PTHLH and breast carcinoma: PTHrP displays complex and even paradoxical actions towards cancer depending on stage, tumor type, and microenvironment.(38) For example, PTHrP expression in breast cancer patients has been linked to improved outcomes in a prospective patient cohort,(39) and the ablation of PTHrP has been reported to increase tumor progression and inhibit animal survival in the MMTV‐neu mouse,(40) a late‐onset mammary cancer model.