Analysis of Serum Sphingomyelin Species by Uflc-Ms/Ms in Patients Affected with Monoclonal Gammopathy

Cancer cells are hungry of cholesterol incorporated from serum with avidity and used to favour the expressions of proteins involved in cell proliferation such as RNA polymerase II, STAT3, PKCz and cyclin D1. Numerous studies have shown that exists a strong interaction between unesterified cholesterol and saturated fatty acid sphingomyelin which arises from the Van der Waals interaction. Since sphingomyelin and cholesterol association is responsible for the formation of membrane lipid raft involved in cell signalling, we studied the possible hyposphingomyelinemia associated to hypocholesterolemia in the patients with cancer. The blood of 23 patients with monoclonal gammopathy were analyzed for cholesterol, 12:0 sphingomyelin, 16:0 sphingomyelin and 18:1sphingomyelin content. The results demonstrated that only the patients with very low level of cholesterol (65-99 mg/dl) had low amount of sphingomyelin and, in particular, of saturated sphingomyelin specie (16:0 sphingomyelin). The possibility that the hypocholesterolemia in cancer was secondary to hyposphingomyelinemia was discussed.