Molecular profiling refines MRD-based prognostic assessment in adults with Philadelphia chromosome-negative B-cell precursor acute lymphoblastic leukemia.

Minimal residual disease (MRD) assessment is an essential tool in contemporary acute lymphoblastic leukemia (ALL) protocols, being used for therapeutic decisions such as hematopoietic stem cell transplantation in high-risk patients. However, a significant proportion of adult ALL patients with negative MRD still relapse suggesting that other factors (ie, molecular alterations) must be considered in order to identify those patients with high risk of disease progression. We have identified partial IKZF1 gene deletions and CDKN2A/B deletions as markers of disease recurrence and poor survival in a series of uniformly treated adolescent and adult Philadelphia chromosome-negative B-cell progenitor ALL patients treated according to the Programa Espanol de Tratamientos en Hematologia protocols. Importantly, CDKN2A/B deletions showed independent significance of MRD at the end of induction, which points out the need for treatment intensification in these patients despite being MRD-negative after induction therapy.