ERBB2 and breast cancer: Further tests on breast cancer cell lines expressing epidermal growth factor receptor (EGFR) and HER2 at different levels demonstrated that GA1CAR T cells released IL-2 when engaged through anti-HER2 FabLRT and cocultured with SKBR3 cells (P < 0.05), but not with MDA-MB-468 cells (Fig. 3E) that lack HER2 (fig.