CHOP,also known as GADD153 or DDIT3,is a highly conserved gene in both the structural and regulatory regions to hamster gene.Imposed by unfolded and malfolded proteins,CHOP is significantly induced by ER stress,deficiency of CHOP prevents cell from ER stress. CHOP is considered a proapoptotic marker of ER stress dependent cell death. CHOP acts as a dominant-negative inhibitor of the transcription factor C/EBP and LAP by forming a heterodimer. It may play an important role in the malignant transformation of nevus to melanoma.