Next generation sequencing studies in Chronic lymphocytic leukemia (CLL) have revealed novel genetic variants that have been associated with disease characteristics and outcome. The aim of this study was to evaluate the prognostic value of recurrent molecular abnormalities in patients with CLL. Therefore, we assessed their incidences and associations with other clinical and genetic markers in the prospective multicenter COMPLEMENT1 trial (treatment naive patients not eligible for intensive treatment randomized to chlorambucil (CHL) vs. ofatumumab-CHL (O-CHL)). Baseline samples were available from 383 patients (85.6%) representative of the total trial cohort. Mutations were analyzed by amplicon-based targeted next generation sequencing (tNGS). In 52.2% of patients we found at least one mutation and the incidence was highest in NOTCH1 (17.0%), followed by SF3B1 (14.1%), ATM (11.7%), TP53 (10.2%), POT1 (7.0%), RPS15 (4.4%), FBXW7 (3.4%), MYD88 (2.6%) and BIRC3 (2.3%). While most mutations lacked prognostic significance, TP53 (HR2.02,p<0.01), SF3B1 (HR1.66,p=0.01) and NOTCH1 (HR1.39,p=0.03) were associated with inferior PFS in univariate analysis. Multivariate analysis confirmed the independent prognostic role of TP53 for PFS (HR1.71,p=0.04) and OS (HR2.78,p=0.02) and of SF3B1 for PFS only (HR1.52,p=0.02). Notably, NOTCH1 mutation status separates patients with a strong and a weak benefit from ofatumumab addition to CHL (NOTCH1wt:HR0.50,p<0.01, NOTCH1mut:HR0.81,p=0.45). In summary, TP53 and SF3B1 were confirmed as independent prognostic and NOTCH1 as a predictive factor for reduced ofatumumab efficacy in a randomized chemo (immune)therapy CLL trial. These results validate NGS-based mutation analysis in a multicenter trial and provide a basis for expanding molecular testing in the prognostic workup of patients with CLL. ClinicalTrials.gov registration number: NCT00748189.

• MeSH
• Leukemia, Lymphocytic, Chronic, B-Cell * diagnosis   drug therapy   genetics   MeSH
• Phosphoproteins genetics   MeSH
• Humans MeSH
• Mutation MeSH
• Prognosis MeSH
• Prospective Studies MeSH
• Receptor, Notch1 genetics   MeSH
• RNA Splicing Factors genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Clinical Trial, Phase III MeSH
• Multicenter Study MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Phosphoproteins MeSH
• Receptor, Notch1 MeSH
• RNA Splicing Factors MeSH

Chronic lymphocytic leukemia is associated with a highly heterogeneous disease course in terms of clinical outcomes and responses to chemoimmunotherapy. This heterogeneity is partly due to genetic aberrations identified in chronic lymphocytic leukemia cells such as mutations of TP53 and/or deletions in chromosome 17p [del(17p)], resulting in loss of one TP53 allele. These aberrations are associated with markedly decreased survival and predict impaired response to chemoimmunotherapy thus being among the strongest predictive markers guiding treatment decisions in chronic lymphocytic leukemia. Clinical trials demonstrate the importance of accurately testing for TP53 aberrations [both del(17p) and TP53 mutations] before each line of treatment to allow for appropriate treatment decisions that can optimize patients' outcomes. The current report reviews the diagnostic methods to detect TP53 disruption better, the role of TP53 aberrations in treatment decisions and current therapies available for patients with chronic lymphocytic leukemia carrying these abnormalities. The standardization in sequencing technologies for accurate identification of TP53 mutations and the importance of continued evaluation of TP53 aberrations throughout initial and subsequent lines of therapy remain unmet clinical needs as new therapeutic alternatives become available.

• MeSH
• Chromosome Deletion * MeSH
• Leukemia, Lymphocytic, Chronic, B-Cell diagnosis   genetics   therapy   MeSH
• Humans MeSH
• Chromosomes, Human, Pair 17 genetics   MeSH
• Mutation * MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Disease-Free Survival MeSH
• Prognosis MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Tumor Suppressor Protein p53 MeSH

We report on markedly different frequencies of genetic lesions within subsets of chronic lymphocytic leukemia patients carrying mutated or unmutated stereotyped B-cell receptor immunoglobulins in the largest cohort (n=565) studied for this purpose. By combining data on recurrent gene mutations (BIRC3, MYD88, NOTCH1, SF3B1 and TP53) and cytogenetic aberrations, we reveal a subset-biased acquisition of gene mutations. More specifically, the frequency of NOTCH1 mutations was found to be enriched in subsets expressing unmutated immunoglobulin genes, i.e. #1, #6, #8 and #59 (22-34%), often in association with trisomy 12, and was significantly different (P<0.001) to the frequency observed in subset #2 (4%, aggressive disease, variable somatic hypermutation status) and subset #4 (1%, indolent disease, mutated immunoglobulin genes). Interestingly, subsets harboring a high frequency of NOTCH1 mutations were found to carry few (if any) SF3B1 mutations. This starkly contrasts with subsets #2 and #3 where, despite their immunogenetic differences, SF3B1 mutations occurred in 45% and 46% of cases, respectively. In addition, mutations within TP53, whilst enriched in subset #1 (16%), were rare in subsets #2 and #8 (both 2%), despite all being clinically aggressive. All subsets were negative for MYD88 mutations, whereas BIRC3 mutations were infrequent. Collectively, this striking bias and skewed distribution of mutations and cytogenetic aberrations within specific chronic lymphocytic leukemia subsets implies that the mechanisms underlying clinical aggressiveness are not uniform, but rather support the existence of distinct genetic pathways of clonal evolution governed by a particular stereotyped B-cell receptor selecting a certain molecular lesion(s).

• MeSH
• Leukemia, Lymphocytic, Chronic, B-Cell genetics   metabolism   mortality   MeSH
• Cytogenetic Analysis MeSH
• Gene Frequency MeSH
• Gene Rearrangement, B-Lymphocyte MeSH
• Genes, Immunoglobulin MeSH
• Complementarity Determining Regions genetics   MeSH
• Immunoglobulin Joining Region genetics   MeSH
• Polymorphism, Single Nucleotide MeSH
• Humans MeSH
• Mutation * MeSH
• Biomarkers, Tumor * MeSH
• Prognosis MeSH
• Receptors, Antigen, B-Cell genetics   metabolism   MeSH
• Immunoglobulin Heavy Chains genetics   MeSH
• Immunoglobulin Variable Region genetics   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Complementarity Determining Regions MeSH
• Immunoglobulin Joining Region MeSH
• Biomarkers, Tumor * MeSH
• Receptors, Antigen, B-Cell MeSH
• Immunoglobulin Heavy Chains MeSH
• Immunoglobulin Variable Region MeSH