The Achilles study used a similar doxycycline dosing regimen to that previously reported in a Phase I study in 17 patients with newly diagnosed metastatic breast cancer to the bone, which observed trends for decreased bone turnover as measured by the markers N-telopeptide and bone-specific alkaline phosphatase (BSAP) following doxycycline administration [26]. Here, PAX5 is linked to breast cancer.