Since MYC is frequently amplified and overexpressed in breast cancers, we extracted the genes of the Core MYC signature from expression profiles of a set of 146 breast tissue samples that were previously hybridized to the same Agilent human oligonucleotide microarrays [37], and we determined if the Core MYC signature is found in any of the previously defined subtypes of breast tumors. This evidence concerns the gene MYC and breast cancer.