C-myc oncoprotein expression and gene amplification in apocrine metaplasia and apocrine change within sclerosing adenosis of the breast
ABSTRACT Overexpression and/or amplification of c-myc oncogene are known to occur in human breast carcinomas, particularly those of high grade. Apocrine metaplasia (APM) is a common finding within fibrocystic change, and in some cases appears to be associated with an elevated risk of subsequent breast cancer. It has been suggested that apocrine metaplasia within sclerosing adenosis of the breast, also called apocrine adenosis (AA), has a premalignant potential. Little, however, is known about cellular level genetic alterations in either APM or AA of the breast. Because of this, c-myc expression and amplification in APM and AA were studied. Fluorescence in situ hybridisation (FISH) is a methodological approach to detecting these genetic alterations. In this study, APM and AA were studied immunohistochemically to detect c-myc oncoprotein expression, and FISH was employed using a DNA probe for the c-myc gene in archival tissue sections of cases of APM and AA of the breast. Nuclear immunostaining for c-myc was seen in all APM and AA cases studied, but amplification of the c-myc gene was not seen in any cases with APM or AA. The results of this study indicate that c-myc overexpression appears to occur early in breast oncogenesis. Amplification of the c-myc gene does not occur in APM or AA of the breast, however, suggesting that this particular genetic alteration constitutes a late event in the pathogenesis of breast carcinomas.
SourceAvailable from: Semir Vranic[Show abstract] [Hide abstract]
ABSTRACT: Apocrine carcinoma of the breast is a rare, special type of breast carcinoma showing distinct morphologic, immunohistochemical and molecular genetic features. Apocrine epithelium has a characteristic steroid receptor profile that is estrogen receptor and progesterone receptor negative and androgen receptor positive. This combination of morphologic and immunohistochemical characteristics is essential for the proper recognition of the apocrine carcinomas. Strictly defined, apocrine carcinomas express either Her-2/neu or EGFR, which along with androgen receptor positivity make patients with the apocrine carcinoma eligible for targeted therapies.Histology and histopathology 06/2013; 28(11):1393-1409. · 2.24 Impact Factor
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ABSTRACT: Background The c-myc proto-oncogene plays a central role in the regulation of cellular transcription, differentiation, and apoptosis, and has been shown to be deregulated in many types of human cancer. Recent findings have demonstrated its amplification in select vascular neoplasms, such as secondary angiosarcomas, suggesting a role in angiogenesis as well. In vitro studies have shown that the c-Myc protein is an important regulatory molecule of spindle cell proliferation and migration in Kaposi's sarcoma (KS). Objectives In light of these findings, our primary aim was to ascertain whether c-myc, by promoting proliferation and angiogenesis, is an essential co-factor in the aetiopathogenesis of KS. We also attempted to determine a correlation between immunohistochemical expression of the c-Myc protein and c-myc gene copy amplification using fluorescent in situ hybridization (FISH). Methods Samples analyzed included archival tissue of KS (n = 24). PCR for detection of Kaposi's sarcoma-associated herpesvirus DNA was performed on all samples of KS. For FISH analyses, a dual-labelled technique was employed and probes for the c-myc gene and chromosome 8 were used. The monoclonal anti-c-myc antibody, 9E10, was used for immunohistochemical analyses. Results While FISH analyses revealed no amplification of c-myc in any of the cases of KS, immunohistochemical analyses revealed positive staining for c-Myc in 13/24 cases (54%). Conclusions Amplification of the c-myc gene was not witnessed in this preliminary study of 24 cases and thus cannot be correlated with the expression of the c-Myc protein.Journal of the European Academy of Dermatology and Venereology 08/2012; 28(1). DOI:10.1111/j.1468-3083.2012.04672.x · 3.11 Impact Factor
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ABSTRACT: The c-myc proto-oncogene is involved in various cellular processes including cell growth, proliferation, and apoptosis. Overexpression and deregulated expression of the gene have been previously linked to several lineage-unrelated, aggressive, and poorly differentiated tumors. The expression of c-myc has also been implicated in hematopoiesis and has been shown to play a crucial role in angiogenesis via a vascular endothelial growth factor-dependent mechanism. This gives c-myc a dual oncogenic function in that tumor growth requires both cell proliferation and angiogenesis to ensure survival and confer an effective malignancy. Amplification of c-myc has been recently reported to be a recurrent genetic alteration in angiosarcomas secondary to irradiation and/or chronic lymphedema. Of note, however, no c-myc gene abnormalities have been demonstrated in cases of primary angiosarcomas or postradiation atypical vascular lesions. More recently, our own experience indicates that c-myc amplification is not normally found in the Kaposi sarcoma and cannot be correlated with expression of the c-Myc protein. This comprehensive review outlines the structure, normal functions, and effects of the deregulated expression of c-myc with particular emphasis on its role in angiogenesis and select cutaneous vascular neoplasms.The American Journal of dermatopathology 12/2012; DOI:10.1097/DAD.0b013e31827aad83 · 1.43 Impact Factor