Therefore, our aim was to analyze the changes in RANKL, OPG, and 25(OH)D levels; the RANKL/OPG ratio; and other bone turnover markers (BTM) [osteocalcin, tartrate-resistant acid phosphatase type 5b (TRACP-5b), and bone alkaline phosphatase (BAP)] from diagnosis to complete remission in children with ALL. Here, ACP5 is linked to acute lymphoblastic leukemia.