OBJECTIVE: To investigate the DNA methylation status of the promoter region within the coding gene hsa-miR-124a in human gastric cancer tissue, and examine its association with the expression of Rb and CDK6 protein and clinicopathological factors. METHODS: Methylation-specific PCR (MS-PCR) was used to detect the DNA methylation status of hsa-miR-124a in gastric cancer tissues and adjacent normal tissues from 30 patients. The expression of Rb and CDK6 protein within these tissues was examined using immunohistochemistry. RESULTS: The overall methylation rate of gastric cancer tissues was 73.3%, which was significantly higher than that in the adjacent tissues(10.0%, P<0.05). The overall positive rates of Rb and CDK6 protein in gastric cancer tissues were 86.7% and 80.0%, respectively. DNA methylation of hsa-miR-124a was positively correlated with the expression of Rb and CDK6 proteins. Significant associations were found between hypermethylation of hsa-miR-124a and tumor size, differentiation, lymphatic metastasis, and invasion depth(P<0.01). CONCLUSIONS: Hypermethylation of hsa-miR-124a is present in gastric cancer, and is associated with increased expression of CDK6 and Rb protein. These may be related to the proliferation and development of malignancy in the stomach.
OBJECTIVE: To investigate the DNA methylation status of the promoter region within the coding gene hsa-miR-124a in humangastric cancer tissue, and examine its association with the expression of Rb and CDK6 protein and clinicopathological factors. METHODS: Methylation-specific PCR (MS-PCR) was used to detect the DNA methylation status of hsa-miR-124a in gastric cancer tissues and adjacent normal tissues from 30 patients. The expression of Rb and CDK6 protein within these tissues was examined using immunohistochemistry. RESULTS: The overall methylation rate of gastric cancer tissues was 73.3%, which was significantly higher than that in the adjacent tissues(10.0%, P<0.05). The overall positive rates of Rb and CDK6 protein in gastric cancer tissues were 86.7% and 80.0%, respectively. DNA methylation of hsa-miR-124a was positively correlated with the expression of Rb and CDK6 proteins. Significant associations were found between hypermethylation of hsa-miR-124a and tumor size, differentiation, lymphatic metastasis, and invasion depth(P<0.01). CONCLUSIONS: Hypermethylation of hsa-miR-124a is present in gastric cancer, and is associated with increased expression of CDK6 and Rb protein. These may be related to the proliferation and development of malignancy in the stomach.