ANPEP and rhabdomyosarcoma: In the present study, we found that APN deficiency significantly suppresses the growth of rhabdomyosarcoma, which was related to increasing the relative abundance of Prevotella and Helicobacter, and correlated to decreasing the relative abundance of Bacteroides, suggesting that the inhibitory effect of APN deficiency on rhabdomyosarcoma is associated with the alteration of gut microbiota.