ERBB2 and breast carcinoma: To test whether this feedback also contributes to MAPK signaling robustness in a disease‐relevant system, we evaluated its function in MCF10A cells, a breast epithelium model, using either wild‐type (WT) or overexpressing ErbB2 (referred to as ErbB2over) recapitulating the ErbB2 amplification observed in 20% of all breast cancers (Yarden & Pines, 2012; Arteaga & Engelman, 2014).