SPINK7 and esophageal squamous cell carcinoma: Along with other researchers, we have long carried on the etiological and epidemiological investigation of numerous aspects of the high Kazakh ESCC incidence rate, which may include traditional habits and customs, such as eating hot meals, hard foods, yogurt knots, and tea; smoking; lack of folic acid; natural geographical environment [31]; genetic factors, such as PLCE1, hRFT1, and ECRG2 [14, 32, 33]; and microbial factors, such as HPV [34].