Tumor Humors and the Hypercalcemias of Cancer

Abstract

Hypercalcemia occurs frequently in the presence of a wide variety of neoplasms. In a number of cases the elevated plasma calcium appears to have a humoral etiology. On occasion, it has been shown that the tumor inappropriately produces parathyroid hormone or a parathyroid hormone-like substance.¹ In other cases, however, it has not been possible to measure parathyroid hormone either in the patient's plasma or in tumor extracts despite the use of highly sensitive immunologic procedures.² In such cases, which are not uncommon, other causes for the hypercalcemia must be sought.As knowledge of the endocrine and pharmacologic regulation of calcium . . .