Increased YAP1 Expression is Significantly Associated with Breast Cancer Progression, Metastasis and Poor Survival

YAP1 plays a key role as a transcriptional coactivator in the Hippo pathway. Based on conflicting reports regarding YAP1 function in cancer, this study discerned its role in breast carcinogenesis. First, a systematic review of salient breast cancer studies targeting YAP1 dysregulation was performed. Additionally, freshly excised tumor specimens of approximately 200 breast cancer patients were processed for quantification of YAP1 expression at mRNA and protein levels using quantitative PCR and immunohistochemistry, respectively. YAP1 expression was nine folds higher in tumors versus controls and significantly associated with metastasis (p < 0.05) and poor survival in Pakistani breast cancer patients. These findings establish the role of YAP1 overexpression in tumorigenesis and metastasis. Hence, YAP1 inhibition may be considered a possible therapeutic strategy.Lay abstract Breast cancer incidence and prevalence are rapidly increasing across the globe, especially in countries with poor screening interventions, culminating in delayed diagnosis and greater mortality. Furthermore, for the adequate treatment of breast cancer, treatment plans must be individualized. In this context, the present study was devised to add to the existing pool of information with regard to breast cancer. In addition, the authors wanted to see whether YAP1 (the gene of interest) significantly contributes to breast cancer progression and its spread to distant areas of the body. Also, the authors aimed to study the effect of this gene on survival in breast cancer patients. Knowing the role of YAP1 in breast cancer, it is imperative to make use of this gene in devising treatment strategies for the proper management of breast cancer patients.