Breast carcinomas are found to express different CKs, such as the luminal subtype expressing luminal epithelial CKs (CK8/CK18/CK19) or the basal subtype expressing basal myoepithelial high molecular weight (HMW) CKs (CK5/CK6/ CK7/CK14) [4, 45, 46]. Here, KRT18 is linked to breast carcinoma.