Spearman’s rank order correlation coefficients of relative gene expression values for SOX2, AXIN2, and DKK1 in breast cancer samples from The Cancer Genome Atlas (TCGA_BRCA_exp_HiSeqV2-2015-02-24) data set (n = 1,009), *p < 0.05. The gene discussed is DKK1; the disease is breast cancer.