Abnormal activation of the EGFR tyrosine kinase domain activates downstream signaling pathways, including the rat sarcoma virus oncogene homolog (RAS)/rapidly accelerated fibrosarcoma (RAF)/MAPK/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mTOR pathways, leading to the malignant proliferation of tumor cells. This evidence concerns the gene EGFR and neoplasm.