MTOR and neoplasm: First-generation EGFR tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, reversibly bind to and inhibit the tyrosine kinase domain of EGFR, thus blocking the downstream RAS-RAF-MEK-ERK and PI3K-AKT-mTOR pathways (28–30), and inhibiting tumor cell proliferation (31, 32).