Relationship between methylation status of Rap1 GTPase activating protein and colon cancer / 肿瘤研究与临床

ABSTRACT

Objective To explore the methylation status of Rap1 GTPase activating protein (Rap1GAP) promoter in colon cancer, and to provide the oretical basis and research direction for the early diagnosis, targeted therapy, anti-multidrug resistance of colon cancer and so on. Methods The paraffin embedded specimens of 33 patients with colonic adenocarcinoma diagnosed by pathology were analyzed from Department of Pathology of Xinzhou City People′s Hospital from January 2010 to September 2014, including 19 males and 14 females, and aged 41-72 years old. The paraffin embedded specimens of 16 patients with colonic adenoma were enrolled, including 9 males and 7 females, and aged 34-58 years old. 13 normal tissues from the tumor distal margin (from the tumor > 15 cm) were selected. Quantitative methylation specific PCR (q-MSP) was applied to detect methylation level of Rap1GAP gene promoter. The methylation level differences of Rap1GAP gene promoter region among 3 groups or between different clinicopathologic factor subgroups were compared. Results The methylation rates [median (interquartile range)] of Rap1GAP promoter were 65.43 % (50.35 %), 21.37 % (8.39 %) and 17.43 % (15.71 %) in colonic adenocarcinoma group, colonic adenoma group and adjacent normal tissue group, respectively. The methylation rate of colonic adenocarcinoma group was significantly higher than that of colon adenoma group or that of adjacent normal tissue group (P60yearsold36.26%(62.62%)and26.23%(76.42 %);well-differentiated vs. moderately/poorly-differentiated 21.98 % (40.32 %) vs. 42.74 % (74.20 %); TNM Ⅰ-Ⅱ vsⅢ-Ⅳ 25.31 % (48.27 %) vs. 36.26 % (75.55 %); all P> 0.05]. Conclusion The methylation status of RAP1GAP promoter maybe associate with genesis and development of colon cancer, which might be used as a target for early diagnose of colon cancer.