Wykosky et al. created ephrin-A1-PE38QQR, a novel cytotoxin composed of the EPHA2 ligand ephrin-A1, and PE38QQR, a mutated form of Pseudomonas aeruginosa exotoxin A, and concluded that this ephrin-A1-based cytotoxic therapy specifically acts through the EPHA2, and exhibits potent cytotoxic effects on MDA-MB-231 BC cells [33]. Here, EFNA1 is linked to breast cancer.