[Hypercalcemia in blood diseases and cancers]

The clinical classification of malignant hypercalcaemias according to the presence or absence of bone lesions no longer corresponds to the physiopathology of these hypercalcaemias as it is known today. Both focal osteolysis and humoral hypercalcaemia involve a number of substances, such as prostaglandins, cytokines, growth factors, PTH-rp and calcitriol, the action of which is neither specific nor single. A knowledge of their role in the pathogenesis of hypercalcaemia should lead to the development of antagonists for therapeutic purpose and to a better understanding of their individual physiological effects, since some of these mediators are present in non-tumoral tissues. In humoral hypercalcaemia, PTH-rp seems to play a major role on kidneys and bones.