Leukemia cells do not differentiate into osteoclasts and do not resorb bone. Representative light micrographs of (A) normal and (B) leukemic spleen cells under osteoclastogenic conditions in vitro. Pink cells are positive for TRAP activity. (C) Quantification of TRAP⁺ cells in panels A and B. (D) Low and high power scanning electron micrographs of osteoclasts on bovine bone wafers. (E) Low and high power scanning electron micrographs of leukemia cells on bovine bone wafers. (F) ELISA quantification of CTX released into culture media during culture of cells with bovine bone wafers. (G-H) Representative light micrographs of cocultures containing osteoblasts and (G) normal marrow cells and (H) leukemic marrow cells. (I) Quantification of TRAP⁺ cells formed per well from osteoblastic cocultures with normal and leukemic marrows. *P ≤ .05. ***P ≤ .001. n = 3 or 4 mice per treatment group.