Tumor DNA was sequenced using a customized QiaSeq panel (Qiagen, Hilden, Germany) of genes known to be relevant for pediatric solid tumors, including ALK, BRAF, BRCA1/2, EGFR, FGFR1, KIT, MAP2K1/2, NF1, PDGFRA/B, PIK3CA, PTEN, PTPN11, RAS family genes, etc. The assay allowed detection of nucleotide substitutions and small insertions/deletions, as well as gene copy number alterations. This evidence concerns the gene PTPN11 and neoplasm.