CCND1 and neoplasm: Similarly to CCND1, expression of the cell cycle-related genes RB1 (retinoblastoma 1) and AR (androgen receptor) were also higher in luminal tumours relative to basal-like (Additional file 5: Figure S5, see “AR” and “RB1”, P <  0.001 for luminal A vs. basal-like comparisons).