Polymorphisms of Mir-34b/c, Mir-146a and Mir-196a-2 and Predisposition to Chronic Lymphocytic Leukemia and Monoclonal B-Cell Lymphocytosis

Abstract 4585

Since microRNAs control expression of protein-coding oncogenes and tumor suppressor genes, functional microRNAs single nucleotide polymorphisms (SNPs) may modulate the risk of tumorigenesis including susceptibility to chronic lymphocytic leukemia (CLL). In this case-control study we investigated whether pri-miR-34b/c rs4938723 (T-to-C), miR-196a2 rs11614913 (C-to-T) and miR-146a rs2910164 (G-to-C) SNPs influence predisposition to CLL or monoclonal B-cell lymphocytosis (MBL). miR-34 family members are direct transcriptional targets of tumor suppressor p53, and miR-34b/miR-34c have been recently proposed as regulators of TCL1 (T-cell leukaemia/lymphoma 1) expression in CLL. A rs4938723 SNP in the promoter region of pri-miR-34b/c might affect transcription factor GATA binding and pri-miR-34b/c expression. Alterations in miR-196a2 and miR-196a2 may represent common cancer predisposition pathways as miR-196a2 rs11614913 and miR-146a rs2910164 have been recently associated with altered risk of different solid tumors including breast, lung, prostate and liver cancers. Additionally, we verified the impact of these microRNA SNPs on prognostic factors and clinical course of CLL. Genotyping was performed using PCR-based assays in a total of 561 Caucasians including 195 patients with CLL, 166 patients with MBL and 200 healthy control individuals. The assessed minor allele frequencies (MAFs) of the investigated SNPs were as follows: for rs4938723 SNP C allele frequency was 0.37 in CLL, 0.36 in MBL and 0.30 in controls, for rs11614913 SNP T allele frequency reached 0.43 in CLL, 0.42 in MBL and 0.39 in controls, and for rs2910164 SNP C allele frequency was 0.29 in CLL, 0.30 in MBL and 0.26 in controls. Logistic regression analysis did not detect significant associations of CLL or MBL with studied genotypes or alleles (p>0.05). Moreover, none of the tested genetic variants was found to influence CLL patients’ progression-free survival (PFS) or overall survival (OS) with median follow-up time from diagnosis of 3.0 (0–13.9) years. In conclusion, our data suggest that investigated SNPs in pri-miR-34b/c, miR-146a and miR-196a-2 genes are not likely to play a major role in the susceptibility to CLL and MBL or in clinical outcome of CLL.