Inclusion Criteria:  Age at diagnosis at 1 to 365 days of life. The start of induction therapy within a time interval of study recruitment phase. The diagnosis of ALL is to be proved by the morphological, cytochemical, and immunological analysis of tumor cells in bone marrow (see "Diagnostics"). Patients with B-cell (Burkitt) ALL are excluded. Informed consent of the patient parents (guardians) to be treated in one of the clinics included in this study.  Exclusion Criteria:  The disease is a relapse of previously misdiagnosed and, therefore, inadequately treated ALL; There is severe concomitant disease, which significantly impedes chemotherapy protocol (such as multiple malformations, heart diseases, metabolic disorders, etc.); There is a lack of important data needed for the exact adherence to the cytostatic therapy according to a specific chemotherapy protocol (differential diagnosis of ALL-AML (acute myeloid leukemia) is not possible, stratification according to therapeutic group is not possible); The patient was treated before for a long time with cytotoxic drugs; There were treatment deviations not covered by the protocol and/or not due to side effects of treatment and/or complications of the disease