Jian-Chun Cai1, Di Liu, Hai-ping Zhang, San Zhong, Nig-shao Xia. 1. Department of Oncological Surgery, Xiamen Cancer Center, Xiamen First Hospital, Affiliated to Fujian Medical University, China. jianchunfh2@sina.com
Abstract
OBJECTIVE: To study the promoter hypermethylation of several tumor suppressor genes in gastric carcinoma (GC) tissue and adjacent normal gastric foveolar epithelium (GFE). METHODS: Methylation specific PCR (MSP) was used to examine the promoter methylation of tumor suppressor genes E-cadherin, hMLH1, APC and MGMT in paraffin-embedded gastric cancer tissue and adjacent normal foveolar epithelium in 106 cases. RESULTS: The positive rate of genes promoter methylation was 44.3% (47/106 cases) and 72.6% (77/106 cases) at one or more genes tested in the normal GFE and GC tissue, respectively. There was a significant difference in the positive rates of gene promoter methylation between normal GFE and GC tissue (P = 0.0001). There was a significant association with Laurén classification, degree of differentiation and pTNM staging in GC (P < 0.05), but no significant association with Ming's classification (P > 0.05). CONCLUSION: Tumor suppressor genes promoter methylation is frequently present in GC and adjacent normal gastric foveolar epithelium, especially in Laurén diffuse type GC, poorly differentiated GC, mucus-secreting (signet ring) cell GC and pTNM stage III and IV GC. Our findings indicate that the gene promoter methylation is a common and early event in GC carcinogensis.
OBJECTIVE: To study the promoter hypermethylation of several tumor suppressor genes in gastric carcinoma (GC) tissue and adjacent normal gastric foveolar epithelium (GFE). METHODS: Methylation specific PCR (MSP) was used to examine the promoter methylation of tumor suppressor genes E-cadherin, hMLH1, APC and MGMT in paraffin-embedded gastric cancer tissue and adjacent normal foveolar epithelium in 106 cases. RESULTS: The positive rate of genes promoter methylation was 44.3% (47/106 cases) and 72.6% (77/106 cases) at one or more genes tested in the normal GFE and GC tissue, respectively. There was a significant difference in the positive rates of gene promoter methylation between normal GFE and GC tissue (P = 0.0001). There was a significant association with Laurén classification, degree of differentiation and pTNM staging in GC (P < 0.05), but no significant association with Ming's classification (P > 0.05). CONCLUSION:Tumor suppressor genes promoter methylation is frequently present in GC and adjacent normal gastric foveolar epithelium, especially in Laurén diffuse type GC, poorly differentiated GC, mucus-secreting (signet ring) cell GC and pTNM stage III and IV GC. Our findings indicate that the gene promoter methylation is a common and early event in GC carcinogensis.