Prognostic value of the International Scoring System and response in patients with advanced Waldenstrom macroglobulinemia.

showed at karyotypic examination a deletion that included the NPM1 gene locus at 5q35. However, it should be noted that the inaccuracy of the deleted region assignment by chromosome banding has been reported for 5q deletions in both MDS and AML. Our findings suggest that NPM1 haploinsufficiency may have a role in myeloid malignancies associated with large 5qdeletions contributing to MDS development likely through genetic instability. This would be in line with the finding that NPM1 is haploinsufficient in the control of centrosome duplication in the mouse model, as well as with evidence that NPM1 hypomorphic mouse embryonic fibroblasts reveal high levels of tetraploidy and aneuploidy. Alternatively, NPM1 deletions may represent secondary events linked to the progression of the disease in MDS. Given the low number of cases and heterogeneity of treatments, we were unable to determine here the clinical significance of NPM1 deletion in MDS with 5q-. Hence a larger series of cases including homogeneously treated patients is needed to investigate the prognostic impact of these abnormalities.