 0.01), and the loss of copies of miR1208 gene was associated with H. pylori infection (p = 0.01). Conclusion: No significant differences were found between miR1205, miR12075p, miR12073p, and miR1208 expression in T vs A and T vs C samples. However, miR1205 showed an increased expression in A samples compared to C samples. The results suggest that miR1205 participates in the beginning of GC development. In ...