Polymorphonuclear (PMN-) and monocytic (M-) MDSCs are elevated in bone metastases and produce inhibitory factors like ROS, NO and PD-L1 that suppress PD-1+ T cells. Non-activated T cells infiltrating bone metastases express RANKL and TNFα increasing osteoclastogenesis and osteolytic metastases. Activated T cells produce IFNγ and IL-4, inhibiting osteoclastogenesis. Immunotherapy-activated T cells could fight cancer cells and inhibit bone resorption.

Half and 5 of 8 heterozygous SLC34A3 carriers had osteoporosis and a history of fractures, respectively. Individuals with detected nephrocalcinosis had significantly increased 1,25-OH₂-D₃ levels and urinary calcium excretion but normal phosphate reabsorption rates. Therefore, optimized treatment and monitoring regimens are required to prevent nephrocalcinosis and skeletal deterioration.