A higher percentage of cells with 13q deletion predicts worse outcome in Chinese patients with chronic lymphocytic leukemia carrying isolated 13q deletion

Previous studies showed that, in chronic lymphocytic leukemia (CLL) patients with isolated 13q deletion (13q-), those carrying higher percentage of leukemic cells with 13q- had more aggressive diseases. However, the prognostic value of the percentage of leukemic cells with 13q- in Chinese CLL patients with isolated 13q- remained to be determined. Using interphase fluorescence in situ hybridization (FISH), we identified 82 patients (25.4%) with isolated 13q deletion from a cohort of 323 untreated CLL patients. Among patients with isolated 13q deletion, cases of 13q- cells ≥ 80% (13q-H) had significantly shorter time to first treatment (TTT) than those of < 80% 13q- cells (13q-L) (median 11 vs. 92 months, p = 0.0016). A higher lymphocyte count (p = 0.0650) was associated with 13q-H, while other clinical, immunophenotypic, or molecular features did not differ between patients with 13q-H and 13q-L. Although 13q-H only showed marginal significance in multivariate analysis of TTT (hazards ratio 2.007; 95% confidence interval 0.975–4.129; p = 0.059), it helped refine the risk stratification based on Binet stage or immunoglobulin heavy chain variable gene (IGHV) status. In cases in Binet A or B stage, patients with 13q-H had a significantly shorter TTT (median TTT 18 months vs. undefined, p = 0.0101). And in IGHV mutated patients, 13q-H was also associated with reduced TTT (median TTT 13q-H. 18 months vs. 13q-L undefined, p = 0.0163). In conclusion, the prognosis of CLL patients with isolated 13q deletion was heterogeneous with 13q-H identifying patients with worse outcome.