Epidermal growth factor is a growth factor that stimulates cell growth, proliferation, and differentiation by binding to its receptor EGFR. EGFR is a receptor tyrosine kinase activating several signaling cascades. It is ubiquitously expressed and observed in tumors of head and neck, brain, bladder, stomach, breast, lung, endometrium, cervix, vulva, ovary, esophagus, stomach, and in squamous cell carcinoma. Overexpression of EGFR in tumors indicates poor prognosis. The antibody detects both EGFR phosphorylated on Tyr1068 of the mature human isoform 1 (corresponding to Y1092 from the precursor form P00533-1/p170), and also unphosphorylated EGFR.