Epidermal growth factor receptor in human breast cancers: correlation with estrogen and progesterone receptors.

Epidermal growth factor receptor (EGFR), determined by the Scatchard curve method, was found in 22 cases of a random series of 100 patients with breast carcinoma. Two groups of patients were identified, one (n = 16) with a low concentration (0-50 fm/mg protein) of EGFR but with a high affinity (Kd = 3.2 nM), and the other (n = 6) with a high concentration (90-210 fm/mg protein) of EGFR but with a lower affinity (Kd = 6.3 nM). A significant inverse relationship was found between the presence of EGFR and receptors for estrogen (p less than 0.001) and progesterone (p = 0.001). EGFR was found in no (0/8) tumors with Grade I histoprognostic grade, 17% (10/58) Grade II, and 38% (11/29) Grade III (p less than 0.05). EGFR is present therefore in poorly differentiated tumors and associated with other factors of poor prognosis. Our in vivo analyses confirm results found in tissue culture derived from human breast carcinoma cells.