These results match those observed in cytotoxicity experiments, with ELISA from MCF-7 targets used in cytotoxicity assays with 4B-21 showing increased MICA secretion under hypoxia that fits with the observed resistance to γδTc cytotoxicity in Figure 6A. Likewise, no difference in MICA secretion was observed in MCF-7 targets under 20 or 2% O2 subject to cytotoxicity assays with γδTc culture 10B-21, which also showed no MCF-7 resistance to γδTc killing in Figure 6B. Thus, resistance to γδTc killing appears to be correlated with MICA secretion by breast cancer targets. Here, MICA is linked to breast cancer.