ERBB2 and hyperinsulinemic hypoglycemia, familial, 4: Their clinicodemographic characteristics included female predominance (60.9%), poor differentiation (86.7%), high family history of cancer (14.2%), low HER2 expression (12.2%), PD-L1 expression (43.0%) and mismatch repair (MMR) deficiency (1.0%), and a high proportion of peritoneal metastasis (49.3%).