MYCN and neuroblastoma: We first observed a lower level of expression of CCL2 in MYCN-high neuroblastoma tumors (Fig. 4A, P < 0.001; Supplementary Fig. S6A), likely reflecting the repression of CCL2 expression by the MYCN oncogene, but some MYNC low neuroblastoma had low levels of CCL2 transcription, and the reverse was also true.