[Expression of epidermal growth factor receptor (EGFR) in hormone-independent breast cancers]

To determine the expression of epidermal growth factor receptor (EGFR) in ER-negative and Pg-R negative infiltrating ductal carcinomas of the breast (IDC) and to analyze the possible relationship between the EGFR positivity and some clinico-biological parameters of tumors.

EGFR was measured by a single point radioligand assay in the cell surfaces of 115 ER-negative and Pg-R-negative (< 10 fmol/mg prot.) IDC. We measured also the cytosolic concentrations of pS2, cathepsin D, tissue-type plasminogen activator (t-PA) and hyaluronic acid (AH), as well as the levels of AH in cell surfaces. Tumor size, axillary involvement, distant metastasis, histological grading, ploidy and S-phase (SP) were taken account.

Using as cut-off for EGFR a value of 5 fmol/mg prot., we can observed that IDCs -EGFR + had greater global values of S-phase (p: 0.005) and were more frequently metastastatic (p: 0.004), SP > 7 % (p < 0.001) and SP > 14 % (p: 0.077); likewise, they were lower frequently pS2-positive (p < 0.01) and t-PA-positive (p < 0.01). During the follow up time (median 85 months), the number of recurrences was higher in EGFR-positive than in EGFR- negative tumors (14/41 frente a 1/29; p: 0.002), but there was not differences in the number of deaths by the tumor.

1) The EGFR-positivity in ER-negative and PgR-negative IDCs is associated with distant metastasis, greater cellular proliferation (SP), lower positivity for pS2 and t-PA and greater number of recurrences. 2) Using 10 fmol/mg prot. as cut-off, we observed the same findings, except the change in cellular proliferation. 3) Our findings support the possible use of EGFR as a prognostic parameter in those breast carcinomas.