In the case of breast cancer, it has been reported that types positive for estrogen receptors present high levels of oxidative stress added to the fact that those triple negative breast cancer would present lower levels of 8-hydroxy-2′deoxyguanosine, thus supporting the role that estrogen receptors such as HER2 could have in the induction of oxidative stress in breast cancer and even indicating a possible differentiation between the various breast cancer subtypes and the role of oxidative stress in each of them [73,74,75,76,77]. Here, ESR1 is linked to breast cancer.