ERBB2 and breast cancer: Previous studies have shown that in breast cancer cells, IR‐stimulated HER2‐mediated PI3K‐AKT signaling activates NF‐κB to induce RelA‐mediated HER2 transcription, which further boosts AKT‐NF‐κB signaling.[31, 45] Moreover, IR also activated HER2‐ERK signaling.