Figure 1.

PTHrP has different actions throughout cancer progression. Early in tumorigenesis PTHrP is protective against tumor formation in the primary site by decreasing proliferation, promoting apoptosis, decreasing angiogenesis and reducing tumor cell invasion and migration. Late in disease progression when tumor cells disseminate to distant sites, PTHrP promotes tumor progression and exit from dormancy by stimulating proliferation and angiogenesis while reducing apoptosis and immunosurveillance. These actions in advanced stages of disease contribute to poor patient outcomes and reduced survival. PTHrP, parathyroid hormone-related protein.