Epidermal growth factor receptor in breast cancer: correlation of quantitative immunocytochemical assays to prognostic factors

Evaluation of the prognostic and predictive value of HER-1/EGFR in breast cancer patients participating in a randomized study with dose-dense sequential adjuvant chemotherapy

BACKGROUND

To assess the prognostic and predictive significance of HER-1/EGFR protein levels in high-risk patients with breast cancer treated with dose-dense sequential adjuvant chemotherapy.

METHODS

595 high-risk breast cancer patients were treated with adjuvant anthracycline-based dose-dense sequential chemotherapy (E-CMF vs. E-T-CMF). Disease-free survival (DFS) was the primary end point. HER-1/EGFR was assessed by immunohistochemistry (IHC) in 312 patients.

RESULTS

HER-1/EGFR expression was detected in 54 of 312 patients (17%). Positive expression of HER-1/EGFR was significantly associated with negative receptor status (52 vs. 17%, p < 0.001), worse histological grade (70 vs. 45%, p = 0.001), HER-2 overexpression (46 vs. 27%, p = 0.01) and positive p53 expression (48 vs. 19%, p < 0.001). With a median follow-up of 7 years, the total number of relapses was 105 (34%), and the total number of deaths 69 (22%). The analysis for DFS provides significant evidence that the HER-1/EGFR effect on the risk of disease progression was different according to treatment (interaction p = 0.02). Regarding overall survival, a trend towards a significant difference for an interaction of HER-1/EGFR and treatment was found (p = 0.07).

CONCLUSION

The present study demonstrated a differential effect of positive HER-1/EGFR expression in the two treatment groups, with HER-1/EGFR being a negative prognostic marker in the absence of paclitaxel.

Epidermal growth factor receptor expression in 780 breast cancer patients: a reappraisal of the prognostic value based on an eight-year median follow-up

PURPOSE

Because new therapeutic approaches target tumors expressing epidermal growth factor receptor (EGFR), the aim was to undertake a thorough analysis of the expression profile of EGFR in breast cancer and to reassess its prognostic value.

PATIENTS AND METHODS

Tumor EGFR levels were determined by a specific ligand binding assay in 780 consecutive breast cancer patients followed in our institute between 1980 and 1993. Mean age was 61 years (25-85 years). All patients had undergone tumor resection with axillary lymph node dissection: 373 patients (47.8%) underwent mastectomy, 37 (5%) subcutaneous mastectomy and 370 (47.2%) tumorectomy.

RESULTS

EGFR levels ranged between non-detectable up to 789 fmol/mg protein. EGFR median value was 9 fmol/mg protein and only a small proportion of patients exhibited a relatively marked EGFR expression. There was no link between tumor size, grade, node status and EGFR tumoral levels. There was a constant and significant decrease in EGFR tumoral levels according to patient age. A significant inverse relationship was found between estradiol receptors (ER) and EGFR. Median follow-up was 97 months with a minimum at 4 months and a maximum at 228 months. From univariate analysis it was found that histological grade, tumor size, node status and ER status were all significant predictors of survival, considering metastasis-free as well as overall survival. Using multivariable analysis, only histological grade, tumor size and node status remained independent predictors of survival.

CONCLUSION

EGFR determination is of limited value as a prognostic indicator in breast cancer.

The epidermal growth factor receptor in breast cancer

The epidermal growth factor receptor (EGFR)3 is a 170 kD transmembrane tyrosine kinase activated by several ligands. It is required for normal mammary development and lactation and is aberrantly expressed in approximately 40% of breast carcinomas, particularly those with a poor prognostic phenotype. Since EGF receptor levels are elevated in a high proportion of many tumor types its potential as a therapy target is being investigated using the EGF receptor to target toxins, as well as drugs that interfere with signaling and anti-receptor antibodies. These approaches are likely to be most effective when used in the adjuvant situation in combination with chemotherapy.

Oncogene proteins and proliferation antigens in thymomas: increased expression of epidermal growth factor receptor and Ki67 antigen

AIMS

To examine thymomas for proteins encoded by oncogenes and to determine whether their presence correlates with tumour growth and associated myasthenia gravis.

METHODS

Sections of 24 thymomas were incubated with anti-EGF receptor (EGF-R), anti-Ki67 antigen, anti-p53, and anti-bcl-2 antibodies, and then stained using the alkaline phosphatase/anti-alkaline phosphatase (APAAP) technique. Cell suspensions and epithelial cell cultures from some of the tumours were also studied.

RESULTS

Whereas EGF-R expression was not detected in any of the controls (but only in a 20 week old fetus), it was detected in neoplastic epithelial cells of all thymomas, and was most strongly expressed in metastases and in samples from donors with severe myasthenia gravis. Ki67 labelling was also increased, especially in the larger thymomas. Epithelial expression of both of these markers was confirmed in fresh cell suspensions and monolayer cultures from the five available cases. In contrast, p53 and bcl-2 were not detected in the neoplastic cells, but bcl-2 was present in the intermingling thymocytes.

CONCLUSIONS

Neoplastic thymoma cells express EGF-R and Ki67, but there is no concomitant increase in the expression of p53 and bcl-2 proteins. Increased EGF-R expression may result in increased proliferation of neoplastic cells and also in myasthenia gravis. Measurement of EGF-R concentrations may be of prognostic value. The bcl-2 staining pattern in T lymphocytes illustrates the broad spectrum of maturational stages in thymoma lymphocytes.

Platelet-derived growth factor (PDGF) and receptor (PDGFR) expression in human meningiomas: correlations with clinicopathological features and cytogenetic analysis

PDGFs and their receptors expression were examined in a series of 46 meningiomas by using specific monoclonal antibodies. The immunostaining was quantified by an image analyser and the results correlated with clinical and morphological data (histological type and grade). In addition, since the PDGFB chain is encoded by the c-sis proto-oncogene localized on chromosome 22 and because monosomy 22 has been frequently reported in meningiomas, PDGFs and PDGFRs expression have been correlated with cytogenetic analysis performed in 29 cases. The results demonstrate PDGF A and PDGF B expression in most meningioma specimens and co-expression of these growth factors in numerous cells. PDGF A and B immunoreactivity was related to histological grade. PDGFR beta expression was strong in almost all meningiomas whereas PDGFR alpha was low. PDGFR alpha expression was related to tumour location and grade and PDGFR beta to histological subtype only. The cytogenetic analysis was not related to PDGFB chain expression. Taken together these data further confirm PDGF and PDGFR expression in human meningioma; PDGF may exist as an heterodimer (AB) as well as its receptor. The lack of correlation between cytogenetic analysis and PDGF values, the low level of PDGFB in recurrent meningiomas suggests that it is unlikely that the c-sis proto-oncogene plays an important role in the genesis of meningiomas.