[Epidermal growth factor receptor in human breast cancer: correlation with steroid receptors, tumor stage, grading...

In this study, correlations between the epidermal growth factor receptor (EGF-R), steroid receptors, and other prognostic parameters (grading, pTNM-status, menopausal status) were analysed in 326 primary breast carcinomas. 19% of the tumour samples were EGF-R positive, 63% were estrogen receptor (ER) and 54% progesteron receptor (PR) positive. Both steroid receptors were positive in 46% of all samples. We found a highly significant inverse correlation between EGF-R and steroid receptors. 88% of the ER positive tumours were EGF-R negative (p less than 5 x 10(-5)), 90% of the PR positive tumours were EGF-R negative (p less than 5 x 10(-5)) and 91% of the ER plus PR positive tumours were ERF-R negative (p less than 1 x 10(-6)). Grading was available in 170 cases. Six (4%) of the carcinomas were highly differentiated (G1), 82 (48%) were classified as G2, and another 82 (48%) were poorly differentiated (G3). A combination of negative ER and positive EGF-R was found more often in the population of G3 tumours. EGF-R was also positively correlated to tumour size. With regard to receptor status, we did not find a correlation with lymph node involvement. The ER correlated negatively (p less than 1.3 x 10(-5) and the EGF-R positively (p less than 0.042) with menopausal status. Thus, EGF-R overexpression seems to be a marker of morphological and functional dedifferentiation which is associated with a loss of steroid dependency and an increase of an autostimulatory-paracrine growth control. These changes seem to be related to poor prognosis.