Werner Syndrome Protein Expression in Breast Cancer

Werner protein (WRN) is a DNA helicase involved in genomic stability and commonly inactivated in breast tumors. Its clinicopathologic significance was investigated in a cohort of clinically annotated series of sporadic (n [ 1650) and BRCA-mutated (n [ 75) invasive breast tumors. Low WRN expression was associated with worse survival and aggressive molecular phenotype. Low WRN expression in topoisomerase-I-overexpressed tumors was also associated with poor survival. These findings can be used to optimize personalized treatment. Introduction: Werner protein (WRN) plays an important role in DNA repair, replication, transcription, and consequently genomic stability via its DNA-helicase and exonuclease activity. Loss of function of WRN is associated with Werner syndrome (WS), which is characterized by premature aging and cancer predisposition. Malignancies that are commonly linked toWSare thyroid carcinoma, melanoma, breast cancer, meningioma, and soft tissue and bone sarcomas. Currently, the clinicopathologic significance of WRN in breast cancer is largely unknown. Patients and Methods: We investigated the clinicopathologic and prognostic significance of WRN protein expression in a cohort of clinically annotated series of sporadic (n = 1650) and BRCA-mutated (n = 75) invasive breast cancers. We correlated WRN protein expression to clinicopathologic characteristics, DNA repair protein expression, and survival outcomes. Results: There is strong evidence of association between low nuclear and cytoplasmic WRN co-expression and low levels of KU70/KU80, DNA-PK, DNA Pol-B, CKD18, cytoplasmic RECQL4, and nuclear BLM protein expression (adjusted P-values <.05). Tumors with low nuclear or cytoplasmic WRN expression have worse overall breast cancer-specific survival (BCSS) (adjusted P-values < .05). In topoisomerase I overexpressed tumors, low WRN nuclear expression was associated with poor BCSS (P-value < .05). In BRCA-mutated tumors, low WRN cytoplasmic expression conferred shortest BCSS (P < .05). Conclusions: Low WRN protein expression is associated with poor BCSS in patients with breast cancer. This can be used to optimize the risk stratification for personalized treatment. (C) 2020 Elsevier Inc. All rights reserved.