The prevalence of HER2-zero, HER2-low and HER2 positive cases among all BC (0, 1+, 2+/ISH-, 2+/ISH+, and 3+) was 45.0% (95% CI 33.0–58.0%), 32.0% (95% CI 24.0–39.0%), and 23.0% (95% CI 16.0–29.0%), respectively (Fig 2). The gene discussed is ERBB2; the disease is breast cancer.