ErbB-2 nuclear function in breast cancer growth, metastasis and resistance to therapy

    1. Roxana Schillaci
    1. Laboratory of Molecular Mechanisms of Carcinogenesis, Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina
    1. Correspondence should be addressed to P V Elizalde; Email: patriciaelizalde{at}ibyme.conicet.gov.ar

    Abstract

    Approximately 15–20% of breast cancers (BC) show either membrane overexpression of ErbB-2 (MErbB-2), a member of the ErbBs family of receptor tyrosine kinases, or ERBB2 gene amplification. Until the development of MErbB-2-targeted therapies, this BC subtype, called ErbB-2-positive, was associated with increased metastatic potential and poor prognosis. Although these therapies have significantly improved overall survival and cure rates, resistance to available drugs is still a major clinical issue. In its classical mechanism, MErbB-2 activates downstream signaling cascades, which transduce its effects in BC. The fact that ErbB-2 is also present in the nucleus of BC cells was discovered over twenty years ago. Also, compelling evidence revealed a non-canonical function of nuclear ErbB-2 as a transcriptional regulator. As a deeper understanding of nuclear ErbB-2 actions would be crucial to the disclosure of its role as a biomarker and a target of therapy in BC, we will here review its function in BC, in particular, its role in growth, metastatic spreading and response to currently available MErbB-2-positive BC therapies.

    Keywords
    • Received 3 October 2016
    • Accepted 6 October 2016
    • Made available online as an Accepted Preprint 7 October 2016
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