The role of NPM1 alternative splicing in patients with chronic lymphocytic leukemia.

OBJECTIVES: Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease with heterogeneous clinical course. Recent studies revealed a link between NOTCH1 mutation and the overexpression of MYC and MYC-related genes involved in ribosome biogenesis and protein biosynthesis, such as nucleophosmin-1 (NPM1), in CLL cells. In the present study, we aim to evaluate the impact of the NOTCH1 mutation on the MYC and MYC induced NPM1 expression in CLL cells via quantification of their transcripts. METHODS: Using qRT-PCR, we analyzed the levels of MYC and three main NPM1 splice variants in 214 samples collected from CLL patients. We assessed the impact of each splice variant on CLL prognostic markers, including the IGHV, TP53, NOTCH1, SF3B1, and MYD88 mutational status, cytogenetic aberrations, and laboratory features. RESULTS: Significantly higher levels of NPM1.R1 transcripts in patients with unmutated compared to mutated IGHV status were found. The median time to first treatment (TTFT) in patients with a high level of NPM1.R1 was significantly shorter compared to the group with low NPM1.R1 levels (1.5 vs 33 months, p = 0.0002). Moreover, in Multivariate Cox Proportional Hazard Regression Model NPM1.R1 splice variant provided an independent prognostic value for TTFT. CONCLUSION: In conclusion, our study indicates the prognostic significance of the level of NPM1.R1 expression and suggests the importance of splicing alterations in the pathogenesis of CLL.

The Predominant Prognostic Significance of NOTCH1 Mutation Defined by Emulsion PCR in Chronic Lymphocytic Leukemia.

PURPOSE: NOTCH1 mut represents a new prognostic marker in chronic lymphocytic leukaemia (CLL). The low sensitivity of the current methods may increase the risk of false-negative results, particularly in patients with low NOTCH1 mut allelic burden. This study compared two methods of the NOTCH1 mut assessment including droplet digital PCR (ddPCR) and amplification-refractory mutation system PCR (ARMS-PCR) untreated CLL patients. PATIENTS AND METHODS: This study included 319 untreated CLL patients. Two PCR-based methods; ddPCR and ARMS-PCR were performed to assess the mutational status of NOTCH1. The Mann-Whitney, Fisher's exact test, Kruskal-Wallis, Kaplan-Meier, Log rank tests and multivariate Cox proportional hazard regression model were used to analyze collected data. RESULTS: We proved that ddPCR increased the detectability of the NOTCH1 mut compared to ARMS-PCR in CLL (18.55% vs 6%). We showed a shorter time to first treatment (TTFT) in the NOTCH1 mut group of patients compared to the NOTCH1 wt defined by ddPCR (1.5 vs 33 months, p=0.01). The TTFT survival curves analysis in subgroups divided according to the mutational status of IGHV and NOTCH1 assessed by ddPCR discriminated group with the best prognosis: IGHV mut NOTCH1 wt. Multivariate analysis revealed that the mutational status of IGHV represented an independent prognostic factor for TTFT, while NOTCH1 mut determined by ddPCR constituted as a dependent prognostic factor for TTFT. CONCLUSION: The selection of the precise method of NOTCH1 mut detection as ddPCR might significantly improve prognostic stratification of CLL patient. Assessment of IGHV might be relevant to more accurate discrimination of prognostic groups of CLL patients, especially in harboring NOTCH1 mut irrespective of the quantity of allelic burden.

Mean Platelet Volume Has Prognostic Value in Chronic Lymphocytic Leukemia.

PURPOSE: Mean platelet volume (MPV) is a readily accessible and commonly tested hematological indicator. Recent studies revealed a significant impact of MPV on the course and prognosis of many diseases, including some types of cancer, as well as on the incidence of atrial fibrillation and bleeding. The study aimed to perform a retrospective analysis of MPV in terms of time to first treatment (TTFT) and to determine its prognostic value in the group of patients with chronic lymphocytic leukemia (CLL). Moreover, the study includes a retrospective analysis of platelet parameters in patients treated with ibrutinib concerning bleeding and atrial fibrillation. PATIENTS AND METHODS: The study included 523 patients with CLL, for 344 the most important cytogenetic aberrations were reported. The Mann-Whitney, Kruskal-Wallis, Kaplan-Meier, chi-squared, log­rank tests and multivariate Cox proportional hazard regression model were used to analyze collected data. RESULTS: The receiver operating characteristic curve analysis was performed to identify optimal cut-off value for MPV. The analysis of survival curves showed that in the group of patients with higher values of MPV TTFT was significantly longer than in the group with lower MPV (17.9 vs 36 months, p=0.0015, cut-off value for MPV= 10.4 fl). In multivariate Cox proportional hazard regression model low MPV, the presence of del11q and del13q provided independent prognostic value for TTFT (HR=0.69, 95%-CI, 0.5293 to 0.9081; p=0.0078; HR=1.76, 95%-CI, 1.3000 to 2.3882, p=0.0003, HR=0.74, 95%-Cl, 0.5674 to 0.9588, p=0.0229, respectively). In the group treated with ibrutinib, 59 patients had no significant correlation between MPV level and the incidence of therapy complications, although in the group of patients with low MPV there was a tendency for more frequent occurrence of atrial fibrillation (p=0.259). CONCLUSION: Low MPV values are associated with unfavorable prognosis and might represent a novel, independent prognostic factor in CLL.