What is the relevance of Ikaros gene deletions as prognostic marker in pediatric Philadelphia negative B-cell precursor acute lymphoblastic leukemia?

We herewith focused the analysis of Ikaros gene deletions in a homogeneous cohort of 410 pediatric non-Down syndrome and Philadelphia chromosome-negative, B-cell precursor Acute Lymphoblastic Leukemia patients enrolled in Italy into the AIEOP-BFM ALL2000 study. We confirm their reported poor prognostic value, although the associated Event-free survival was relatively high (approximately 70%). The difference in the Cumulative incidence of relapse between patients positive or not for IKZF1 deletions was not marked (24.2% (5.9) vs 13.1% (1.8) overall and 23.9% (6.6) vs 16.5% (2.5) in the Intermediate risk subgroup). In line with this, IKZF1 deletions were not an independent prognostic factor of the hazard of relapse. Moreover, most IKZF1 deleted cases stratified in the high risk group relapsed, thus suggesting that their identification would then require an alternative treatment. In conclusion, the need and benefit of introducing IKZF1 deletions as an additional stratification marker for Ph negative BCP-ALL patients remains questionable.