EGFR and neoplasm: To mimic a heterogeneous tumor cell population, in the next set of experiments, GL261/EGFR and GL261/ErbB2 cells were mixed at a 1:1 ratio, and then co-cultured for 3 h with NKAR-NK cells in the absence or presence of 0.16 nM (25 ng/mL) of the individual NKAB proteins, or a combination of 0.08 nM (12.5 ng/mL) of NKAB-EGFR and NKAB-ErbB2.