ERBB2 and breast cancer: Consider the seven Luminal B and HER2+ cell lines present in the BC atlas, which by definition overexpress HER2: whereas more than 90% of cells in AU565, BT574 and HCC1954 cell lines express ERBB2, in the remaining four cell lines ERBB2 expression ranged from 31% of EVSAT cells to 46% of JIMT1 cells and up to 64% of MDA-MB-361 cells.