ERBB2/HER2 Alterations in Cancer

    • HER2 (ERBB2) is the second member of the EGFR family receptors.
    • HER2 heterodimerizes with EGFR as well as ERBB3.
    • ERBB2/HER2 is often overexpressed/amplified in various cancer types such as breast (∼30% of tumors), esophageal (∼17% of tumors), lung (∼3%), ovarian (∼2%–66%), colorectal cancer (∼3%). Amplification is also seen in prostate cancer, salivary gland tumors, and bladder cancers.
    • ERBB2 gene mutations are drivers of several cancer types. In NSCLC, ERBB2 exon 20 in-frame insertion/duplication A775_G776insYVMA is the most prevalent.
    • Missense activating mutations in tyrosine kinase domains are seen in breast, lung, and lorectal cancers predominantly.
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