Note in particular that for this scenario it is necessary to model the osteoclast-stimulation rate  to be dependent on the bone density (see Text S1 for details), i.e. we replace the reaction term in the osteoclast equation of (6) byAs shown in Figure 6, the tumor-derived production of RANKL leads to a reversal of the RANKL gradient. This evidence concerns the gene TNFSF11 and neoplasm.