Epidermal growth factor receptors in breast cancer: association with early relapse and death, poor response to hormones and interactions with neu.
Harris AL., Nicholson S., Sainsbury JR., Farndon J., Wright C.
Epidermal growth factor receptors (EGFRs) were measured in 221 primary breast cancers by ligand binding with 125I-labelled EGF, and high-affinity sites were quantitated. There was a highly significant inverse relationship between oestrogen receptor (ER) and EGFR (15 EGFR-positive [EGFR+]ER+ and 92 EGFR-negative [EGFR-]ER+: 54 EGFR- ER- and 60 EGFR+ ER-). The relapse-free survival and overall survival were significantly shorter for EGFR+ vs EGFR- tumours (P less than 0.001) by about 2 yr in the case of relapse-free survival. When ER- tumours were substratified by EGFR status, the EGFR- ER- tumours had a prognosis almost as good as the ER+ tumours. In 31 of 184 cases, high expression of neu, correlating with amplification, was found. Expression of neu conferred similar poor prognosis to EGFR expression in all prognostic subgroups. Coexpression of neu and EGFR had an additive adverse effect. Epidermal growth factor receptors (EGFR) and oestrogen receptors (ER) were analysed in 221 patients with primary operable breast cancer by means of radioligand assays. After median follow-up of 24 months (range 3-60 months), there had been recurrences in 99 patients, of whom 72 (median age 56 yr, range 32-77 yr) received tamoxifen alone as first-line treatment for recurrence. 14 patients (19%) showed a response to this therapy and 58 (81%) did not. Of 32 ER+ tumours, 12 (37.5%) showed an objective response to tamoxifen compared with only 2 of 40 (5%) ER- tumours (P less than 0.005). Of 35 EGFR+ tumours, 3 (8.5%) achieved an objective response compared with 11 of 36 (30%) EGFR tumours (P less than 0.05). Only 1 of 28 EGFR+, ER- tumours achieved an objective response. Including patients whose disease remained stable for more than 6 months with the responders, however, EGFR status was a better predictor of response to tamoxifen; 15 of 37 EGFR- patients and 5 of 35 EGFR+ patients responded (P less than 0.01).