IL4 and esophageal squamous cell carcinoma: In another study, Omar et al. assessed polymorphisms of the IL-1, IL-4, IL-6, and IL-10 gene cluster in a population of upper gastrointestinal cancers, including gastric cardia and non-cardia adenocarcinomas, esophageal squamous cell carcinoma and adenocarcinoma and in frequency-matched controls.