CCNB1IP1 and neuroblastoma: Moreover, enrichment of MYCN to the E‐box containing region of CCNB1IP1 promoter was detected in the co‐precipitated product of MYCN primary antibody by CHIP assay in MYCN‐AM NB cells or MYCN‐NA cells with MYCN exogenously introduced with MYCN (Figure 3L,M).