Spectrum of ASXL1 mutations in primary myelofibrosis: prognostic impact of the ASXL1 p.G646Wfs*12 mutation

Comprehensive genomic profiling reveals molecular subsets of ASXL1-mutated myeloid neoplasms

A large-scale genomic analysis of patients with ASXL1-mutated myeloid disease has not been performed to date. We reviewed comprehensive genomic profiling results from 6043 adults to characterize clinicopathologic features and co-mutation patterns by ASXL1 mutation status. ASXL1 mutations occurred in 1414 patients (23%). Mutation co-occurrence testing revealed strong co-occurrence (p < 0.01) between mutations in ASXL1 and nine genes (SRSF2, U2AF1, RUNX1, SETBP1, EZH2, STAG2, CUX1, CSF3R, CBL). Further analysis of patients with these co-mutations yielded several novel findings. Co-mutation patterns supported that ASXL1/SF3B1 co-mutation may be biologically distinct from ASXL1/non-SF3B1 spliceosome co-mutation. In AML, ASXL1/SRSF2 co-mutated patients frequently harbored STAG2 mutations (42%), which were dependent on the presence of both ASXL1 and SRSF2 mutation (p < 0.05). STAG2 and SETBP1 mutations were also exclusive in ASXL1/SRSF2 co-mutated patients and associated with divergent chronic myeloid phenotypes. Our findings support that certain multi-mutant genotypes may be biologically relevant in ASXL1-mutated myeloid disease.

Prognosis and risk factors for ASXL1 mutations in patients with newly diagnosed acute myeloid leukemia and myelodysplastic syndrome

OBJECTIVE

The objective of the study was to determine the prognosis and risk factors for additional sex combs like 1 (ASXL1) mutations in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

POPULATION AND METHODS

This retrospective study enrolled 219 adult patients with newly diagnosed AML and MDS, who were treated in West China Hospital from October 2018 to January 2022. The primary clinical outcome was evaluated by overall survival (OS) followed up to January 2023. Kaplan-Meier analysis and Cox multivariate regression analysis were performed to identify potential prognostic parameters in patients with ASXL1 mutations (mt).

RESULTS

A total of 34 (15.53%) ASXL1mt were detected, which occurred more frequently in the elderly and MDS cohorts (p < 0.001). Significantly lower blasts% (p < 0.001) and higher frequencies of mutant RUNX1, SRSF2, STAG2, EZH2, and SETBP1 (p < 0.02) were observed in the ASXL1mt cohort. Patients with ASXL1mt manifested with a worse complete remission rate (p = 0.011), and an inferior OS was shown in subgroups with MDS, co-mutations of RUNX1, SRSF2, or NRAS, as well as mutations in G646W (p < 0.05). Multivariate analysis considering age, diagnosis, co-mutations, and mutation site confirmed an independently adverse prognosis of mutations in G646W (HR = 4.302, 95% CI: 1.150-16.097) or RUNX1 co-mutations (HR = 4.620, 95% CI: 1.385-15.414) in the ASXL1mt cohort.

CONCLUSION

Our study indicated that mutations in G646W or RUNX1 co-mutations are closely associated with a dismal clinical outcome in patients with AML and MDS harboring ASXL1mt. Considering the poor prognosis and risk factors in patients with ASXL1mt, more available treatments should be pursued.

Biological drivers of clinical phenotype in myelofibrosis

Myelofibrosis (MF) is a myeloproliferative disorder that exhibits considerable biological and clinical heterogeneity. At the two ends of the disease spectrum are the myelodepletive or cytopenic phenotype and the myeloproliferative phenotype. The cytopenic phenotype has a high prevalence in primary MF (PMF) and is characterized by low blood counts. The myeloproliferative phenotype is typically associated with secondary MF (SMF), mild anemia, minimal need for transfusion support, and normal to mild thrombocytopenia. Differences in somatic driver mutations and allelic burden, as well as the acquisition of non-driver mutations further influences these phenotypic differences, prognosis, and response to therapies such as JAK2 inhibitors. The outcome of patients with the cytopenic phenotype are comparatively worse and frequently pose a challenge to treat given the inherent exacerbation of cytopenias. Recent data indicate that an innate immune deregulated state that hinges on the myddosome-IRAK-NFκB axis favors the cytopenic myelofibrosis phenotype and offers opportunity for novel treatment approaches. We will review the biological and clinical features of the MF disease spectrum and associated treatment considerations.

PCR-Fluo-ASXL1-FA: A fast, sensitive and inexpensive complementary method to detect ASXL1 mutations in haematological malignancies

INTRODUCTION

The additional sex combs like 1 (ASXL1) gene is frequently mutated in a number of haematological neoplasms. The c.1934dupG, known to be the most common alteration in ASXL1, is associated with poor clinical outcome. A systematic determination of ASXL1 mutational status in myeloid malignancies is therefore necessary for prognostic stratification.

METHODS

Because direct sequencing is not sensitive and next-generation sequencing (NGS) is time-consuming, expensive and sometimes does not allow the detection of the c.1934dupG, we have developed a fragment analysis assay, complementary to NGS, that allows the detection of c.1934dupG mutation in addition to other nearby insertions/deletions of ASXL1 located close to it. We called this assay the "PCR-Fluo-ASXL1-FA."

RESULTS

First, we evaluated the efficiency of our approach compared to NGS and Sanger. We showed that "PCR-Fluo-ASXL1-FA" could detect all insertional mutations of ASXL1 located on its area, with a high sensitivity (1.5%). Then, we have illustrated the interest of this technique by three concrete cases.

DISCUSSION

In summary, we have established a fragment analysis approach, which can detect most ASXL1 mutations, in particular the c.1934dupG, in a sensitive, fast and inexpensive manner. We therefore recommend the synchronous use of this method with NGS, to ensure complete detection of all clinically relevant ASXL1 mutations in patients suffering with myeloid neoplasms.

[Analysis of the effect of gene mutations on the efficacy of ruxolitinib in patients with myelofibrosis based on second-generation sequencing technology]

Objective: To assess the effect of gene mutations on the efficacy of ruxolitinib for treating myelofibrosis (MF) . Methods: We retrospectively analyzed the clinical data of 56 patients with MF treated with ruxolitinib from July 2017 to December 2020 and applied second-generation sequencing (NGS) technology to detect 127 hematologic tumor-related gene mutations. Additionally, we analyzed the relationship between mutated genes and the efficacy of ruxolitinib. Results: ①Among the 56 patients, there were 36 cases of primary bone marrow fibrosis (PMF) , 9 cases of bone marrow fibrosis (ppv-mf) after polycythemia vera, and 11 cases of bone marrow fibrosis (PET-MF) after primary thrombocytosis (ET) . ②Fifty-six patients with MF taking ruxolitinib underwent NGS, among whom, 50 (89.29%) carried driver mutations, 22 (39.29%) carried ≥3 mutations, and 29 (51.79%) carried high-risk mutations (HMR) . ③ For patients with MF carrying ≥ 3 mutations, ruxolitinib still had a better effect of improving somatic symptoms and shrinking the spleen (P=0.001, P<0.001) , but TTF and PFS were significantly shorter in patients carrying ≥ 3 mutations (P=0.007, P=0.042) . ④For patients carrying ≥ 2 HMR mutations, ruxolitinib was less effective in shrinking the spleen than in those who did not carry HMR (t= 10.471, P=0.034) , and the TTF and PFS were significantly shorter in patients carrying ≥2 HMR mutations (P<0.001, P=0.001) . ⑤Ruxolitinib had poorer effects on spleen reduction, symptom improvement, and stabilization of myelofibrosis in patients carrying additional mutations in ASXL1, EZH2, and SRSF2. Moreover, patients carrying ASXL1 and EZH2 mutations had significantly shorter TTF [ASXL1: 360 (55-1270) d vs 440 (55-1268) d, z=-3.115, P=0.002; EZH2: 327 (55-975) d vs 404 (50-1270) d, z=-3.219, P=0.001], and significantly shorter PFS compared to non-carriers [ASXL1: 457 (50-1331) d vs 574 (55-1437) d, z=-3.219, P=0.001) ; 428 (55-1331) d vs 505 (55-1437) d, z=-2.576, P=0.008]. Conclusion: The type and number of mutations carried by patients with myelofibrosis and HMR impact the efficacy of ruxolitinib.

Genomic analysis of primary and secondary myelofibrosis redefines the prognostic impact of ASXL1 mutations: a FIM study

We aimed to study the prognostic impact of the mutational landscape in primary and secondary myelofibrosis. The study included 479 patients with myelofibrosis recruited from 24 French Intergroup of Myeloproliferative Neoplasms (FIM) centers. The molecular landscape was studied by high-throughput sequencing of 77 genes. A Bayesian network allowed the identification of genomic groups whose prognostic impact was studied in a multistate model considering transitions from the 3 conditions: myelofibrosis, acute leukemia, and death. Results were validated using an independent, previously published cohort (n = 276). Four genomic groups were identified: patients with TP53 mutation; patients with ≥1 mutation in EZH2, CBL, U2AF1, SRSF2, IDH1, IDH2, NRAS, or KRAS (high-risk group); patients with ASXL1-only mutation (ie, no associated mutation in TP53 or high-risk genes); and other patients. A multistate model found that both TP53 and high-risk groups were associated with leukemic transformation (hazard ratios [HRs] [95% confidence interval], 8.68 [3.32-22.73] and 3.24 [1.58-6.64], respectively) and death from myelofibrosis (HRs, 3.03 [1.66-5.56] and 1.77 [1.18-2.67], respectively). ASXL1-only mutations had no prognostic value that was confirmed in the validation cohort. However, ASXL1 mutations conferred a worse prognosis when associated with a mutation in TP53 or high-risk genes. This study provides a new definition of adverse mutations in myelofibrosis with the addition of TP53, CBL, NRAS, KRAS, and U2AF1 to previously described genes. Furthermore, our results argue that ASXL1 mutations alone cannot be considered detrimental.

Prognostic value of ASXL1 mutations in patients with primary myelofibrosis and its relationship with clinical features: a meta-analysis

Additional sex combs like 1 (ASXL1) mutations are one of the most common molecular biological abnormalities in patients with primary myelofibrosis (PMF), and the effect of these mutations on prognosis remains controversial. Hence, we conducted a meta-analysis to assess the prognostic value and clinical characteristics of ASXL1 mutations in PMF patients. Eligible studies were systematically searched from PubMed, Embase, and the Cochrane Library. We extracted the hazard ratios (HRs) and their 95% confidence intervals (CIs) of overall survival (OS) and leukemia-free survival (LFS), the number of patients transformed to acute leukemia, and clinical characteristics to carry out a meta-analysis by fixed effect model or random effect model according to the heterogeneity between studies. A total of 4501 PMF patients from 16 cohorts of 14 studies were included in this meta-analysis. The results revealed that ASXL1 mutations might predict a shorter OS (HR = 2.30, 95% CI: 1.79-2.94, P < 0.00001) and a higher probability of transformation to acute leukemia (LFS: HR = 1.77, 95% CI: 1.30-2.42, P = 0.0003; the rate of acute leukemia transformation: OR = 2.06, 95% CI: 1.50-2.83, P < 0.00001). Furthermore, ASXL1 mutations were correlated with patients older than 65 years old, male, a lower level of platelet counts, and a higher risk of the international prognostic score system. These findings indicate that ASXL1 mutations have a significant adverse impact on the prognosis of PMF patients and may contribute to risk stratification and prognostic assessment for PMF patients.

[Analysis of gene mutations and clinic features in 108 patients with myeloproliferative neoplasm]

Objective: To analyze the genetic mutations and clinical features of the subtypes of classical BCR-ABL-negative myeloproliferative neoplasm (MPN) . Methods: Mutations of 108 newly diagnosed BCR-ABL-negative MPN patients [including 55 patients with essential thrombocytopenia (ET) , 24 with polycythemia vera (PV) , and 29 with primary myelofibrosis (PMF) ] were identified using next-generation sequencing with 127-gene panel, and the relationship between gene mutations and clinical features were analyzed. Results: Total 211 mutations in 32 genes were detected in 100 MPN patients (92.59% ) , per capita carried (1.96±1.32) mutations. 85.19% (92/108) patients carried the driver gene (JAK2, CALR, MPL) mutations, 69.56% (64/92) of these patients carried at least 1 additional gene mutation. In descending order of mutation frequency, the highest frequency was for activation signaling pathway genes (42.2% , 89/211) , methylation genes (17.6% , 36/211) , and chromatin-modified genes (16.1% , 34/211) . There was a significant difference in the number of mutations in the activation signaling pathway genes, epigenetic regulatory genes, spliceosomes, and RNA metabolism genes among the three MPN subgroups. The average number of additional mutations in PMF patients was higher than that in ET and PV patients (1.69±1.39, 0.67±0.70, 0.87±1.22, χ(2)=13.445, P=0.001) . MPN-SAF-TSS (MPN 10 score) (P=0.006) and myelofibrosis level (P=0.015) in patients with ≥ 3 mutant genes were higher and the HGB level (P=0.002) was lower than in those with<3 mutations. Twenty-six patients (24.1% ) carried high-risk mutation (HMR) , and patients with HMR had lower PLT (P=0.017) , HGB levels (P<0.001) , and higher myelofibrosis level (P=0.010) and MPN10 score (P<0.001) . The frequency of ASXL1 mutations was higher in PMF than in PV patients (34.5% vs. 4.2% , P=0.005) . PMF patients with ASXL1 had lower levels of PLT and HGB (P=0.029 and 0.019) . Conclusion: 69.56% of MPN patients carry at least one additional mutation, and 24.1% patients had HMR. Each subgroup had different mutation patterns. PMF patients had a higher average number of additional gene mutations, especially a higher frequency of ASXL1 mutation; PLT and HGB levels were lower in ASXL1 mutation PMF patients.