MYCN and neoplasm: Meanwhile, enhanced cell proliferation was specifically observed in MYCN‐AM NB cells upon CCNB1IP1 exogenous expression, as manifested by an increase in the number of colony foci, accelerated cell growth, and an elevated proportion of EdU‐labeled cells and enlargement of tumour spheres, whereas its effect on NA NB cells was inconsistent (Figure 4E–H and Figure S5).