Cytokeratins, a group of intermediate filament proteins, have potential molecular mechanisms involving epithelial cell differentiation, tumor invasion, and metastasis, making them valuable biomarkers for cancer diagnosis and prognosis; currently, cytokeratin-based assays, such as CK19 for detecting disseminated tumor cells, are utilized in clinical practice for assessing the presence of minimal residual disease and predicting treatment response in various cancer types, including CRC. This evidence concerns the gene KRT19 and cancer.