We performed a co-expression analyses of SFRP1 and ERG in 494 prostate adenocarcinomas samples from the TCGA database [31]; as expected, low positive correlation between SFRP1 and ERG expression was confirmed (Spearman (0, 26) and Pearson (0, 24) (Fig. 1c). The gene discussed is SFRP1; the disease is prostate adenocarcinoma.