STAT3 and neoplasm: Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) [53] enhance stemness and favor a pro-tumoral and pro-metastatic state by releasing cytokines (e.g., IL-6) that activate STAT3, ultimately inducing several stem-related pathways, EMT, and the expression of CSC markers, such as CD133 [54].