Aberrant methylation of and in peripheral blood leukocytes and their association with gastric cancer risk.

Aberrant DNA methylation, especially tumor suppressor gene hypermethylation, is a well-recognized biomarker of initial tumorogenesis stages. and are putative tumor suppressor genes and can be down-regulated by hypermethylation in various cancers tissues. However, in peripheral blood leukocytes, the association between these two genes methylation status, as well as the effects of gene-environment interactions, and gastric cancer (GC) risk remain unclear. A hospital-based case-control study including 375 cases and 394 controls was conducted. Peripheral blood leukocytes DNA methylation status were detected by methylation-sensitive high-resolution melting (MS-HRM) assay. Logistic regression was adopted to analyze the relationship of and methylation with GC susceptibility. Positive methylation (Pm) and total positive methylation (Tpm) of were significantly increased the risk of GC (OR = 2.204, 95% CI: 1.168-4.159, = 0.015; OR = 1.583, 95% CI: 1.031-2.430, = 0.036, respectively). Compared with controls, cases exhibited higher Pm frequencies with OR of 2.530 (95% CI: 1.289-4.969, = 0.007). Nonetheless, no statistically significant association between Tpm and GC risk was observed. Additionally, interactions between Tpm and increased consumption of freshwater fish (≥1 times/week) displayed an antagonistic effect on GC (OR = 0.328, 95% CI: 0.142-0.762, = 0.009), and high salt intake interacted with Tpm also showed statistically significant (OR = 0.490, 95% CI: 0.242-0.995, = 0.048). aberrant methylation in peripheral blood leukocytes and gene-environment interactions were associated with the risk of GC, while was controversial and needed to be more investigated.