PCNP and neoplasm: As reported (a) PCNP is ubiquitinated by NIRF which is up regulated during tumor,22 (b) ubiquitin is involved in membrane trafficking and (c) the involvement of PCNP in apoptosis through DNA damage response and in chromatin dynamics via STAT phosphorylation,72 are important factors which evoke the PCNP involvement in cell cycle regulation, transcription and apoptosis.