ERBB3 and breast carcinoma: Regarding the fact that HER3-mediated resistance occurs when using Hsp90 inhibitors such as AUY922 (62, 63), ZHER3:8698 affibody molecule was radiolabeled with 89Zr not only as an imaging radiotracer but also as a tool for evaluation of HER3 expression levels in breast cancer xenograft models.