Our findings indicate that nPARP1 expression is an independent factor for sporadic BCs and PARP1 inhibitors could be a promising therapy for different phenotypes.
In this study, the expression of BER enzymes (redox factor 1/apurinic-apyrimidinic endonuclease 1 (REF1/APEX1), NTH endonuclease III-like 1 (NTHL1), 8-oxoguanine DNA glycosylase (OGG1), PARP1) and of the scaffold protein XRCC1 (X-ray repair complementing defective repair in Chinese hamster cells 1) were investigated in familial (BRCA-related and not) and sporadic breast cancer cases.
Loss of BRCA1 in sporadic breast cancer suggests that therapeutics targeting BRCA1 pathway in hereditary breast cancer like PARP inhibitors might be used as therapeutic targets for sporadic breast tumours.
In familial breast cancer, a combination of high cPARP and high nPARP expression is the most common (33 %), whereas in sporadic breast cancer, a combination of low cPARP and intermediate nPARP expression is the most common (39 %).