Vadevoo et al. reported that they synthesized an IL4R-targeting peptide (IL4RPep-1-K) conjugated with the proapoptotic peptide (KLAKLAK)2 and demonstrated this peptide exerted the selective anti-cancer effect against IL4R-expressing tumor in vitro and in vivo (4T1 breast tumor-bearing mice model) [11]. Here, IL4R is linked to cancer.