Although YAP1 is usually identified as an oncoprotein with functions of enhancing the tumor cells survival, migration, tumor angiogenesis, and chemotherapy resistance, some literature supports the idea that YAP1 functions as a tumor suppressor in cancers, for instance, head and neck cancers (HNC) [34], breast cancer [35], hematological malignancy [36], and CRC [5]. This evidence concerns the gene YAP1 and breast cancer.