| Objective:Colon cancer is a common malignancy in the digestive system.The morbidity and mortality rates of colon cancer are ranked the third and fifth of cancer in Chinese population.It has tendency to increase recently.The occurrence of colon cancer is a process of long-term evolution.The activation and inactivation of many oncogenes are involved.The curative treatment and prognosis of colon cancer are closely related to the clinical stage.The 5-year survival rate of early colon cancer is above 90%,while this rate of advanced colon cancer with distant metastasis is only 12%.Early diagnosis depends on diagnostic techniques that have high sensitivity,high specificity.Although fecal occult blood and DNA examination is simple,non-invasive,and easy to be accepted by the patients,their sensitivity and specificity are low.Colonoscopy is currently the best method for diagnosing colon cancer.However,colonoscopy is costly,needs gastrointestinal preparation before examination,discomfort and may have complications such as perforation and bleeding.Some patients refuse this procedure and the compliance is therefore,poor.Exploring the potential modalities to diagnose colon cancer is critically important.A large number of researches have shown that there are differences in the gene expression profiles(mRNA)of colon cancer tissues and adjacent mucosa.These aberrantly expressed genes can be used as markers for the diagnosis of colon cancer.Nancy et al.reported that not only the gene expressions in colon cancer tissues are aberrant,but also in other parts of intestinal mucosa including the rectum.they demonstrated that abnormal mRNA expressions in rectal mucosa epithelium can be used as a molecular marker for the diagnosis of colon cancer.However,the nature of mRNA is unstable,easily degradable,and requires high preservation conditions for clinical specimens,which limits its clinical application.MicroRNAs(miRNAs)are non-coding small RNAs that regulate gene expression at the post-transcriptional level.They are stable in nature and are not easily degraded.miRNAs regulate tumor cell proliferation,invasion,and metastasis.Our group searched Pubmed database for the colon cancer microRNA expression lineage and found that the abnormally high expression of miRNA-182-5p is related to the colon cancer.We therefore compared the expression of miRNA-182-5p in paraffin-embedded cancer tissues and fresh tissues of cancer and paracancer from patients with colon cancer to verify the the correlation between miRNA-182-5p expression and the tumor size,invasiveness,stage and differentiation.We found that the expression of miRNA-182-5p was significantly higher not only in cancer and paracancer tissues,but also in non-cancer tissues in rectum of patients with colon cancer than that in healthy subjects,which indicated that miRNA-182-5p may be potentially valuable in colon cancer screening.Method:1.A total of 30 paraffin-embedded specimens were collected from patients with colon cancer diagnosed in Department of Pathology,Affiliated Hospital of Chengde Medical College from December 2015 to January 2017;A total of 42 fresh colonic mucosa specimens from patients with colon cancer and 31 cases of rectal mucosa(5 cm from the anus)in healthy volunteers were collected by colonoscopy from January 2017 to December 2017.2.Using RT-qPCR method to detect the expression of miRNA-182-5p in paraffin-embedded colon cancer tissue and colon colon biopsy fresh colon cancer tissues,paracancer mucosa,rectal mucosa and healthy control rectal mucosa.3.Using SPSS 23.0 software for data processing,statistical analysis of real-time fluorescence quantitative PCR detection results,the measurement data of normal distribution(x ± s)that the comparison between groups using t test,P <0.05 The difference was statistically significant.Result:1.In the paraffin-embedded specimens,the expression levels of miRNA-182-5p in colon cancer tissues were significantly higher than that in adjacent tissues(38.62±5.71 vs 24.29±6.55,P<0.05).2.The expressions of miR-182-5p in paraffin-embedded colon cancer tissues were not significantly different from that in fresh colon cancer tissues(38.62±5.71 vs 36.34±6.15,P>0.05).3.The expressions of miRNA-182-5p in fresh rectal mucosa(24.03±5.56)and adjacent tissues(25.95±5.23)were significantly lower than that in colon cancer tissue(36.34±6.15).The miRNA-182-5p contents in healthy control group(8.13±2.75)were significantly lower than those of the other three groups(P<0.05).Conclusion:miRNA-182-5p is not only abnormally elevated in colon cancer tissues,but also significantly increased in rectal mucosa of patients with colon cancer compared with that of healthy subjects.miRNA-182-5p is a potential bio-marker in the diagnosis of colon cancer. |
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