Clinical Significance Of MiR-499-5p Expression In Colorectal Cancer And Colorectal Adenomas

BackgroundColorectal cancer (colorectal cancer, CRC) is a common digestive tract malignant tumor, which of incidence and mortality rates is rising in recent years. MicroRNA (miRNA, miR) is a kind of endogenous non-coding single-stranded RNA molecules. Recently research has shown that different microRNA expression in colorectal cancer tissue level is different. The expressions of microRNA are closely linked to occurrence, development and prognosis of colon cancer. Recent studies reported that some microRNA, such as miR-143, miR-145 and miR-21, play an important role in pathogenesis of colon cancer. But, the relevant research of miR-499-5p in colon polyps and colorectal cancer has not been reported.ObjectiveStudy was inspected the expressions of miR-499-5p in normal colon tissue, colorectal adenomas tissue and the colorectal cancer tissue. Their correlation with clinic pathologic features of colorectal cancer was analyzed. This research aimed to explore the role of miR-499-5p in development of colorectal adenomas and colorectal cancer, and to provide a theoretical basis for pathogenesis and early discovery of patients with colorectal cancer.MethodsWe collected paraffin embedding colon cancer, colonic adenoma and normal colon tissue specimens each 40 cases, which were diagnosed from January 2013 to January 2014 years. We classified colon cancer and colorectal adenomas tissue as experimental group, normal colon tissue specimens as control group. All clinicopathological data were obtained from clinical and pathologic records. The expression levels of miR-499-5p in colorectal cancer, colorectal polyps and normal tissues were detected by using stem-loop real-time reverse transcription-polymerase chain reaction (qRT-PCR), With U6 as an internal reference. The datas were analyzed by SPSS 17.0 program. The measurement data were expressed as standard deviation (x±SD) and tested by independent samples t-test or One-Way ANOVA. The enumeration datas were tested by ^-test. Inspection level is α=0.05. P<0.05 is the level of significant difference.Results1. The results of qRT-PCR showed that expressions of miR-499-5p in the colorectal cancer, colorectal adenomas and normal colon groups were12.15±5.83,3.63±0.93 and 1.00±0.04. There were significant difference in the expression of miR-499-5p among three groups (F=80.143, P<0.05). Multiple compared each other in these 3 groups, expression in colorectal adenomas group were higher than that in normal colon groups. There was significant difference between the two groups (P<0.05). Expressions in colorectal cancer group were higher than that in normal colon group and colorectal adenomas group. There was significant difference between the two groups (P<0.05).2. The expression of miR-499-5p in colorectal adenomas tissue was not associated with the age, gender and pathological calssification. The expression of miR-499-5p in colorectal adenomas tissue was associated with the diameter of colorectal adenomas. Expressions in the small adenomas (diameter<1cm), middle adenomas (1≤diameter<2cm) and big adenomas (diameter≥2cm) were 3.27±2.29,3.44±2.28 and 3.29±2.05. There were significant difference in the three groups (F=5.696, P<0.05). Comparing the pairwise comparisons, between middle adenomas tissues (1≤diameter<2cm) and big adenomas tissues (diameter>2cm) and the small adenomas tissues (diameter<1cm) the difference was statistically significant (P<0.05).3. The expression of miR-499-5p in colorectal cancer tissues was not associated with the age, gender, tumor size and distant metastasis. Expression in colorectal cancer tissue was associated with the degree of differentiation, which in well-differentiated groups, moderately differentiated groups, poorly differentiated groups were 9.22±2.10,11.24±4.06 and 21.33±3.89. There were significant difference among three groups (F=26.300,P<0.05). Multiple compared each other in these 3 groups, expression in moderately differentiated groups were higher than that in well-differentiated groups. There was significant difference between the two groups (P<0.05). Expressions in poorly differentiated groups were higher than that in the other two groups. There was significant difference between the two groups (P<0.05). The expression of miR-499-5p in colorectal cancer tissue was associated with TNM stage, which in stage Ⅰ, stage Ⅱ, stage Ⅲ and stage Ⅳ were 8.36±1.30,11.21±4.78,15.80±5.78 and 16.83±6.92. There were significant difference among the four groups (F=3.954, P<0.05). The expression of miR-499-5p in colorectal cancer tissue was associated with the depths of invasion, which in T1+T2, T3+T4 groups were 9.10±1.73 and 14.46±6.05. There were significant difference between the two groups (t=4.439, P<0.05). The expression of miR-499-5p in colorectal cancer tissue was associated with the lymph node metastasis. Expressions of miR-499-5p in colorectal cancer with positive and negative lymph nodes were 15.87±6.12 and 11.11±4.06. There were significant difference between the two groups (t=-2.783, P<0.05).Conclusions1. Expression levels of miR-499-5p are gradually increased in normal colon mucosa, colonic adenoma, colon carcinoma tissues, and that show dynamic changes in the process of carcinogenesis of colon carcinoma.2. miR-499-5p may be involved in the early neoplasia of colon cells. There is correlation between expression levels of miR-499-5p with the diameters of the adenoma. But, the effect of miR-499-5p is smaller in the process of adenoma of malignant differentiation.3. miR-499-5p may be oncogene, which participates in the development of colon cancer. There is a close correlation with tumor metastasis and invasion. miR-499-5p is expected to become an evaluation index of tumor biological behavior and prognosis.