transcription-quantitative polymerase chain reaction and western blot assays were performed to examine the effect of rs3746444 on the expression of miR-499a and cd200. The results demonstrated a significant difference in the smoking history of patients carrying malignant pulmonary nodules

The present study evaluated the association between single nucleotide polymorphism (SNP) rs3746444 and the risk of non-small cell lung carcinoma (NScLc) in a chinese population. computational analyses and luciferase assays were performed to investigate the regulatory relationship between miR-499a and cd200. In addition, reverse transcription-quantitative polymerase chain reaction and western blot assays were performed to examine the effect of rs3746444 on the expression of miR-499a and cd200. The results demonstrated a significant difference in the smoking history of patients carrying malignant pulmonary nodules and those carrying benign pulmonary nodules. Furthermore, cd200 was demonstrated to be a direct target of miR-499a, and a miR-499a binding site was located in the 3'UTR of cd200. Notably, the levels of miR-499a in malignant pulmonary nodules were higher compared with benign pulmonary nodules, while the levels of cd200 were higher in benign pulmonary nodules compared with malignant pulmonary nodules. In addition, the subjects carrying the AA genotype of SNP rs3746444 exhibited upregulated miR-499a expression and reduced cd200 expression, compared with the subjects carrying AG and GG genotypes. These findings indicate that the SNP rs3746444 in miR-499a could affect the prognosis of NScLc patients by regulating the expression of cd200. Introduction In total, >80% of lung carcinomas are non-small cell lung carcinoma (NScLc), which includes large cell carcinoma, squamous cell carcinoma, adenocarcinoma, and unclassifiable NScLc. The prognosis of patients with lung cancer is significantly affected by the cell type (for example, small cell vs. NScLc), clinical staging, and the overall condition of the patients. Unfortunately, NScLc is frequently diagnosed at a late stage, thus limiting the number of available treatment options. Since pulmonary nodules may be observed in specific NScLc cases, the difference between malignant and benign pulmonary nodules has been used as a diagnostic criterion of NScLc (1). As a family member of immunoglobulin (Ig) proteins, cluster of differentiation 200 (cd200; also known as OX-2) carries two extracellular immunoglobulin domains and one small 19 amino acid intracellular domain with no known signaling motifs (2). cd200 is expressed in a wide range of human cancer types, including malignant B carcinoma, myeloid leukemia, ovarian cancer and human melanoma (3-6). A previous study has demonstrated that intravenous injection of cd200+ B16 cells into CD200R‐deficient mice induced significant tumor growth in multiple organs, including kidney, lung, liver and the peritoneal cavity (7). As small non-coding RNAs containing 19-25 nucleotides, microRNAs (miRNAs) are able to mediate the expression of numerous protein-coding genes in animals and plants. In addition, miRNAs have important roles in a number of cellular processes, including stem cell renewal, cell metabolism, proliferation, apoptosis and differentiation (8). due to the important functions of miRNAs, their abnormal expression has been implicated in many human diseases, including obesity, cardiovascular diseases, cancer, psoriasis, schizophrenia, chronic hepatitis and diabetes (9-14). For example, a previous study (15) demonstrated that miR-499a-5p serves as a tumor suppressor to regulate the expression of vav guanine nucleotide exchange factor 3 (VAV3), and that low expression levels of miR-499a-5p are correlated with a poor prognosis in NScLc. Experimental data has additionally demonstrated that overexpression of miR-499a-5p inhibits the proliferation and Single nucleotide polymorphism rs3746444 in miR‐499a affects susceptibility to non‐small cell lung carcinoma by regulating the expression of CD200 NAN GE1*, cHUNXIA MAO2*, QINGBO YANG1, BIN HAN1, YONGJIE WANG1, LINHAO XU1, XIUZHI YANG3, WENJIE JIAO1 and cHUAN LI1 departments of 1Thoracic Surgery, 2Hematology and 3Operation Room, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China Received February 6, 2018; Accepted March 4, 2019 dOI: 10.3892/ijmm.2019. 4124 Correspondence to: Professor Wenjie Jiao or Professor chuan Li, department of Thoracic Surgery, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, Shandong 266003, P.R. china E-mail: drlung@yeah.net E-mail: lcxlh1218@sina.com *contributed equally