Nevertheless, with this study we expect to obtain valuable inputs leading to a better understanding and potential treatment optimization of ALL, including to characterize for the first time the circadian rhythm of children with AL using sequential sampling on a systemic, as well as cellular level. To reduce bias due to the known seasonal changes in the expression of circadian clock genes [8], we aim for a continuous recruitment of subjects over the entire study-period. Here, CLOCK is linked to acute lymphoblastic leukemia.