miR-422a is an independent prognostic factor and functions as a potential tumor suppressor in colorectal cancer.

AIM: To determine the expression of miR-422a in colorectal cancer (CRC) tissues and to further explore the prognostic value and function of miR-422a in CRC carcinogenesis. METHODS: miR-422a expression was analyzed in 102 CRC tissues and paired normal mucosa adjacent to carcinoma by quantitative real-time PCR. The relationship of miR-422a expression with clinicopathological parameters was also analyzed. Kaplan-Meier analysis and Cox multivariate analysis were performed to estimate the potential role of miR-422a. Cell proliferation, migration, and invasion were used for in vitro functional analysis of miR-422a. RESULTS: The levels of miR-422a were dramatically reduced in CRC tissues compared with normal mucosa (P < 0.05), and significantly correlated with local invasion (P = 0.004) and lymph node metastasis (P < 0.001). Kaplan-Meier survival and Cox regression multivariate analyses revealed that miR-422a expression (HR = 0.568, P = 0.015) and clinical TNM stage (HR = 2.942, P = 0.003) were independent prognostic factors for overall survival in CRC patients. Furthermore, in vitro experiments showed that overexpression of miR-422a inhibited the proliferation, migration, and invasion of SW480 and HT-29 cells. CONCLUSION: Down-regulation of miR-422a may serve as an independent prognosis factor in CRC. MiR-422a functions as a tumor suppressor and regulates progression of CRC.

Overexpression of miR-223 correlates with tumor metastasis and poor prognosis in patients with colorectal cancer.

The purpose of the study was to investigate microRNA-223 (miR-223) expression in colorectal cancer (CRC) and its relationship with tumorigenesis and disease prognosis. Quantitative real-time PCR was used to measure levels of miR-223 in tumor samples and adjacent non-cancerous tissues from 62 patients undergoing radical resection for the treatment of CRC. The associations between miR-223 expression and patient age, sex, as well as clinicopathologic parameters, such as tumor size, differentiation, location, invasion depth, metastasis, tumor-node-metastasis (TNM) stage, and overall patient survival, were analyzed by Mann-Whitney U and Kruskal-Wallis tests. Kaplan-Meier method and Cox proportional hazards regression analyses were performed to estimate the prognostic factors for patient survival prediction. The expression of miR-223 was significantly upregulated in CRC tissues compared with adjacent non-cancerous tissues (P < 0.05). This overexpression was associated with TNM stage and lymph node and distant metastases, (P < 0.05). Moreover, Kaplan-Meier analysis demonstrated that patients with high miR-223 expression had a poorer overall survival (OS) than those with low miR-223 expression (P = 0.002). Univariate analysis revealed a statistically significant correlation between OS and miR-223 level, histology grade, metastasis and TNM stage (P < 0.001). Furthermore, miR-223 levels and histology grade were independently associated with OS (HR 0.204, 95 % CI 0.101-0.415, P < 0.05 and HR 2.252, 95 % CI 1.429-3.546, P < 0.05, respectively). The overexpression of miR-223 may play an important role in the progression of CRC and can be used as an independent factor to determine CRC prognosis.

Decreased expression of miR-133a correlates with poor prognosis in colorectal cancer patients.

AIM: To investigate microRNA-133a (miR-133a) expression in colorectal cancer (CRC) and its relationship with tumorigenesis and disease prognosis. METHODS: Quantitative real-time polymerase chain reaction was used to measure levels of miR-133a in tumor samples and adjacent non-cancerous tissues from 169 patients undergoing radical resection for CRC. The associations between miR-133a expression and patient age, sex, as well as clinicopathologic parameters, such as tumor size, differentiation, location, invasion depth, metastasis, tumor-node-metastasis (TNM) stage and overall patient survival, were analyzed by Mann-Whitney U and Kruskal-Wallis tests. The Kaplan-Meier method and Cox proportional hazards regression analyses were performed to estimate the prognostic factors for patient survival prediction. RESULTS: The expression of miR-133a was significantly downregulated in CRC tissues compared with adjacent non-cancerous tissues (P < 0.05). This reduction was associated with the depth of the local invasion, poor differentiation, lymph node metastasis and advanced disease (P < 0.05). Moreover, Kaplan-Meier analysis demonstrated that patients with low miR-133a expression had poorer overall survival (OS) than those with high miR-133a expression (P < 0.001). Univariate analysis revealed statistically significant correlations between OS and miR-133a level, tumor local invasion, lymph node metastasis and TNM stage (P < 0.001). Furthermore, miR-133a levels and TNM stage were independently associated with OS (HR = 0.590, 95%CI: 0.350-0.995, P < 0.05; and HR = 6.111, 95%CI: 1.029-36.278, P < 0.05, respectively). CONCLUSION: The downregulation of miR-133a may play an important role in the progression of CRC and can be used as an independent factor to determine CRC prognosis.