IGF1 and glioblastoma: Notably, EGFR signaling is associated with IGF-IR expression and IGF-I secretion in cancer cells [54,55], contributing to cancer cell growth and poor survival; thus, dual targeting at EGFR and the IGF/IR axis has been suggested to be a promising therapeutic strategy for overcoming drug-acquired resistance in several cancer types, such as lung adenocarcinoma, head and neck squamous cell and colorectal carcinomas, and glioblastoma [55,56,57,58].