In addition, Weigelt et al. have shown that the response of the HER2-amplified breast cancer cell lines SKBR3, AU565, and HCC1569 to anti-HER2 agents trastuzumab, pertuzumab, and lapatinib was highly cell line dependent and dependent on whether the cells were cultured on 3D extracellular matrix gels or in 2D monolayers [10]. The gene discussed is ERBB2; the disease is breast carcinoma.