HER2 And EGFR Expression In Breast Cancers And Corresponding Loco-regional Recurrences: Therapeutic Implications

Background:The level and stability of expression in both primary tumors and corresponding metastases is crucial in the assessment of a receptor as target for diagnosis and therapy. Published data regarding the HER2 and EGFR receptor status in corresponding loco-regional recurrent lesions of breast cancers are rare. The goal of this study was to evaluate the expression of these receptors, and its stability during breast cancer recurrence and metastasis.Methods:Expression of EGFR and HER2 was investigated immunohistochemically in both loco-regional recurrences and corresponding primary breast cancers (n=19). HER2 and EGFR expression was scored using HercepTest criteria (0,1+,2+ or 3+).Results:HER2 overexpression (2+ or 3+) was found in 63.16%(12/19) of the primary breast cancers and 57.90%(11/19) of the corresponding loco-regional recurrences. There was a good concordance between the primary tumors and the paired recurrences regarding HER2 expression. Three patients who had 2+ or 3+ in the primary tumors changed to 0 or 1+ in loco-regional recurrences, and another two cases changed the other way around. A tendency for lower EGFR positivity in the recurrences was found in our cases.Conclusion:The HER2 expression seems to be stable during breast cancer recurrence. So, it seems that HER2 expression in the primary tumors can predict HER2-positive recurrences with a reasonably high probability. EGFR expression should be detected with recurrent lesion.