ERBB2 and neoplasm: Before performing the co-culture with SKBR3 tumor cells, we pre-treated eNK cells with cytochalasin-D (CytD) for inhibition of actin recruitment, or incubated the cells in the presence of PP2 for inhibition of Src-tyrosine kinase, which resulted in a decrease of HER2 acquisition by NK cells (Figure S4A).