title: Colorectal cancers differ in respect of PARP-1 protein expression.
abstract: Recent findings raise the possibility of PARP inhibitor therapy in colorectal cancers (CRCs). However, the extent of PARP-1 protein expression in clinical specimens of CRC is not known. Using immunohistochemistry we assessed PARP-1 protein expression in tissue microarrays of 151 CRCs and its association with the patient's age, sex, Astler-Coller stage, grade and site of the tumor. High PARP nuclear immunoreactivity was found in 68.2% (103/151) of all cases. In turn, 31.8% (48/151) of tumors showed low PARP expression, including 9 (6%) PARP-1 negative CRCs. There was a significant association of PARP-1 expression with the site of CRC and Astler-Coller stage. A high PARP expression was noted in 79.1% of colon vs. 53.9% of rectal tumors (p = 0.001). The mean PARP-1 score was 1.27 times higher in colon vs. rectal cancers (p = 0.009) and it was higher in stage B2 vs. stage C of CRCs  (p = 0.018). In conclusion, the level of PARP-1 protein nuclear expression is associated with the tumor site and heterogeneous across clinical specimens of CRC, with the majority of CRCs expressing a high level but minority - low or no PARP-1 expression. These findings may have a clinical significance because the assessment of PARP-1 expression in tumor samples may improve selection of patients with CRC for PARP inhibitor therapy.
authors.affiliation: Department of Clinical Oncology, Pomeranian Medical University, Szczecin, Poland.
authors.forename: Violetta
authors.initials: V
authors.lastname: Sulzyc-Bielicka
authors.forename: Paweł
authors.initials: P
authors.lastname: Domagala
authors.forename: Jolanta
authors.initials: J
authors.lastname: Hybiak
authors.forename: Anna
authors.initials: A
authors.lastname: Majewicz-Broda
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Safranow
authors.forename: Wenecjanusz
authors.initials: W
authors.lastname: Domagala
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis / Q000096:biosynthesis*; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases