Epidermal growth factor (EGF) stimulates the growth of several types of epithelial tissues and possesses a strong mitogenic activity that is mediated through its cell surface receptor (EGFR). The aim of this study was to characterize EGFR and measure its levels in head and neck tumors biopsies (70 patients); use of a simplified competition technique with a radiolabeled ligand allowed evaluation of functional EGFR. Five samples (4 tumors and 1 control) were used to characterize EGF binding. Graphic representation identified a single family of binding sites. Kd values revealed high affinity for EGF binding: mean Kd, 0.156 f 0.1 08 nM (0.095-0.347 nM). EGF-binding characteristics (Kd) tion was found between EGFR levels and tumor size and stage. Controls exhibited a trend toward higher EGFR levels in elevated sizes and stages. According to a cutoff EGFR value of 100 frnol/rng protein, which separated all controls from tumors, EGFR-positive tumors (>lo0 fmol/mg protein) had a greater probability of complete response to chemotherapy than EGFRnegative tumors; other tumor characteristics, such as the degree of tumoral differentiation, tumor size, or stage, were unable to operate such a discrimination in the response to chemotherapy. EGFR may thus be an interesting biological marker for head and neck cancer. HEAD & NECK 1991;13:132-139 were similar in nontumoral tissue samples (controls) and in tumor material. In 59 of 60 cases, EGFR levels were higher in the tumor than in the corresponding controls. A significant correla-
Epidermal growth factor (EGF
) is a growth factor polypeptide with a molecular weight of 6,000 daltons, which was described by Cohen' in the mouse submaxillary gland. EGF stimulates the growth of several types of epithelial tissues and diated through its surface receptor (EGFR)* The intracellular component of EGFR is very similar to the V-erb p oncogene product2 In human cancer, the presence of EGFR has been reported in the b r e a ~t , ~* ~ lung: bladder,6 brain,7 ovaries,' thyroid,' and aerodigestive tract.lO." In these localizations, EGFR has been measured directly, by ligand-binding methods, or indirectly,