Analysis of the genes identified by DCglob that showed higher correlation in ER- compared to ER+ breast cancer. The gene clusters (C) were compared to lists of marker genes (M) from the literature. Let #C denote the number of genes in the clusters, #M the number of marker genes and #(C ∩M) the number of genes in the intersection. The significance of enrichment was assessed using Fisher’s exact test. IAC invasive apocrine carcinomas, AR androgen receptor.