...we present a case report of a patient with GBC harboring ERBB2 activating mutation on both the primary site and metachronous liver metastasis...we performed genomic profiling from the liver tumor using the NGS panel, Oncomine® Target Test system (OTT, Thermo Fisher Scientific). This revealed ERBB2 Ser310Phe (c.929C>T; VAF, 26%)...we treated the patient with lapatinib with a combination of capecitabine....Within a week of treatment, she experienced major subjective clinical improvement, which included resolution of peripheral edema. After 2 cycles of treatment, contrasted CT imaging showed a decrease in the size of tumor emboli and hepatic lesion...