The gene list generated for the basal cytokeratin immunopositive tumors within the ER-negative tumor entity (Additional file 2) included genes associated with ER status such as TTF1 (rank 13) and XBP1 (rank 16) and other genes previously associated with the basal-like tumor subtype such as CRYAB (rank 26), TRIM29 (rank 51), ERBB2 (rank 55), ANXA8 (rank 134), and EGFR (rank 193) [6-9]. Here, TTF1 is linked to neoplasm.