ERBB2 and neoplasm: We found that both HER2+ and HR+/HER2- tumor subtypes had significant epigenetic age accelerations towards older ages (median EAAD = 8.9 and 8.8 years, p = 0.04 and 3.8 × 10−6, respectively), while TNBC showed no significant epigenetic age acceleration (median EAAD = − 1.3 years, p = 0.86) (Fig. 7a).