MTOR and neoplasm: Cancer cells can directly expel drugs from the cells via exosomes.[34,46] Additionally, exosomes can also induce tumor drug resistance by modulating T lymphocytes, macrophages, and other cells.[47] Exosomes contribute to the development of drug resistance in tumor cells by regulating critical signaling pathways such as PI3K–AKT–mTOR, TGF-β, NF-κB, and Bcl-2/Bax.[48–50] Among these pathways, PI3K–AKT–mTOR is a pivotal regulator of cellular growth, proliferation, and metabolism.