In addition, endothelial cells were mainly found in normal and high-grade bladder urothelial carcinoma rather than low-grade (refer to Figure 1b in the publication of Chen et al., 2020), suggesting that high-grade tumors contain a high proportion of endothelial cells, which may be related to the high expression of endothelial and S1PR1 due to tumor invasion of normal tissues. The gene discussed is S1PR1; the disease is bladder transitional cell carcinoma.