Loss of ABCC5 in breast cancer cells results in diminished osteoclast numbers within osteolytic lesions. (A) Quantification of TRAP-positive osteoclasts within osteolytic lesions formed by human-derived 1833-BM1 cells (scr shRNA, n = 7; ABCC5 shRNA, n = 7; *P = 0.03). Representative images are shown for each group. The scale bars represent 100 μm and apply to both images. (B) Quantification of TRAP-positive cells present within bone metastases formed in mice injected with 4T1-derived populations (scr shRNA, n = 8; abcc5 shRNA 1, n = 6; abcc5 shRNA 2, n = 5; **P < 0.001; ***P < 0.001). Representative images are shown for each group. The scale bar in the upper image represents 100 μm and applies to all images.