CD49d Is the Strongest Flow Cytometry–Based Predictor of Overall Survival in Chronic Lymphocytic Leukemia

Purpose Although CD49dis an unfavorable prognostic marker in chronic lymphocytic leukemia(CLL), definitive validation evidence is lacking. A worldwide multicenter analysis was performed using published and unpublished CLL series to evaluate the impact of CD49das an overall (OS) and treatment-free survival (TFS) predictor. Patients and Methods A training/validation strategy was chosen to find the optimal CD49dcutoff. The hazard ratio (HR) for death and treatment imposed by CD49dwas estimated by pooled analysis of 2,972 CLLs; Cox analysis stratified by center and stage was used to adjust for confounding variables. The importance of CD49dover other flow cytometry–based prognosticators (eg, CD38, ZAP-70) was rankedby recursive partitioning. Results Patients with ≥ 30% of neoplastic cells expressing CD49dwere considered CD49d+. Decrease in OS at 5 and 10 years among CD49d+ patients was 7% and 23% (decrease in TFS, 26% and 25%, respectively). Pooled HR of CD49dfor OS was 2.5 (2.3 for TFS) in univariate...