Tissue inhibitor of metalloproteinases 3 promoter methylation and mRNA expression in cardia carcinoma and its relationship with prognosis

Abstract

Objective To explore the relationship of the methylation levels of tissue inhibitor of metalloproteinases 3(TIMP-3) gene promoter CpG islands with the invasiveness and prognosis in cardia carcinoma. Methods The tumors tissues were collected from 65 patients with cardia carcinoma. The methylation levels of the promoter of TIMP-3 gene were detected by methylation-specific PCR(MSP), the mRNA expression levels of TIMP-3 gene were detected by RT-PCR. The relationship of TIMP-3 gene ectopic methylation with invasiveness and prognosis of the cardia carcinoma patients was analyzed. Results The positive expression rates of TIMP-3 mRNA in gastric cancer and normal gastric tissues were 53.8 % (35/65) and 96.9 % (63/65), respectively. The difference was not statistically significant(Fisher exact test, P=0.912). The positive rate of TIMP-3 mRNA was negatively correlated with the depth of tumor invasion and lymph node metastasis [mucosa and muscular vs. serosa and mucosa outside of the serosa and muscula: 83.3 % (10/12) vs. 45.3 % (24/53); with lymph node metastasis vs. without lymph node metastasis: 73.9 % (17/23) vs. 40.5 % (17/42)] (both P<0.05). There was a negative correlation between TIMP-3 gene promoter methylation and TIMP-3 mRNA expression (r=-0.276, P=0.026). The size of tumor and TIMP-3 gene promoter methylation were both the independent influencial factors of prognosis in cardia carcinoma(both P<0.05). Conclusion The methylation of promoter region in CpG islands plays an important role in the invasion and metastasis of cardia carcinoma, and it can be used as an independent predictor of biological behavior and prognosis. Key words: Stomach neoplasms; Tissue inhibitor of metalloproteinase 3; Methylation; RNA, messenger; Prognosis