Abstract. Type 2 diabetes mellitus (T2DM) is a leading cause of blindness, non-traumatic amputation and end-stage renal disease, as well as a major cardiovascular risk factor. To determine whether miR-125b and miR-34a serve an important role in the development of T2DM, the current study investigated the expression profile of two microRNAs (miR-34a and miR-125b) and their relative genes in peripheral blood mononuclear cells from 73 patients with T2DM and 52 healthy donors by reverse transcription-quantitative polymerase chain reaction In addition, the association between miR-34a, miR-125b and their relevant genes expression profile were analyzed with respect to the pathogenesis of T2DM. The present study demonstrated that the expression levels of miR-125b and miR-34a were elevated in peripheral blood mononuclear cell samples from patients with T2DM. Furthermore, miR-34a and miR-125b were positively correlated with low-density lipoprotein/high-density lipoprotein (HDL) and Foxp3 and negatively related to triglyceride/HDL. However, no correlation among miR-34a, miR-125b and the value of homeostasis model assessment of insulin resistance, homeostasis model assessment of β-cell function and the genes of B lymphocyte-induced maturation protein-1, interferon regulatory factor-4, P53 and retinoid-related orphan receptor γt were observed. These results indicate that the alteration of miR-34a and miR-125b exists in patients with T2DM, which may be involved in the pathogenesis of T2DM, and could be a potential novel biomarker of T2DM. IntroductionType 2 diabetes mellitus (T2DM), formerly termed non-insulin-dependent diabetes mellitus or adult-onset diabetes, is a multifactor disease that involves complex interactions between genes (1-3), abnormalities of the immune system (4-6), environmental factors (7-10) and health-impacting behavior (11,12), and represents a serious public health problem in numerous developed countries (13). Current investigations have revealed a definite global increase in the incidence and prevalence of diabetes. In 2013, 382 million people worldwide were estimated to be diabetic by the International Diabetes Federation, which is expected to rise to 592 million cases in the year 2035 (14). As a result of the increasing rate of diabetes and its widespread societal and economic consequences, prevention of diabetes among people at high risk is an important public health issue in clinic practice. However, the extent to which multiple defects in the regulation of lipids, insulin secretion and action, and the immune system contribute to the pathogenesis of T2DM has yet to be elucidated.MicroRNAs (miRNAs) are a class of small, single-stranded non-coding RNAs (~22 nucleotides) that are transcribed from the DNA of a gene, and modulate the expression of a network of mRNAs through binding to the 3'-untranslated region (3'-UTR), 5'-UTR or to the open reading frame of target mRNAs (15). Notably, each miRNA is able to target multiple mRNAs. Growing evidence indicates that miRNAs are involved in T2DM (16). However,...