Mutations of TP53 gene in adult acute lymphoblastic leukemia at diagnosis do not affect the achievement of hematologic response but correlate with early relapse and very poor survival

Prognostic impact of TP53 mutations in adult acute lymphoblastic leukemia treated with a pediatric-type regimen

The prognostic impact of TP53 mutations (TP53mut) in adult acute lymphoblastic leukemia (ALL) remains debatable. Herein, we determined the clinical significance of TP53mut in 283 adult ALL patients treated with a pediatric-type regimen. TP53mut were found in 11.0% (31) of patients, including 19 cases in adolescent and young adult (AYA) patients and 12 cases in non-AYA patients. Patients with TP53mut had poorer overall survival (OS) and event-free survival (EFS) in the non-AYA subgroup (n = 64) (3-year OS, 18.2% vs 50.9%, p = .0033; 3-year EFS, 0 vs 45.3%, p = .00028). however, this had to be taken cautiously due to a limited number of patients. In the AYA subgroup (n = 219), TP53mut did not impact OS or EFS (3-year OS, 60.6%vs71.0%, p = .55; 3-year EFS, 52.5%vs59.6%, p = .57). Collectively, our data reveal that the pediatric-type regimen eliminated the poor prognostic impact of TP53mut in AYA ALL. However, in non-AYA ALL patients, TP53mut remain a potential biomarker associated with poor outcomes.

Constitutively active CaMKII Drives B lineage acute lymphoblastic leukemia/lymphoma in tp53 mutant zebrafish

Acute lymphoblastic leukemia/lymphoma (ALL) is the most common pediatric cancer and is a malignancy of T or B lineage lymphoblasts. Dysregulation of intracellular Ca2+ levels has been observed in patients with ALL, leading to improper activation of downstream signaling. Here we describe a new zebrafish model of B ALL, generated by expressing human constitutively active CaMKII (CA-CaMKII) in tp53 mutant lymphocytes. In this model, B cell hyperplasia in the kidney marrow and spleen progresses to overt leukemia/lymphoma, with only 29% of zebrafish surviving the first year of life. Leukemic fish have reduced productive genomic VDJ recombination in addition to reduced expression and improper splicing of ikaros1, a gene often deleted or mutated in patients with B ALL. Inhibiting CaMKII in human pre-B ALL cells induced cell death, further supporting a role for CaMKII in leukemogenesis. This research provides novel insight into the role of Ca2+-directed signaling in lymphoid malignancy and will be useful in understanding disease development and progression.

Targeting WEE1 kinase as a p53-independent therapeutic strategy in high-risk and relapsed acute lymphoblastic leukemia

BACKGROUND

Outcomes for patients with relapsed acute lymphoblastic leukemia (ALL) are poor and there is a need for novel therapies to improve outcomes. Targeted inhibition of WEE1 with small-molecule inhibitor adavosertib (AZD1775) has emerged as a therapeutic strategy to sensitize cancer cells to DNA-damaging chemotherapeutics, particularly in the context of TP53-mutated tumors. However, WEE1 inhibition as a potential therapeutic strategy for patients with high-risk and relapsed ALL, including those with TP53 mutations, has not been definitively evaluated.

METHODS

Anti-leukemic effects of adavosertib were investigated using a relapsed TP53 isogenic cell model system, primary patient, and patient-derived ALL samples (n = 27) in an ex vivo co-culture model system with bone marrow-derived mesenchymal stem cells. Combination effects with drugs currently used for relapsed ALL were quantified by Excess over Bliss analyses. Investigations for alterations of cell cycle and apoptosis as well as related proteins were examined by flow cytometry and Western blot, respectively.

RESULTS

Our study demonstrates the potent anti-leukemic activity of the clinically advanced WEE1 inhibitor adavosertib in a large majority (n = 18/27) of high-risk and relapsed ALL specimens at lower than clinically attainable concentrations, independent of TP53 mutation status. We show that treatment with adavosertib results in S-phase disruption even in the absence of DNA-damaging agents and that premature mitotic entry is not a prerequisite for its anti-leukemic effects. We further demonstrate that WEE1 inhibition additively and synergistically enhances the anti-leukemic effects of multiple conventional chemotherapeutics used in the relapsed ALL treatment setting. Particularly, we demonstrate the highly synergistic and cytotoxic combination of adavosertib with the nucleoside analog cytarabine and provide mechanistic insights into the combinational activity, showing preferential engagement of apoptotic cell death over cell cycle arrest. Our findings strongly support in vivo interrogation of adavosertib with cytarabine in xenograft models of relapsed and high-risk ALL.

CONCLUSIONS

Together, our data emphasize the functional importance of WEE1 in relapsed ALL cells and show WEE1 as a promising p53-independent therapeutic target for the improved treatment of high-risk and relapsed ALL.

The clinical characteristics and prognosis in adult Ph negative acute lymphoblastic leukemia with TP53 aberrations

Very few reports elucidate the prognosis of patients with TP53 aberrations using both measurable residual disease (MRD) and the status of having undergone allogeneic hematopoietic stem cell transplantation (allo-SCT). In this study, aberrations of TP53 were analyzed using next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH) in patients with Philadelphia chromosome-negative (Ph^-) ALL enrolled in a prospective single-arm clinical trial at our leukemia center. We analyzed the survival of the patients grouped according to the MRD level at the third month and whether or not received allo-SCT. We found that allo-SCT could improve the OS in patients with TP53 aberrations; Patients having negative MRD at the third month still showed worse 3-year OS and 3-year DFS without undergoing allo-SCT, which is different from previous studies, moreover, the prognostic significance of TP53 deletions was as important as TP53 mutations, the importance of screening both TP53 deletions and mutations in adult Ph^- ALL at diagnosis should be emphasized.

Repeated Lineage Switches in an Elderly Case of Refractory B-Cell Acute Lymphoblastic Leukemia With MLL Gene Amplification: A Case Report and Literature Review

Lineage switches in acute leukemia occur rarely, and the underlying mechanisms are poorly understood. Herein, we report the case of an elderly patient with leukemia in which the leukemia started as B-cell acute lymphoblastic leukemia (B-ALL) and later changed to B- and T-cell mixed phenotype acute leukemia (MPAL) and acute myeloid leukemia (AML) during consecutive induction chemotherapy treatments. A 65-year-old woman was initially diagnosed with Philadelphia chromosome-negative B-ALL primarily expressing TdT/CD34/HLA-DR; more than 20% of the blasts were positive for CD19/CD20/cytoplasmic CD79a/cytoplasmic CD22/CD13/CD71.The blasts were negative for T-lineage markers and myeloperoxidase (MPO). Induction chemotherapy with the standard regimen for B-ALL resulted in primary induction failure. After the second induction chemotherapy regimen, the blasts were found to be B/T bi-phenotypic with additional expression of cytoplasmic CD3. A single course of clofarabine (the fourth induction chemotherapy regimen) dramatically reduced lymphoid marker levels. However, the myeloid markers (e.g., MPO) eventually showed positivity and the leukemia completely changed its lineage to AML. Despite subsequent intensive chemotherapy regimens designed for AML, the patient’s leukemia was uncontrollable and a new monoblastic population emerged. The patient died approximately 8 months after the initial diagnosis without experiencing stable remission. Several cytogenetic and genetic features were commonly identified in the initial diagnostic B-ALL and in the following AML, suggesting that this case should be classified as lineage switching leukemia rather than multiple simultaneous cancers (i.e., de novo B-ALL and de novo AML, or primary B-ALL and therapy-related myeloid neoplasm). A complex karyotype was persistently observed with a hemi-allelic loss of chromosome 17 (the location of the TP53 tumor suppressor gene). As the leukemia progressed, the karyotype became more complex, with the additional abnormalities. Sequential target sequencing revealed an increased variant allele frequency of TP53 mutation. Fluorescent in situ hybridization (FISH) revealed an increased number of mixed-lineage leukemia (MLL) genes, both before and after lineage conversion. In contrast, FISH revealed negativity for MLL rearrangements, which are well-known abnormalities associated with lineage switching leukemia and MPAL. To our best knowledge, this is the first reported case of acute leukemia presenting with lineage ambiguity and MLL gene amplification.

Pre-HCT mosaicism increases relapse risk and lowers survival in acute lymphoblastic leukemia patients post-unrelated HCT

Pre-HCT mosaicism is related to increased relapse risk and lower survival after unrelated HCT, independent of cytogenetics at diagnosis. Pre-HCT mosaicism could be a useful clinical tool to guide risk stratification in acute lymphoblastic leukemia patients.

[Clinical and prognostic values of TP53 mutation in patients with B-lineage acute lymphoblastic leukemia]

Objective: To investigate the survival and prognosis of B-lineage acute lymphoblastic leukemia (B-ALL) patients with TP53 mutation. Methods: The clinical data of 479 newly diagnosed B-ALL patients treated in the First Affiliated Hospital of Soochow University from January 2016 to December 2019 were retrospectively analyzed. Results: Among 479 B-ALL patients, 34 cases (7.1%) were positive for TP53 gene mutation, and a total of 36 TP53 mutations were detected, including 10 frameshift gene mutations (27.8%) , 23 missense mutations (63.9%) and 3 nonsense mutations (8.3%) . A total of 34 (94.4%) mutations were located in the DNA binding domain (exons 5-8) .The average number of mutated genes in patients with TP53 gene mutation (2.3) and the group without TP53 gene mutation (1.1) were statistically different (P<0.001) . The proportion of Ph positive and Ph-like positive patients in the TP53 gene mutation negative group was significantly higher than that of the TP53 mutation positive group, and the difference was statistically significant (P<0.001) . The 3-year OS and EFS rates of the TP53 gene mutation negative group were significantly higher than those of the TP53 gene mutation positive group. The differences in OS and EFS rates between the two groups were statistically significant (χ(2)= 4.694, P = 0.030; χ(2)= 5.080, P= 0.024) . In the multivariate analysis, failure to achieve remission (CR) after one course of induction chemotherapy was an independent adverse prognostic factor affecting OS.Of the 34 patients with TP53 mutation, 16 underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the CR(1) state, and 2 patients with recurrence after transplantation obtained CR(2) after infusion of donor-derived anti-CD19 chimeric antigen receptor T (CAR-T) cells. Among the 11 patients with TP53 gene mutation who relapsed during consolidation chemotherapy, 6 received anti-CD19 CAR T cell therapy, 4 patients achieved remission and minimal residual disease (MRD) turned negative, followed by bridging allo-HSCT, and 2 of them sustained CR. Conclusion: Missense mutations are the most common in B-ALL patients with TP53 gene mutation, and the majority of mutations were located in the DNA binding domain. B-ALL patients with TP53 gene mutation should undergo allo-HSCT as soon as possible after CAR-T cell therapy has cleared the MRD after recurrence. B-ALL patients with TP53 gene mutation still have a higher recurrence rate after allo-HSCT, and the infusion of donor-derived CAR-T cells can achieve better sustained remission.

[The effect of TP53 mutations on the clinical outcomes of Ph-negative B-acute lymphoblastic leukemia following allogeneic hematopoietic stem cell transplantation]

目的

探讨TP53基因突变对Ph阴性急性B淋巴细胞白血病（B-ALL）异基因造血干细胞移植（allo-HSCT）疗效的影响。

方法

回顾性研究2012年5月至2017年5月在河北燕达陆道培医院行allo-HSCT的300例Ph阴性B-ALL患者的临床特点和TP53基因突变发生情况，分析TP53基因突变对移植后无白血病生存（LFS）、总生存（OS）、非复发相关死亡（NRM）、累积复发率（RI）和移植物抗宿主病（GVHD）发生的影响。

结果

共23例患者检出TP53基因突变，突变位点均位于DNA结合区。TP53基因突变组和非突变组5年LFS率分别为34.8%和62.3%（P=0.001），5年OS率分别为41.9%和65.1%（P=0.020），5年RI分别为47.8%和14.8%（P=0.000），而两组间在GVHD和NRM上差异无统计学意义（P>0.05）。多因素分析显示，TP53基因突变仍然是影响移植后OS、LFS和RI的不良因素。

结论

allo-HSCT可以使部分具有TP53基因突变的Ph阴性B-ALL患者获得长期生存。TP53基因突变是影响Ph阴性B-ALL患者allo-HSCT预后的独立危险因素。

Immature Immunoglobulin Gene Rearrangements Are Recurrent in B Precursor Adult Acute Lymphoblastic Leukemia Carrying TP53 Molecular Alterations

Here, we describe the immunoglobulin and T cell receptor (Ig/TCR) molecular rearrangements identified as a leukemic clone hallmark for minimal residual disease assessment in relation to TP53 mutational status in 171 Ph-negative Acute Lymphoblastic Leukemia (ALL) adult patients at diagnosis. The presence of a TP53 alterations, which represents a marker of poor prognosis, was strictly correlated with an immature DH/JH rearrangement of the immunoglobulin receptor (p < 0.0001). Furthermore, TP53-mutated patients were classified as pro-B ALL more frequently than their wild-type counterpart (46% vs. 25%, p = 0.05). Although the reasons for the co-presence of immature Ig rearrangements and TP53 mutation need to be clarified, this can suggest that the alteration in TP53 is acquired at an early stage of B-cell maturation or even at the level of pre-leukemic transformation.

Capture-based Next-Generation Sequencing Improves the Identification of Immunoglobulin/T-Cell Receptor Clonal Markers and Gene Mutations in Adult Acute Lymphoblastic Leukemia Patients Lacking Molecular Probes

The monitoring of minimal residual disease (MRD) in Philadelphia-negative acute lymphoblastic leukemia (ALL) requires the identification at diagnosis of immunoglobulin/T-cell receptor (Ig/TCR) rearrangements as clonality markers. Aiming to simplify and possibly improve the patients' initial screening, we designed a capture-based next-generation sequencing (NGS) panel combining the Ig/TCR rearrangement detection with the profiling of relevant leukemia-related genes. The validation of the assay on well-characterized samples allowed us to identify all the known Ig/TCR rearrangements as well as additional clonalities, including rare rearrangements characterized by uncommon combinations of variable, diversity, and joining (V-D-J) gene segments, oligoclonal rearrangements, and low represented clones. Upon validation, the capture NGS approach allowed us to identify Ig/TCR clonal markers in 87% of a retrospective cohort (MRD-unknown within the Northern Italy Leukemia Group (NILG)-ALL 09/00 clinical trial) and in 83% of newly-diagnosed ALL cases in which conventional method failed, thus proving its prospective applicability. Finally, we identified gene variants in 94.7% of patients analyzed for mutational status with the same implemented capture assay. The prospective application of this technology could simplify clonality assessment and improve standard assay development for leukemia monitoring, as well as provide information about the mutational status of selected leukemia-related genes, potentially representing new prognostic elements, MRD markers, and targets for specific therapies.

The Expression of P53, MDM2, c-myc, and P14ARF Genes in Newly Diagnosed Acute Lymphoblastic Leukemia Patients

The treatment response of acute lymphoblastic leukemia (ALL) depends on the percentage of lymphoblasts, cytogenetic aberrations, and altered gene expression. The analysis of the gene expression is applicable for determination of risk stratification and prognosis of cancers. c-MYC, P14^ARF, MDM2, and P53 play a vital role in cell survival through a functional network. This study aimed to investigate the expression of these genes, also their correlation with immunophenotypic subtypes of ALL and the percentage of blasts. Real-time PCR was performed for the expression analysis of P53, MDM2, c-MYC, and P14^ARF in the bone marrow or peripheral blood samples of 52 ALL patients and 13 normal samples as controls. The morphological analysis and flow cytometry were carried out to examine the phenotypes and percentage of lymphoblasts. The decreased expression levels of P53 and MDM2 were seen in ALL patients compared with control group. In T cell subgroup of ALL the expression of P14^ARF gene was more decreased among other subgroups. The expression of MDM2 was decreased in ALL patients who were under the age of 16. Based on our study, the interaction between P53 and MDM2 might be more complex and different from reports published in previous studies. Our findings showed that MDM2 is not negatively correlated with P53, at least in our samples. It can be very effective on the current and future studies to use different techniques for analysis of genome, transcriptome, and proteome in definitive risk stratification and prognosis determination.

RAS and TP53 can predict survival in adults with T-cell lymphoblastic leukemia treated with hyper-CVAD

Adult T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous group of acute leukemias that account for about one third of all cases of Philadelphia chromosome (Ph)-negative ALL. Recently, a molecular classifier using the mutational status of NOTCH1, FBXW7, RAS, and PTEN (NFRP) has been shown to distinguish low- vs high-risk groups in adult T-ALL patients treated using the Berlin-Frankfurt-Münster ALL protocol. However, it is unknown if this molecular classifier can stratify adult T-ALL patients treated with hyper-CVAD ± nelarabine. We identified a relatively small cohort of 27 adults with T-ALL who were uniformly treated with hyper-CVAD ± nelarabine with available mutational analysis at time of diagnosis. The most commonly mutated genes in this group were NOTCH1 (52%), NRAS (22%), DNMT3A (19%), KRAS (15%), and TP53 (7%). The NFRP molecular classifier failed to stratify overall survival (OS; P = .84) and relapse-free survival (RFS; P = .18) in this cohort. We developed a new stratification model combining K/NRAS and TP53 mutations as high-risk factors and showed that mutations in these genes predicted poorer OS (P = .03) and RFS (P = .04). While the current study is limited by cohort size, these data suggest that the NFRP molecular classifier might not be applicable to adult T-ALL patients treated with hyper-CVAD ± nelarabine. RAS/TP53 mutation status, however, was useful in risk stratification in adults with T-ALL.

Genetic variants and clinical significance of pediatric acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL), the most common childhood malignancy, is characterized by molecular aberrations. Recently, genetic profiling has been fully investigated on ALL; however, the interaction between its genetic alterations and clinical features is still unclear. Therefore, we investigated the effects of genetic variants on ALL phenotypes and clinical outcomes.

Methods

Targeted exome sequencing technology was used to detect molecular profiling of 140 Chinese pediatric patients with ALL. Correlation of genetic features and clinical outcomes was analyzed.

Results

T-cell ALL (T-ALL) patients had higher initial white blood cell (WBC) count (34.8×10⁹/L), higher incidence of mediastinal mass (26.9%), more relapse (23.1%), and enriched NOTCH1 (23.1%), FBXW7 (23.1%) and PHF6 (11.5%) mutations. Among the 18 recurrently mutated genes, SETD2 and TP53 mutations occurred more in female patients (P=0.041), NOTCH1 and SETD2 mutants were with higher initial WBC counts (≥50×10⁹/L) (P=0.047 and P=0.041), JAK1 mutants were with higher minimal residual disease (MRD) level both on day 19 and day 46 (day 19 MRD ≥1%, P=0.039; day 46 MRD ≥0.01%, P=0.031) after induction chemotherapy. Multivariate analysis revealed that initial WBC counts (≥50×10⁹/L), MLLr, and TP53 mutations were independent risk factors for 3-year relapse free survival (RFS) in ALL. Furthermore, TP53 mutations, age (<1 year or ≥10 years), and MLLr were independently associated with adverse outcome in B-cell ALL (B-ALL).

Conclusions

MLLr and TP53 mutations are powerful predictors for adverse outcome in pediatric B-ALL and ALL. Genetic profiling can contribute to the improvement of prognostication and management in ALL patients.

Chk1 Inhibition Restores Inotuzumab Ozogamicin Citotoxicity in CD22-Positive Cells Expressing Mutant p53

Inotuzumab ozogamicin (IO) is an anti-CD22 calicheamicin immunoconjugate that has been recently approved for the treatment of relapsed or refractory B-Acute Lymphoblastic Leukemia (r/r B-ALL). We employed both immortalized and primary cells derived from CD22-positive lymphoproliferative disorders to investigate the signaling pathways contributing to IO sensitivity or resistance. We found that the drug reduced the proliferation rate of CD22-positive cell lines expressing wild-type p53, but was remarkably less effective on cells exhibiting mutant p53. In addition, CD22-positive cells surviving IO were mostly blocked in the G2/M phase of the cell cycle because of Chk1 activation that, in the presence of a wild-type p53 background, led to p21 induction. When we combined IO with the Chk1 inhibitor UCN-01, we successfully abrogated IO-induced G2/M arrest regardless of the underlying p53 status, indicating that the DNA damage response triggered by IO is also modulated by p53-independent mechanisms. To establish a predictive value for p53 in determining IO responsiveness, we expressed mutant p53 in cell lines displaying the wild-type gene and observed an increase in IO IC₅₀ values. Likewise, overexpression of an inducible wild-type p53 in cells natively presenting a mutant protein decreased their IC₅₀ for IO. These results were also confirmed in primary CD22-positive cells derived from B-ALL patients at diagnosis and from patients with r/r B-ALL. Furthermore, co-treatment with IO and UCN-01 significantly increased cell death in primary cells expressing mutant p53. In summary, our findings suggest that p53 status may represent a biomarker predictive of IO efficacy in patients diagnosed with CD22-positive malignancies.

NOTCH1 Represses MCL-1 Levels in GSI-resistant T-ALL, Making them Susceptible to ABT-263

PURPOSE

Effective targeted therapies are lacking for refractory and relapsed T-cell acute lymphoblastic leukemia (T-ALL). Suppression of the NOTCH pathway using gamma-secretase inhibitors (GSI) is toxic and clinically not effective. The goal of this study was to identify alternative therapeutic strategies for T-ALL.

EXPERIMENTAL DESIGN

We performed a comprehensive analysis of our high-throughput drug screen across hundreds of human cell lines including 15 T-ALL models. We validated and further studied the top hit, navitoclax (ABT-263). We used multiple human T-ALL cell lines as well as primary patient samples, and performed both in vitro experiments and in vivo studies on patient-derived xenograft models.

RESULTS

We found that T-ALL are hypersensitive to navitoclax, an inhibitor of BCL2 family of antiapoptotic proteins. Importantly, GSI-resistant T-ALL are also susceptible to navitoclax. Sensitivity to navitoclax is due to low levels of MCL-1 in T-ALL. We identify an unsuspected regulation of mTORC1 by the NOTCH pathway, resulting in increased MCL-1 upon GSI treatment. Finally, we show that pharmacologic inhibition of mTORC1 lowers MCL-1 levels and further sensitizes cells to navitoclax in vitro and leads to tumor regressions in vivo.

CONCLUSIONS

Our results support the development of navitoclax, as single agent and in combination with mTOR inhibitors, as a new therapeutic strategy for T-ALL, including in the setting of GSI resistance.

B lymphoblastic leukemia/lymphoma: new insights into genetics, molecular aberrations, subclassification and targeted therapy

B lymphoblastic leukemia/lymphoma (B-ALL) is a clonal hematopoietic stem cell neoplasm derived from B-cell progenitors, which mostly occurs in children and adolescents and is regarded as one of top leading causes of death related to malignancies in this population. Despite the majority of patients with B-ALL have fairly good response to conventional chemotherapeutic interventions followed by hematopoietic stem cell transplant for the last decades, a subpopulation of patients show chemo-resistance and a high relapse rate. Adult B-ALL exhibits similar clinical course but worse prognosis in comparison to younger individuals. Ample evidences have shown that the clinical behavior, response rate and clinical outcome of B-ALL rely largely on its genetic and molecular profiles, such as the presence of BCR-ABL1 fusion gene which is an independent negative prognostic predictor. New B-ALL subtypes have been recognized with recurrent genetic abnormalities, including B-ALL with intrachromosomal amplification of chromosome 21 (iAMP21), B-ALL with translocations involving tyrosine kinases or cytokine receptors (“BCR-ABL1-like ALL”). Genome-wide genetic profiling studies on B-ALL have extended our understanding of genomic landscape of B-ALL, and genetic mutations involved in various key pathways have been illustrated. These include CRLF2 and PAX5 alterations, TP53, CREBBP and ERG mutations, characteristic genetic aberrations in BCR-ABL1-like B-ALL and others. The review further provides new insights into clinical implication of the genetic aberrations in regard to targeted therapy development.

TP53 in adult acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is characterized by a great biological and clinical heterogeneity. Despite most adult patients enter complete hematologic remission after induction therapy only 40% survive five or more years. Over the last 20 years, the definition of an accurate biologic leukemia profile and the minimal residual disease evaluation in addition to conventional risk criteria led to a significant improvement for the risk stratification. The alterations of the oncosuppressor gene TP53, including deletions, sequence mutations and defect in its expression due to regulatory defects, define a new important predictor of adverse outcome. More recently, new drugs have been developed with the aim of targeting p53 protein itself or its regulatory molecules, such as Mdm2, and restoring the pathway functionality. Therefore, TP53 alterations should be considered in the diagnostic work-up to identify high risk ALL patients in need of intensive treatment strategies or eligible for new innovative targeted therapies.

TP53 mutation does not confer a poor outcome in adult patients with acute lymphoblastic leukemia who are treated with frontline hyper-CVAD-based regimens

BACKGROUND

Tumor protein 53 (TP53) mutations are uncommon in adult patients with acute lymphoblastic leukemia (ALL) and predict a poor outcome.

METHODS

TP53 mutation analysis was performed in 164 newly diagnosed adult patients with ALL using a combination of targeted amplicon-based next-generation sequencing and Sanger sequencing.

RESULTS

TP53 mutations were detected in 25 patients (15%), with a median allelic frequency of 42.2% (range, 5.6%-93.8%). The majority of mutations were single-nucleotide variants of missense type and involved the DNA-binding domain. TP53-mutated (TP53^mut ) ALL was found to be significantly associated with older age, lower median white blood cell and platelet counts, lower frequency of Philadelphia chromosome and a higher frequency of low hypodiploid karyotype compared with ALL with wild-type TP53 (TP53^wt ). To evaluate the prognostic effect of TP53 mutations, the authors selected 146 patients with B-cell immunophenotype ALL (24 with TP53^mut and 122 with TP53^wt ) who were uniformly treated with frontline hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyper-CVAD)-based regimens; >90% of these individuals also received a monoclonal antibody. Over a median follow-up duration of 15 months, there was no significant difference in the median overall survival, event-free survival, and duration of complete remission noted between patients with TP53^mut ALL and those with TP53^wt ALL.

CONCLUSIONS

Hyper-CVAD-based regimens appear to negate the poor prognostic impact of TP53 mutations in patients with adult B-cell immunophenotype ALL. Cancer 2017;123:3717-24. © 2017 American Cancer Society.

Mutations in TP53 and JAK2 are independent prognostic biomarkers in B-cell precursor acute lymphoblastic leukaemia

BACKGROUND

In B-cell precursor acute lymphoblastic leukaemia (B-ALL), the identification of additional genetic alterations associated with poor prognosis is still of importance. We determined the frequency and prognostic impact of somatic mutations in children and adult cases with B-ALL treated with Spanish PETHEMA and SEHOP protocols.

METHODS

Mutational status of hotspot regions of TP53, JAK2, PAX5, LEF1, CRLF2 and IL7R genes was determined by next-generation deep sequencing in 340 B-ALL patients (211 children and 129 adults). The associations between mutation status and clinicopathological features at the time of diagnosis, treatment outcome and survival were assessed. Univariate and multivariate survival analyses were performed to identify independent prognostic factors associated with overall survival (OS), event-free survival (EFS) and relapse rate (RR).

RESULTS

A mutation rate of 12.4% was identified. The frequency of adult mutations was higher (20.2% vs 7.6%, P=0.001). TP53 was the most frequently mutated gene (4.1%), followed by JAK2 (3.8%), CRLF2 (2.9%), PAX5 (2.4%), LEF1 (0.6%) and IL7R (0.3%). All mutations were observed in B-ALL without ETV6-RUNX1 (P=0.047) or BCR-ABL1 fusions (P<0.0001). In children, TP53mut was associated with lower OS (5-year OS: 50% vs 86%, P=0.002) and EFS rates (5-year EFS: 50% vs 78.3%, P=0.009) and higher RR (5-year RR: 33.3% vs 18.6% P=0.037), and was independently associated with higher RR (hazard ratio (HR)=4.5; P=0.04). In adults, TP53mut was associated with a lower OS (5-year OS: 0% vs 43.3%, P=0.019) and a higher RR (5-year RR: 100% vs 61.4%, P=0.029), whereas JAK2mut was associated with a lower EFS (5-year EFS: 0% vs 30.6%, P=0.035) and a higher RR (5-year RR: 100% vs 60.4%, P=0.002). TP53mut was an independent risk factor for shorter OS (HR=2.3; P=0.035) and, together with JAK2mut, also were independent markers of poor prognosis for RR (TP53mut: HR=5.9; P=0.027 and JAK2mut: HR=5.6; P=0.036).

CONCLUSIONS

TP53mut and JAK2mut are potential biomarkers associated with poor prognosis in B-ALL patients.

Detection of driver and subclonal mutations in myelofibrosis: clinical impact on pharmacologic and transplant based treatment strategies

INTRODUCTION

Myelofibrosis (MF) is the most aggressive form among Philadelphia negative (Ph-) myeloproliferative neoplasms (MPNs). In the last years, the mutational landscape of MF has expanded remarkably by the identification of additional recurrent mutations, called subclonal mutations. Areas covered: Here we describe the available data about the currently identified subclonal mutations and their prognostic value in MF patients. We also review the practical value of including such molecular information in available prognostic models for both outcome prediction and possibly treatment decision with regards to transplant indication. Lastly, we covered the available data on the application of molecular markers for minimal residual disease (MRD) monitoring after transplantation. Expert commentary: The demonstration of the prognostic value of additional mutations suggests to define this molecular profile at diagnosis and when an allogeneic transplant can be advised, particularly in younger patients. The presence of molecular markers might offer the possibility to evaluate the depth of remission and to monitor MRD after transplantation. Prospective clinical studies are needed to validate the use of this molecular data in the routine clinical practice.

Germ line mutations associated with leukemias

Several genetic syndromes have long been associated with a predisposition to the development of leukemia, including bone marrow failure syndromes, Down syndrome, and Li Fraumeni syndrome. Recent work has better defined the leukemia risk and outcomes in these syndromes. Also, in the last several years, a number of other germ line mutations have been discovered to define new leukemia predisposition syndromes, including ANKRD26, GATA2, PAX5, ETV6, and DDX41 In addition, data suggest that a substantial proportion of patients with therapy related leukemias harbor germ line mutations in DNA damage response genes such as BRCA1/2 and TP53 Recognition of clinical associations, acquisition of a thorough family history, and high index-of-suspicion are critical in the diagnosis of these leukemia predisposition syndromes. Accurate identification of patients with germ line mutations associated with leukemia can have important clinical implications as it relates to management of the leukemia, as well as genetic counseling of family members.