MUC5AC and neoplasm: Comparison of malignant epithelium to no malignant ones put into evidence overexpression of tumour specific genes like REG4, TFF3, CLDN4 and CLDN7. Genes involved in gastric mucus and enzyme secretion like GKN1, PGC, MUC5AC and LIPF were more expressed in non-tumorous epithelium [11].