Relationship between epidermal growth factor receptor (EGF-R) and various prognostic factors in human endometrial carcinoma

Abstract

Eighty primary endometrial carcinomas were analyzed for the presence of epidermal growth factor receptors (EGF‐R) by the use of a single point (1ng 125I‐EGF) EGF‐R assay. Fifty percent of the analyzed specimens were EGF‐R positive (EGF‐R(+)) with binding capacities > 1 fmol mg−1 and 15% bound > 7 fmol mg−1. The EGF‐R status was correlated with different clinically relevant prognostic factors and the survival rates were analyzed. The correlations revealed no significant differences in the grade of tumor differentiation and in the depth of myometrial invasion. The advanced tumor stages III and IV and tumors with a squamous cell component in the histologic examination expressed EGF‐R in a higher percentage. Between the EGF‐R and the steroid receptor status existed a weak negative correlation. Estrogen receptor positive tumors were in 47% and progesterone receptor positive tumors in 45% EGF‐R (+). The corresponding number for the receptor negative tumors were 57 and 65%. Life table analyses were performed with different cut‐off limits for specific EGF binding ranging from > 1, > 3, > 5 and > 7 fmol mg−1. Dependent on the cut‐off limits the analysis demonstrates a reduced survival probability for patients with EGF‐R+ tumors. These differences were mainly found in the small group with a high number of EGF‐R’s (> 7 fmol). The analysis of tissue extracts for the presence of factors binding to the EGF‐R revealed in some specimens high concentrations of EGF‐like factors. By the use of TGFa (transforming growth factor alpha) immunohistochemistry we were able to demonstrate that the tumor cells produce TGFa, whereas the stroma is TGFa negative. We assume that the EGF‐like factors consist mainly of TGFa.