Genomic complexity and IGHV mutational status are key predictors of outcome of chronic lymphocytic leukemia patients with TP53 disruption.

Abstract

The clinical course of chronic lymphocytic leukemia (CLL) is extremely heterogeneous and while some patients achieve a normal lifespan, others succumb to the disease shortly after diagnosis. Recurrent chromosomal aberrations as detected by chromosome banding analysis (CBA) or fluorescent in situ hybridization (FISH) have a reproducible prognostic power in terms of response to therapy and survival.1–3 In particular, patients whose tumor cells harbor 17p deletions (17p-) are considered to have a shorter survival and, hence, high-risk CLL. This poor prognosis is, however, not universally true for all patients with 17p- CLL. Indeed, we and others have observed that some clinical-biological features, such as presence of B symptoms, advanced clinical stage, size of the 17p- clone, β2-microglobulin (β2M) concentration and IGH mutational status have a significant impact on the outcome of this subgroup of patients.4,5 Novel molecular studies have helped in the understanding of 17p- CLL. On one hand, TP53 mutations are present in more than 80% of cases with 17p deletion and in around 5% of patients without 17p deletion.6,7 On the other hand, next generation sequencing studies have revealed novel genetic aberrations such as NOTCH1 and SF3B1 mutations that have a negative impact on survival.8–10 Finally, genomic complexity, as defined by karyotyping1 or copy number (CN) arrays, has also been independently associated with disease transformation and poor outcome in patients with CLL.11,12 The aim of this study was to evaluate the prognostic value of concomitant molecular abnormalities in patients with CLL and TP53 aberrations as diagnosed by FISH, CBA or DNA sequencing.