Multivariate analysis identified a significantly shorter TFS in patients who were ZAP-70 + (P < 0.001), with increased GFR-B2M (P < 0.001), and del(11q) or del(17p) as detected by fluorescence in situ hybridization (FISH.     ///    "When OS was evaluated by multivariate analysis, age 65 years or older (P < 0.001) and poor risk FISH abnormalities (P < 0.001) had a confirmed adverse prognostic impact, but the predictive value of GFR-B2M was lost in the validation analysis. "    ///    "In conclusion, GFR-B2M is a better predictor of TFS than unadjusted B2M in CLL patients.. "    ///    "In all survival models, B2M did not attain independent significance unless GFR-B2M was eliminated from the analysis. "