Childhood B-acute Lymphoblastic Leukaemia and Role of CD9 Gene Regulation in Relapse

This study is investigating the role of a gene called CD9 in childhood B-cell acute lymphoblastic leukemia (B-ALL), a common childhood cancer of the blood. Researchers are collecting samples to understand how CD9 affects how the leukemia behaves and whether it could be targeted in future treatments. **You may be eligible if...** - Your child is under 18 years old - Your child has been diagnosed with B-ALL - The diagnosis was made at the participating center - You (as parent or guardian) have provided written informed consent **You may NOT be eligible if...** - The leukemia is only found in sites outside the bone marrow at the start of the study - The patient is of childbearing age without using effective contraception - The patient is subject to legal protection measures Talk to your doctor to see if this trial is right for you.