J Cancer 2018; 9(16):2865-2875. doi:10.7150/jca.25270 This issue
1. The First Affiliated Hospital of Jiaxing University, Jiaxing, China
2. Tumor Affiliated Hospital of Xinjiang Medical University, Urumqi, China
3. The Medical School of Jiaxing University, Jiaxing, China
4. Department of Health Toxicology, College of Public Health, Xinjiang Medical University, Urumqi, China
Objective: To investigate the relationship between the hypermethylation of folic acid metabolism-related genes and the incidence and prognosis of esophageal cancer among ethnic Kazakhs in Xinjiang (China).
Methods: According to the standard of esophageal cancer diagnosis, exclusion and epidemiological investigation of the experimental and control groups. Ion capture immunoassays were used to measure serum folic acid levels, while methylation-specific polymerase chain reaction was used to detect gene promoter methylation levels. Log-rank tests and Cox regression models were used to identify prognostic factors in the patient population.
Results: Serum folic acid levels in the experimental (cancer) group were significantly lower than in the control (non-cancer) group (Z = -9.13, P < 0.001). Furthermore, the methylation rates of MTHFR, CBS, MGMT, P16, FHIT, and RASSF1A in the experimental group were significantly higher than in the control group. Multivariate analysis identified depth of tumor invasion, regional lymph node metastasis, tumor-node-metastasis stage, and CBS and RASSF1A gene methylation status as independent prognostic factors; female gender and high serum folic acid levels were favorable prognostic factors.
Conclusions: Low serum folic acid level is a risk factor for esophageal cancer among ethic Kazakhs. Moreover, methylation of MTHFR, CBS, MGMT, P16, FHIT, and RASSF1A is closely related to esophageal cancer tumorigenesis.
Keywords: DNA methylation, esophageal cancer, folic acid metabolism, Kazakh people, prognosis.