One patient with both HER2 amplification and ERBB3 mutation never progressed on therapy, but treatment was discontinued after 10.3 months as a result of depressed ejection fraction.
To this end, protein expression of EGFR, HER2 and HER3, and HER2 gene amplification was assessed by immunohistochemistry and silver in situ hybridization, respectively, on tissue microarrays with tumours from 175 periampullary adenocarcinomas, with follow-up data on recurrence-free survival (RFS) and overall survival (OS) for up to 5 years.
In breast cancer, the partnership of ERBB2 and ERBB3 may be crucial for the aggressive properties of cancers with ERBB2 amplification, and may contribute to pre-existing and acquired resistance to therapy.
In this study, we examined Her-1, Her-2, and Her- 3 protein expression as well as the frequency of Her-2 amplification in a series of 103 high-grade, advanced-stage (FIGO stage III or IV) ovarian surface epithelial carcinomas.
We found the mean AGCNs of the oncogenes equal 1.18 for erbB-1 [amplification was found in 11/35 cases (31%) and deletion in 6/35 cases (17%)], 2.00 for erbB-2 [amplification was found in 8/34 cases (24%), no deletion was found], 1.36 for erbB-3 [amplification was found in 4/36 cases (11%) and deletion in 1/36 cases (3%)], and 1.22 for erbB-4 [amplification was found in 5/30 cases (17%) and deletion in 1/30 cases (3%)].
Breast carcinoma cells with HER-2 gene amplification (21 MT-1 cells) and normal mammary epithelial cells without HER-2 gene amplification from the same patient (H16N-2 cells) were infected with pCMV-dn3 and assessed for HER-2/ HER-3 receptor tyrosine phosphorylation, p85PI 3-kinase and SHC protein activation, growth factor-dependent and -independent proliferation, and transformed growth in culture.
Phosphatidylinositol 3-kinase recruitment by p185erbB-2 and erbB-3 is potently induced by neu differentiation factor/heregulin during mitogenesis and is constitutively elevated in growth factor-independent breast carcinoma cells with c-erbB-2 gene amplification.