Stains
PARP

Author: Nat Pernick, M.D. (see Authors page)

Revised: 2 December 2015, last major update June 2005

Copyright: (c) 2002-2015, PathologyOutlines.com, Inc.

PubMed Search: PARP [title]

Definition / General
  • Poly (Adenoside diphosphate Ribose) Polymerase, a nuclear enzyme
  • Involved in DNA repair, genome surveillance and integrity, predominantly in response to environmental stress
  • Inhibits the Ca / Mg dependent endonuclease
  • An immediate cellular reaction to DNA strand breakage induced by alkylating agents, ionizing radiation or oxidants
    • May then mediate DNA base-excision repair
    • Also is an early step in apoptosis due to cleavage by CPP32 (caspase 3), which may lead to loss of its inhibitory effect, promoting apoptosis
Positive Staining - Normal
  • Melanoma (37%)
Negative Staining
  • Normal melanocytes (only scattered, focal staining)
Additional References