ERBB2 and breast cancer: As summarized in Fig. 1, partial responses (PRs) were observed in 7 patients (16.3%), including 3 patients with cholangiocarcinoma (8, 10, and 12 mg doses), 2 patients with HR-positive/HER2-negative breast cancer (10 and 12 mg doses), 1 patient with TNBC (12 mg dose), and 1 patient with castration-resistant prostate cancer (CRPC; 12 mg dose).