IGF1 and breast cancer: IGF/IGF1R signaling has been reported to be involved in BM of multiple human cancers,41, 43, 44, 45, 46, 47, 48 and the PI3K/AKT and NF‐κB pathways are two downstream signaling pathways in IGF/IGF1R axis‐induced BM in PCa and breast cancer.46