Erschienen in:
01.07.2014 | Preclinical study
Adverse prognostic and predictive significance of low DNA-dependent protein kinase catalytic subunit (DNA-PKcs) expression in early-stage breast cancers
verfasst von:
Tarek Abdel-Fatah, Arvind Arora, Devika Agarwal, Paul Moseley, Christina Perry, Nicola Thompson, Andrew R. Green, Emad Rakha, Stephen Chan, Graham Ball, Ian O. Ellis, Srinivasan Madhusudan
Erschienen in:
Breast Cancer Research and Treatment
|
Ausgabe 2/2014
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Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a serine threonine kinase belonging to the PIKK family (phosphoinositide 3-kinase-like-family of protein kinase), is a critical component of the non-homologous end-joining pathway required for the repair of DNA double-strand breaks. DNA-PKcs may be involved in breast cancer pathogenesis. We evaluated clinicopathological significance of DNA-PKcs protein expression in 1,161 tumours and DNA-PKcs mRNA expression in 1,950 tumours. We correlated DNA-PKcs to markers of aggressive phenotypes, DNA repair, apoptosis, cell cycle regulation and survival. Low DNA-PKcs protein expression was associated with higher tumour grade, higher mitotic index, tumour de-differentiation and tumour type (ps < 0.05). The absence of BRCA1, low XRCC1, low SMUG1, low APE1 and low Polβ was also more likely in low DNA-PKcs expressing tumours (ps < 0.05). Low DNA-PKcs protein expression was significantly associated with worse breast cancer-specific survival (BCSS) in univariate and multivariate analysis (ps < 0.01). At the mRNA level, similarly, low DNA-PKcs was associated with poor BCSS. In patients with ER-positive tumours who received endocrine therapy, low DNA-PKcs (protein and mRNA) was associated with poor survival. In ER-negative patients, low DNA-PKcs mRNA remains significantly associated with adverse outcome. Our study suggests that low DNA-PKcs expression may have prognostic and predictive significance in breast cancers.