Among patients with UBC, pancreatic cancer, or cholangiocarcinoma in the biomarker‐evaluable population, only 24.3% (9/37), 1.5% (1/66), and 8.2% (4/49), respectively, exhibited heterogeneous or homogeneous expression of HER2 (Table 4). Here, ERBB2 is linked to familial pancreatic carcinoma.