The HER2 protooncogene encodes a 185-kD transmembrane phosphoglycoproteins, human epidermal growth factor receptor 2 (p185HER2), whose amplified expression on the cell surface can lead to malignant transformation.
We investigated by immunohistochemistry expressions of topoisomerase alpha II, MIB-1, p53, p21, E-cadherin, retinoblastoma (RB) gene protein product, HER-2/neu, and steroid hormone receptors in a case of juvenile respiratory papillomatosis with malignant transformation to determine whether these markers are associated with malignant transformation.
The decreased expression of nm23 protein and increased expression of c-erbB-2 protein are strong predictors for the malignant transformation of complete mole.
Our results indicate that the cell motility enhancing effect of HER-2/neu oncoprotein and possibly vimentin plays a significant role in the pathogenesis of MPD which appears to be a pagetoid spread of an underlying ductal malignancy (secondary), while EPD is an in situ malignant transformation of a totipotential epidermal cell or glandular epithelium.
These findings may be of particular interest because the transition from high grade intraepithelial neoplasia to invasive carcinoma is a crucial step in malignant transformation in Barrett's carcinogenesis and might underline the putative role of GRB7 and ERBB2 in cell migration and tumor invasion.
Remarkably, pharmacological FAS blockade using the mycotoxin cerulenin or the novel small compound C75 completely suppressed the state of Her-2/neu-induced malignant transformation by inhibiting the ability of NIH-3T3/Her-2 cells to grow under either anchorage-independent (i.e., to form colonies in soft agar) or low-serum monolayer conditions.
We propose a multistep model for the process of malignant transformation by ERBB2 wherein secondary lesions either target P21 or downstream effectors of senescence to bypass this primary fail-safe mechanism.
Because the development of an in vitro model of malignant transformation can provide a powerful new tool for establishing critical events governing the molecular pathogenesis of cholangiocarcinoma, we investigated the potential of achieving malignant transformation of cultured rat cholangiocytes in relation to aberrant overexpression of mutationally activated erbB-2/neu.
These results support the hypothesis that UVA enhances the expression of ErbB2 via cAMP- and protein kinase-dependent AP-2 alpha activation in keratinocytes, which may serve as a key mechanistic basis for the malignant transformation of keratinocytes exposed to UVA irradiation.
Collectively, our results identify HMGA2 and MDM2 as amplification targets in PA and Ca-ex-PA and suggest that amplification of 12q genes (in particular MDM2), deletions of 5q23.2-q31.2, gains of 8q12.1 (PLAG1) and 8q22.1-q24.1 (MYC), and amplification of ERBB2 may be of importance for malignant transformation of benign PA.
Genetic alterations of the proto-oncogene human epidermal growth factor receptor (HER-2/neu) have been shown to induce malignant transformation and metastasis.
Extra-virgin olive oil polyphenols inhibit HER2 (erbB-2)-induced malignant transformation in human breast epithelial cells: relationship between the chemical structures of extra-virgin olive oil secoiridoids and lignans and their inhibitory activities on the tyrosine kinase activity of HER2.
The molecular profiling of HNEpi breast tissue revealed gene expression abnormalities that may represent potential markers of increased risk for HER2‑positive malignant transformation of breast tissue, and may be able to be employed as predictors of prognosis.
One of the keys for targeting ERBB2 will be to consider the entire ERBB family and downstream associated pathways responsible for the malignant transformation.