Expressions Of NDRG1 And Nm23 In Colorectal Neoplasms And Correlations With Tumor Metastasis

Objective: To study the functions of NDRG1 and nm23 genes in colorectal carcinogenesis and to investigate their correlations with tumor metastasis.Methods: NDRG1 and nm23 were detected at their protein levels by immunohistochemical (IHC) staining and image analysis (IA) technique, and NDRG1 messenger RNA (mRNA) was detected by in situ hybridization (ISH) in normal colorectal mucosae, colorectal adenomas, colorectal carcinomas with no regional lymph nodes metastasis, colorectal carcinomas with regional lymph nodes metastasis and their corresponding regional lymph nodes metastatic sites.Results: NDRG1 proteins were gradually increased in colorectal carcinogenesis. What's more, there was significantly difference between the expressions of NDRG1 in colorectal carcinomas with no regional lymph nodes metastasis and those with regional lymph nodes metastasis, and the correlation was positive (P=0.002, rs=0.329), whereas there was no obvious difference between the expressions of NDRG1 in the primarysites of colorectal carcinomas and those in the corresponding regional lymph nodes metastatic sites, nor was there apparent difference in sex, age, histological type and tumor invasion. The expressions of NDRG1 mRNA were generally concordant with the expressions of NDRG1 protein. As far as another gene, nm23, was concerned, no significant differences of its protein expressions were found in colorectal carcinogenesis. nevertheless, most of the carcinomas with regional lymph nodes metastasis showed reduced nm23 expression, as compared to the carcinomas with no regional lymph nodes metastasis, and the correlation was negative (P=0.004, rs=-0.456). But there was no obvious difference between the expressions of nm23 in the primary sites of colorectal carcinomas and those in the corresponding regional lymph nodes metstatic sites, nor was there apparent difference in sex, age, histological type and tumor invasion. There was no obvious correlation between the expressions of NDRG1 and the expressions of nm23.Conclusions: NDRG1 gene may play an important role in colorectal carcinogenesis. In addition, NDRG1 can be a putative tumor metastasis enhancer gene and is promisingly being regarded as one of the molecular biological markers that can forecast early metastasis of colorectal carcinomas. Nm23 can inhibit colorectal carcinoma metastasis and can be a tumor metastasis suppressor gene and is promisingly being regarded as another molecular biological indicator that can forecast early metastasis of colorectal carcinomas. Additionally, the facts that there were no significant differences of the expressions of nm23 proteins in colorectal carcinogenesis indicated that nm23 gene can not distinguishbetween normal colorectal tissues and colorectal neoplasms, nor can it distinguish between benign colorectal neoplasms and malignant colorectal neoplasms. NDRGl and nm23 in the regional lymph nodes metastatic sites might still preserve their expressive characteristics in the primary sites of colorectal carcinomas to some extend. There was no obvious correlation between the expressions of NDRG1 and the products of nm23, which indicated that they may play different roles respectively in the different processes of colorectal carcinomas metastasis.