IGF1 and thyroid gland undifferentiated (anaplastic) carcinoma: Similarly, Lv J. et al. demonstrated that M2 tumor-associated macrophages (TAMs) promote the invasiveness and stemness of anaplastic thyroid carcinoma (ATC) cells by secreting IGF-1 and IGF-2, thereby activating the IR-A/IGF1R-mediated PI3K/AKT/mTOR signaling pathway [32].