In concordance with the results by Sunami et al., we found the methylation levels of all these seven CpG sites to be significantly lower in the basal-like subtype (corresponding to their group of double-negative tumours) compared with the luminal or HER2-enriched subtypes (corresponding to their ER-positive or HER2-positive tumours; Table 2). Here, ESR1 is linked to neoplasm.