As one of the most important oncogenes, EGFR alterations in the RTK-RAS pathway consistently manifest in multiple primary lung cancers, while PTEN mutations, as a tumor suppressor gene, within the RTK/PI3K/AKT pathway increase the risk of thyroid, breast, endometrial, colorectal cancer, and malignant melanomas (Figure 2B). Here, EGFR is linked to colorectal cancer.