Hepatic veno-occlusive diseases (VOD) during cancer treatment in children are serious toxicities that have occurred with interruptions of chemotherapy and risk of relapse. In addition, these toxicities have a negative impact on the patient's quality of life, serious long-term sequelae and are potentially fatal in children.

The risk factors associated with the occurrence of these complications are, to date, unknown, at the exception to the exposition to certain treatments (6-thioguanine, busulfan, actinomycin D, radiotherapy, etc.). To understand the effects of this toxicity and those of susceptibility to the disease becomes a major issue in the treatment of these children.

Case-control study, nested in two French multicenter cohorts, on pharmacognenetic, biological and clinical susceptibility factors associated with the occurrence of hepatic veno-occlusive disease during the anticancer treatment for nephroblastoma or acute lymphoblastic leukemia, with centralized genetic analysis.

After obtaining consent (patient or parents for minor patients), a blood sample is collected during the routine follow-up consultation and tubes are sent directly to Paris for the pharmacogenetic analysis at the end of the study.

Inclusion Criteria:

• Children aged < 18 years old at the time of cancer diagnosis
• Having been treated with a single line of treatment for nephroblastoma or ALL, in France between 2000 and 2018, and who did not receive allogeneic hematopoietic stem cell transplantation
• Weight greater than 5 kg at inclusion
• Informed consent dated and signed by the holder of the parental authority (if minor) or by the patient (if major) to take part in the study
• Affiliated to a Social Security scheme

Exclusion Criteria:

• Unavaibility of constitutional DNA
• Person who receive more than one treatment line for nephroblastoma or ALL in childhood or adolescence
• Pregnant, lactating or parturient women
• Person deprived of their liberty by judicial or administrative decision
• Person under psychiatric care under duress
• Person subject to legal protection
• Person unable to express their consent