CD44 and neuroblastoma: A previous paper demonstrated that HA induced the differentiation of CD44‐positive (CD44+) human neuroblastoma (HTLA230) cells.23 These results implied that CD44 + neuroblastoma cells are sensitive to HA‐induced differentiation, which explains why CD44‐ cells are detected preferentially in neuroblastoma patients.21, 22 To explore the mechanisms of HA‐induced neuroblastoma cell differentiation, mouse N2a cells were serum deprived (0.1%‐7.5%) for 24 hours to establish an in vitro differentiation model.