CRLF2 expression associated with poor outcome in Philadelphia-negative acute lymphoblastic leukemia

Background Adult Philadelphia (Ph)-negative B-acute lymphoblastic leukemia (Ph-ALL) patients often exhibit elevated levels of CRLF2 expression, which is associated with poor clinical outcome. Aim To identify CRLF2 rearrangement in Ph-negative ALL patients and assess its prognostic significance. Methods The fluorescence in situ hybridization (FISH) technique was used to correlate the clinical outcome of 84 patients with Ph-ALL with a CRLF2 rearrangement from the hematology unit. Results This study included 84 newly diagnosed ALL patients. Based on their CRLF2 rearrangement status, the patients were divided into two groups: (CRLF2+) positive patients, comprising 17.9% of the total (n = 15), and (CRLF2-) negative patients, accounting for 82.1% (n = 69). In CRLF2+ patients, the median initial total leucocytic count (TLC) was 14.9 x 103 (range 4.8-486.0) vs. 6.9 x 103 (range 0.1-586.0) in CRLF2- patients (P = 0.005). Based on a median follow-up period of 333 days (range 36-730), the CRLF2+ group had shorter overall survival compared to the CRLF2- group (250 vs 730 days, P < 0.001). After a median follow-up of 198 days, the CRLF2+ group had a significantly lower disease-free survival compared to the CRLF2- group (184 vs 525 days, P < 0.001). Conclusion CRLF2 expression was associated with poor clinical outcomes among ALL patients.