Gaucher disease and myeloma.

Gaucher disease (GD), the commonest lysosomal storage disorder, is an autosomal recessive condition, caused by deficiency in lysosomal glucocerebrosidase. Skeletal disease, peripheral blood cytopenias and hepato-splenomegaly are common at presentation. Several reports describe an increased risk of cancer in GD; in particular multiple myeloma. Tumor Associated Macrophages (TAMs) may promote cancerous expansion in non-GD patients, but it is unknown whether such an occurrence is present in GD. GD is traditionally described as a disorder of macrophages, associated with numerical and functional lymphoid abnormalities which could contribute to a state of impaired 'tumor surveillance'. These abnormalities include disturbances in invariant NK-T cells that depend on sphingolipid metabolism to deliver a physiological response. Glucosylceramide deposition, chronic antigenic stimulation, increased free radical production, impaired antigen presentation, reduced intra-cellular ceramide levels and disturbed autophagy have all been postulated to facilitate the growth of malignant clones in the GD microenvironment. At present, it is unknown whether carrier status for a GBA1 mutation confers an increased risk of malignancy. A cancer diagnosis is not currently an indication for GD-specific therapy in the absence of other features of the disease This article reviews cancer epidemiology, potential biological mechanisms of carcinogenesis and highlights areas of future research regarding malignancy in GD.