(18) And, according to the statistics published by the National Cancer Institute, between 2016 and 2020, HR-positive/HER2-negative was the most prevalent breast cancer subtype diagnosed among US women, followed by HR-negative/HER2-negative, HR-positive/HER2-positive, and HR-negative/HER2-positive subtypes in descending order of prevalence. This evidence concerns the gene ERBB2 and breast cancer.