Analysis of relapse-free survival data (S3B Fig) confirmed the same tendency of all EM signatures to predict poor survival in basal and luminal B tumors, and thus all of the only 24 genes comprising EM signatures exceeded the prognostic value of PCNA metagene and mammaprint signatures (Fig 2) to predict poor outcome in both ER+ and ER- breast cancer patients. The gene discussed is ESR1; the disease is breast cancer.