Expression of epidermal growth factor receptors (EGFR) on breast carcinomas in relation to growth fractions, estrogen receptor status and morphological criteria. An immunohistochemical study.

Epidermal growth factor receptor (EGFR) expression was determined on 88 primary breast carcinomas immunohistochemically. These results were compared with growth fractions (Ki-67 immunoreactivity and Transferrin receptor (TrfR) expression), histologic tumor type, tumor grading, axillary lymph node status and estrogen receptor (ER) status. 60.2% were EGFR positive. Cytomorphology predominantly revealed a fine granular staining pattern. Sometimes a concentrated immunoreaction on the intercellular and basal oriented cell poles could be observed. EGFR expression in relation to growth fractions, grading, tumor diameter and lymph node status showed no correlation, suggesting that EGFR status seems to be independent to tumor growth and morphological prognostic parameters. ER status revealed an inverse correlation to EGFR expression (Kendall's tau: -0.22804, p = 0.012). In this context, it stands to reason to investigate further how far determination of EGFR expression justifies the existence of different subpopulations of breast cancer cells with respect to prognostic value.