The role of hypermethylation in the detection of gastric and colorectal cancer.

Gastrointestinal cancer is a prevalent disease with high morbidity and mortality. Tissue factor pathway inhibitor 2 () gene could protect the extracellular matrix of cancer cells from degradation and tumor invasion. The goal of our study was to estimate the diagnostic value of hypermethylation in gastric cancer (GC) and colorectal cancer (CRC). methylation was measured by quantitative methylation-specific polymerase chain reaction (qMSP) method in 114 GC and 80 CRC tissues and their paired non-tumor tissues. Our results showed that methylation was significantly higher in tumor tissues (GC: 29.940% vs. 12.785%, < 0.001; CRC: 26.930% vs. 5.420%, < 0.001). The methylation level of in colorectal tumor tissues was significantly higher than that in colorectal normal tissues (26.930% versus 0.002%, < 0.00001). In GC, hypermethylation yielded an area under the curve (AUC) of 0.762 (95% CI: 0.696-0.828) with a sensitivity of 68% and a specificity of 83%. In CRC, hypermethylation yielded an AUC of 0.759 (95% CI: 0.685-0.834) with a sensitivity of 61% and a specificity of 84%. Similarly, TCGA data also supported hypermethylation was a promising diagnostic marker for GC and CRC. Moreover, the dual-luciferase reporter assay showed fragment could upregulate gene expression (fold change = 5, = 0.005). Data mining further indicated that expression in CRC cell lines was significantly increased after 5'-AZA-deoxycytidine treatment (fold change > 1.37). In conclusion, hypermethylation might be a promising diagnostic biomarker for GC and CRC.