Vranic et al. [12] and Weigelt et al. [13] proposed that these cancers have heterogeneous gene-expression profiles with multiple molecular subtypes rather than constituting a distinct category; however, they noted that pure apocrine cancer, limited to a characteristic profile of ER negative and PR negative defines a group that is either HER-2 overexpressing or triple-negative with consequent therapeutic implications. Here, ESR1 is linked to cancer.