MKI67 and neoplasm: High nuclear YAP1 expression was associated with hormone receptor negativity and aggressive tumor behavior, including lymph node metastasis, high Ki67 labeling index and inferior distant metastasis-free survival (DMFS, hazard ratio [HR] 2.271, 95% confidence intervals [CIs] 1.109–4.650, P = 0.0249), and also confirmed inferior disease free survival (HR 3.208, 95% CIs 1.313–7.833, P = 0.0105) in external validation cohort.