Clinical Evaluation Of MiR-93-5p Expression In Rectal Cancer Tissues

OBJECTIVE: Rectal cancer,one of the most common cancers worldwide,is one of the leading causes of cancer-related deaths in China.Due to early symptom of colorectal cancer usually hidden,defecate habits are much similar to some benign diseases,early diagnosis is difficult,the majority of patients diagnosed with is in the late.Growing evidence suggests that microRNAs(mi RNAs)play a key role in the initiation and progression of rectal cancer.There is specific expression of miRNAs in many cancers and as a role of anti-oncogene or oncogene.The aim of this study was to analyze miRNA expression profiles to clarify their associations with clinicopathologic data and to evaluate the potential of miRNAs as diagnostic and prognostic markers of rectal cancer.METHODS: Tissues were collected from patients who received primary surgery from Dec 2015 to June 2016 were acquired from Anhui Provincial Hospital,China.Patients were considered eligible if they had pathologic confirmation of rectal cancer by professional pathologists and had no prior chemoradiotherapy.Samples including rectal cancer tissues and the matched adjacent normal tissues(on the side opposite to the pathological changes)from each patient were collected from formalin-fixed,paraffin-embedded tissues immediately after surgery.Then every patient's pathological stage was verified by experienced doctors.Five pairs of samples were detected by microRNA microarray first.The top five differentially expressed miRNAs were validated by real-time qRT-PCR.One or two validated miRNAs were selected for further evaluation in an independent cohort of 71 samples from patients with rectal cancer.RESULTS: Compared to the matched adjacent normal tissues,rectal cancer tissues had 138 over-expressed and 116 down-regulated miRNAs among a total of 3100 miRNAs detected by the microarray.In consideration of fold-change and value of ForeGround-BackGround,5 miRNAs were selected to verify the result in qRT-PCR.Particularly,over-expression of miR-93-5p and down-regulation of miR-27a-3p became prominent.Regression analysis identified that miR-93-5p over-expression,but not miR-27a-3p down-regulation,correlated with tumor volume(P=0.004),number of lymph nodes metastasis(rs=0.534,P=0.005)and the expression level of carcinoembryonic antigen(CEA)(P=0.001),the most widely used tumor marker for rectal or colorectal cancer.CONCLUSIONS: There is a differential miRNA expression pattern between rectal cancer tissues and matched adjacent normal tissues.MiR-93-5p is highly up-regulated in rectal cancer and may serve as a diagnostic and prognostic marker of this cancer.