Our current study showed that PCAT1 could be detected in exosomes derived from ESCC cells and was upregulated in serum of ESCC patients compared with healthy volunteer donors, which is consistent with the high levels of PCAT1 in the serum of multiple myeloma patients29 and the urine of bladder cancer patients19. The gene discussed is PCAT1; the disease is esophageal squamous cell carcinoma.