Meanwhile, with cardiovascular death as the COD, the HER2+/HR− breast cancer subtype was dominant throughout the period and peaked at 1.02 ± 0.11%, followed by the TNBC subtype at 0.95 ± 0.07%, whereas the HER2+/HR+ subtype consistently remained the lowest, ranging from 0.29 ± 0.03% at month 24 to 0.59 ± 0.05% at month 48 (Figure 1b). This evidence concerns the gene ERBB2 and breast cancer.