The Relationship Between Keratin 18 and Epithelial-Derived Tumors: As a Diagnostic Marker, Prognostic Marker, and Its Role in Tumorigenesis

Keratin 18 (K18) is a structural protein with significant roles in epithelial-derived tumors, acting as a diagnostic and prognostic marker due to its altered expression in cancers like lung, breast, liver, and gastrointestinal cancers. K18 influences tumorigenesis, invasion, metastasis, and drug resistance through its interactions with various proteins and signaling pathways, such as MAPK, PI3K/Akt, and mTOR. In breast cancer, K18 is involved in apoptosis resistance and epithelial-mesenchymal transition (EMT), while in hepatocellular carcinoma, it affects cytoskeletal stability and metabolism. Despite its potential, further research is needed to fully understand K18's molecular mechanisms and interactions in cancer progression.