Patients with DM and the control group had different molecular subtypes of BC (p = 0.01): the luminal A subtype was found in 80% and 71%, the luminal B in 11% and 11%, HER-2 in 1% and 8%, and the triple-negative/basal-like subtype in 7% and 10%, respectively. This evidence concerns the gene ERBB2 and diabetes mellitus.