Background Results HER2 activation results in enhanced tumor growth in preclinical models Aberrant HER2 activation HER2 amplification or overexpressionHER2 (ERBB2) somatic mutations P P P P P P P P P Activation of downstream signal transduction pathways Subset of HER2 mutations result in constitutive kinase signaling, oncogenic transformation and enhanced tumor growth in preclinical models1 Biliary tract cancer and HER2 mutations Biliary tract cancer is a heterogeneous and rare disease with poor prognosis; ...