EGFR and neoplasm: Activation of overexpressed oncogenes (e.g. RAS and epidermal growth factor receptor (EGFR)) and loss of tumour suppressor genes (e.g. PTEN) leads to constitutive activation of the phosphatidyl inositol 3-kinases (PI3K)/AKT pathway that can enhance radioresistance of a various number of cancers (Ref.