We also found higher proportions of patients with HER2+ and triple-negative subtypes in the included studies (HER2+ regardless of hormonal receptor status: 26 [402/1558]; and TN: 28 [374/1357]) compared to general breast cancer population referred to cancer statistics published by the US National Cancer Institute: the prevalence of the HER2+ and triple-negative subtypes was 14% and 10%, respectively [40]. This evidence concerns the gene ERBB2 and breast cancer.