Considering that YAP enhances ER transactivation via WW domain binding protein-2 (WBP-2) [44] and that decreased expression of YAP is associated with ER and PR negativity in patients with invasive breast cancer [45], we speculate that YAP motility shift and the multisite phosphorylation of YAP induced by ABF only occur in MCF-7 cells, which are ER- and PR-positive. Here, WBP2 is linked to invasive breast carcinoma.