E2F1 and malignant colon neoplasm: Additionally, KRT23 can be used as an HCC-associated antigen in patient sera.14 At the molecular level, the expression of some genes (e.g., cyclin D1, cyclin E and E2F1) is decreased when KRT23 is knocked down.13 Additionally, KRT23 knockout colon cancer cells are restricted in their assembly of functional G1/S complexes.34