Cytokeratin 20

Cytokeratin 20 (CK20) is an acidic keratin mainly present in gastrointestinal epithelial cells, which can participate in cell morphology maintaining and signal transduction by forming the cytoskeleton. In clinical practice, CK20 is mainly used to diagnose gastric cancer and colorectal cancer, and its expression level is positively correlated with the pathological grading and clinical staging of the tumor. Therefore, CK20 is considered as an independent risk factor for poor prognosis, speculated that it stimulates the proliferation and metastasis of cancer cells by participating in chromosome activity regulation or promoting epithelial-mesenchymal transition (EMT). Moreover, the characteristic that CK20 remains stably expressed after tumor spread makes it become an effective biomarker for micrometastases. Meanwhile, CK20 is not expressed in normal pancreas but can be expressed in pancreatic ductal carcinoma, and its positive patients have shorter survival time and higher recurrence rate. In addition, CK20 positive lung cancer, liver cancer, and ovarian cancer suggest that they may originate from gastrointestinal cancer.