Clusters 1 and 2 had high AR signaling/luminal pathway scores and low neuroendocrine scores but were distinguished by lower (cluster 1) versus higher (cluster 2) proliferation scores, analogous to the luminal-A and luminal-B transcriptional phenotypes first described in breast cancer (38, 39) and more recently in prostate cancer (11–13, 40, 41). The gene discussed is AR; the disease is breast cancer.