PTHLH and breast carcinoma: Interestingly, one of the original tumors from which PTHrP was purified and sequenced, because of the elevated concentration of its circulating form, was breast cancer [8,9] and it is now well-known that PTHrP exerts multiple effects on different neoplastic cytotypes via cytosolic and nuclear targets, thereby participating to initiate and promote tumor growth and dissemination [10].