Patients
Fresh-frozen HBs (n=21) and matched non-tumoral liver tissues (n=9) were recovered from biobanks. All patients received pre-surgery chemotherapy according to either SIOPEL (http://www.siopel.org /) or COG (https://www.childrensoncologygroup.org /) protocols, and they were followed by clinical examination, imaging tests, and alpha-fetoprotein dosage. This study was approved by the Ethics Committees of the A.C. Camargo Cancer Center and GRAACC. Biological samples were collected after signed informed consent obtained from parents.