KIAA0101, also known as p15(PAF), is a proliferating cell nuclear antigen-associated factor which interacts with proliferating cell nuclear antigen(PCNA). It was initially isolated in a yeast two-hybrid screen for PCNA binding partners, and was shown to bind PCNA competitively with the cell cycle regulator p21(WAF). KIAA0101 is localized primarily in the nucleus. It shares the conserved PCNA binding motif with several other PCNA binding proteins including CDK inhibitor p21 . KIAA0101 is involved in cell proliferation and plays a role in early tumor recurrence (ETR), and prognosis of hepatocellular carcinoma (HCC). KIAA0101 is expressed predominantly in liver, pancreas and placenta. It cannot be detected in heart or brain. It is highly expressed in a number of tumors, especially esophageal tumors, in anaplastic thyroid carcinomas and in non-small-cell lung cancer lines. Overexpression of KIAA0101 predicts high stage, early tumor recurrence, and poor prognosis of hepatocellular carcinoma. It also may be involved in protection of cells from UV-induced cell death.
