Serum CD44 levels predict survival in patients with low-risk myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematopoietic stem cell disorders that are preferentially diagnosed in the elderly. Aberrant expression of the adhesion receptor CD44 correlates with poor prognosis in various neoplasms. To evaluate the prognostic impact of CD44 in MDS serum levels of soluble CD44 standard (solCD44s) were measured in 130 MDS patients (median age 68 years) using an enzyme-linked immunosorbent assay (ELISA). solCD44s levels were significantly elevated in MDS patients as compared to those of healthy donors (p<0.001) and were found to correlate with distinct FAB and WHO subtypes. The highest levels of solCD44s were found in patients with CMML, in RAEB and in patients with MDS transformed into secondary acute myeloid leukaemia (AML). In univariate analysis elevated levels of solCD44s (cut-off level>688.5ng/ml) correlated significantly with shorter overall survival in MDS patients (12 versus 39 months; p<0.001). In multivariate analysis solCD44s displayed prognostic significance independent of the International Prognosis Scoring System (IPSS). To test for refined prognostication, IPSS risk groups were split into two separate categories based on the solCD44s levels. Using this approach, MDS patients with a shorter survival were identified both in the IPSS low-risk (p=0.037) and in the IPSS intermediate-1-risk group (p=0.015). The CD44s-adjusted IPSS defines a cohort of MDS patients with unfavorable prognosis, which might be helpful in risk stratification and in therapeutic algorithms.