HER2/neu (ErbB2, c-erbB2, p185HER2)

Specificity: Human epidermal growth factor receptor 2.

Staining characteristics: Strong cell membrane staining around the entire cell is associated with gene amplification.

Function: Human epidermal growth factor receptor 2 is one of the family of ((EGFR|epidermal growth factor (EGFR) receptors)) used primarily in characterizing breast adenocarcinomas. In breast it is associated with poor prognosis and high histologic grade; 85% concordance between immunohistochemistry and FISH, though some laboratories are moving to FISH exclusively. It is often also amplified in ADH and DCIS, suggesting involvement in initiation of breast carcinogenesis, as well as vulvar Pagets disease.

A monoclonal antibody to HER2/neu (trastuzumab, aka Herceptin) has also been licensed for the treatment of advanced breast cancers that overexpress this receptor.

Normal cell distribution: None, it is a proto-oncogene on #17q11 to 17q21.

HER2/neu+: Subpopulations of:

• Breast adenocarcinoma
• Breast ADH
• Breast DCIS
• vulvar Pagets disease

HER2/neu-:

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