MYCN and neoplasm: In the 11 cases with informative copy number profiles in both the primary tumor and CSF cfDNA samples, the comparison of CNA between the primary tumor and the cfDNA showed an excellent concordance (Figure 2), with amplifications of MYCN, a region on chromosome 20 and a region on chromosome 19 (n = 4), homozygous deletions or heterozygous copy number losses or gains, including the loss and gain of chromosome 17p.