In consideration of a colon-rectal cancer diagnosis of his father at the age of 45 years, we carried out a Search Tool for the Retrieval of Interacting Genes/Proteins and Pymol-based Protein Data Bank study and found that interleukin-4 may be the key factor supporting the occurrence of hyperplastic polyps in collagenous gastritis. The gene discussed is IL4; the disease is rectal cancer.