Nevertheless, using the Gene Expression Profiling Interactive Analysis (GEPIA) database (http://gepia.cancer-pku.cn/detail.php?gene=SFRP1) (http://gepia.cancer-pku.cn/detail.php?gene=SFRP2), which incorporates the TCGA data, we noticed that both the SFRP1 and SFRP2 transcripts significantly decrease in bladder urothelial carcinoma (n = 404) compared to their paired normal tissue (n = 28). Here, SFRP1 is linked to bladder transitional cell carcinoma.