PTH and postmenopausal osteoporosis: Indeed, the 2-year chronic administration of teriparatide, or rhPTH(1–34), a synthetic agonist of human PTH currently under investigation for the treatment of postmenopausal osteoporosis, was shown to potentially impact carcinogenicity by causing the formation of osteosarcomas in F344 rats, although the same finding has not been reported in the clinical setting thus far82,83.