Gene expression profiling identifies ARSD as a new marker of disease progression and the sphingolipid metabolism as a potential novel metabolism in chronic lymphocytic leukemia

Background: Several studies demonstrated IGVH mutational status and ZAP70 expression as the most relevant prognostic markers in Chronic Lymphocytic Leukemia (CLL), suggesting the separation of two patient subgroups: with good mutated ZAP70 negative (MTZAP70(-)) and poor unmutated ZAP70 positive (UMZAP70(+)) prognosis. Design and methods: We determined the gene expression of B cells in 112 CLL patients divided into three classes: class 1 with MTZAP70(-), class 2 with UMZAP70(+), and class 3 included both UMZAP70(-) and MTZAP70(+). Results: We found LPL, AGPAT2, MBOAT1, CHPT1, AGPAT4, PLD1 genes encoding enzymes involved in lipid metabolism overexpressed in UMZAP70(+). In addition, this study identified ARSD, a gene belonging to the sphingolipid metabolism, as a new gene significantly overexpressed in UMZAP70(+) compared to MTZAP70(-). Western blots confirmed that ARSD protein levels were significantly different between the 3 classes of patients and normal controls. Statistical analysis identified a significant correlation between ARSD and IGVH; however, both ARSD protein level and IGVH were independently associated with the need for therapy of CLL patients. Conclusions: ARSD is a novel prognostic factor as the time to start therapy is shorter in patients with high levels of ARSD protein and sphingolipid metabolism could represent a new biological mechanism in CLL.