In this cohort, no differences in CD38 status, IGHV gene mutation status, ZAP-70 expression or cytogenetic abnormalities as detected by FISH were observed between individuals with MBL and Rai stage 0 CLL with an ALC ≤10 x 109/L. The percentage of MBL patients free of treatment at 1, 2, and 5 years was 99%, 98%, and 93%, respectively.(19) Among MBL patients, B-cell count as a continuous variable (hazard ratio [HR]=2.9, P=0.04) was predictive of time to treatment (TTT)(19). Notably, no difference in survival was observed based on the percentage of B-cells that had CLL-like phenotype among those individuals whose total B-cell count was less than 1.5 x 109/L (P = 0.71) suggesting that having a high proportion of clonal B cells does not necessarily indicate an increased risk for progression among individuals with a total B-cell count <1.5 x 109/L. Among other demographic and prognostic parameters, CD38 status (HR=10.8; P=0.006) was associated with TTT, but age (P=0.62) and sex (P=0.99) were not(19). Because of an insufficient number of patients with ZAP-70, IGHV gene mutation status, or FISH analysis, the authors
