Relevant studies have shown [14] that the vast majority of male breast cancer patients are of HR-positive/HER2-negative subtype (84.1%), followed by HR-positive/HER2-positive subtype (12.7%), while triple-negative breast cancers are uncommon (2.3%), and HR-negative/HER2-positive subtype is rarer (0.8%). This evidence concerns the gene ERBB2 and breast cancer.