PTH1R is expressed in many tissues that also express PTHrP, including breast cancer cells (20–22).The anabolic actions of PTH on PTH1R are mediated by the stimulatory G protein Gs, which activates adenylyl cyclase, leading to an increase in cAMP levels and the activation of the PKA pathway (23, 24). This evidence concerns the gene PTHLH and breast carcinoma.