CDKN2A/B Alterations Impair Prognosis in Adult BCR-ABL1–Positive Acute Lymphoblastic Leukemia Patients

Allogeneic haematopoietic stem cell transplantation might overcome the poor prognosis of adolescents and adult patients with T-lineage acute lymphoblastic leukaemia and CDKN2 deletion

This study delves into the clinical implications of cyclin-dependent kinase inhibitor 2 (CDKN2) deletion in adult T-lineage acute lymphoblastic leukemia (T-ALL). Among 241 patients included in this study, 57 had CDKN2 deletion and 184 had CDKN2 wild-type (WT), and 165 underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) and 76 did not undergo allo-HSCT. CDKN2 deletion correlated with higher white blood cell count, more high-risk diseases, and complex karyotype. The 5-year overall survival (OS) was 36.8% and 58.2% (P < 0.001), 5-year disease-free survival (DFS) was 47.1% and 59.3% (P = 0.018), and 5-year cumulative incidence of relapse (CIR) was 33.7% and 22.3% (P = 0.019) in patients with CDKN2 deletion and WT, respectively. Multivariate analysis identified CDKN2 deletion as an independent adverse prognostic factor for OS (HR 2.11, P = 0.003). In the CDKN2 deletion subgroup, landmark analysis showed that the 5-year OS was 56.7% and 19% (P = 0.002) for patients who underwent allo-HSCT and those who did not, respectively. And multivariate analysis confirmed the beneficial role of allo-HSCT in OS (HR 0.23, P < 0.001). In conclusion, CDKN2 deletion was associated with a poor prognosis in adult T-ALL, and allo-HSCT might be beneficial for this population.

Gene variation profile and it's potential correlation with clinical characteristics in HBV-associated HCC patients of Sichuan Han nationality in China

OBJECTIVE

To explore the correlation between hepatocellular carcinoma (HCC) gene variation profile and clinical characteristics in Han nationality with HBV infection in Sichuan province.

METHODS

The clinical data and HCC tissues were obtained from the enrolled patients. Whole exome sequencing and bioinformatics analysis were performed on formalin-fixed and paraffin-embedded samples from HCC. Tumor mutational burden (TMB) was measured by an algorithm developed in-house.

RESULTS

Sixteen high-frequency mutated genes with differential expressions were identified by WES. SMG1 gene variation could be positively correlated with satellite lesions. AMY2B and RGPD4 gene mutation seemed to have a greater chance of vascular invasion. The patients with TATDN1 variation have bigger diameters and greater chances of vascular and microvascular invasion (all P < 0.05). Univariate analysis indicated patients with gene TATDN1 variation had worse prognoses both in disease free survival (DFS) and overall survival (OS). In addition, the enrichment analysis showed many pathways, including the cell cycle pathway, viral oncogene pathway, MAPK pathway, PI3K-AKT pathway, etc., may be associated with HCC.

CONCLUSION

This study explores the gene variation profile of HCC patients with HBV infection in Han nationality of Sichuan Province for the first time, which confirmed the existence of some high-frequency mutated genes and the possibility that the gene variations are involved in the tumorigenesis of HCC through multiple signal pathways. Also, patients with TATDN1 wild type showed a trend of better prognosis both in DFS and OS.

p53 Dysregulation in Breast Cancer: Insights on Mutations in the TP53 Network and p53 Isoform Expression

In breast cancer, p53 expression levels are better predictors of outcome and chemotherapy response than TP53 mutation. Several molecular mechanisms that modulate p53 levels and functions, including p53 isoform expression, have been described, and may contribute to deregulated p53 activities and worse cancer outcomes. In this study, TP53 and regulators of the p53 pathway were sequenced by targeted next-generation sequencing in a cohort of 137 invasive ductal carcinomas and associations between the identified sequence variants, and p53 and p53 isoform expression were explored. The results demonstrate significant variability in levels of p53 isoform expression and TP53 variant types among tumours. We have shown that TP53 truncating and missense mutations modulate p53 levels. Further, intronic mutations, particularly polymorphisms in intron 4, which can affect the translation from the internal TP53 promoter, were associated with increased Δ133p53 levels. Differential expression of p53 and p53 isoforms was associated with the enrichment of sequence variants in p53 interactors BRCA1, PALB2, and CHEK2. Taken together, these results underpin the complexity of p53 and p53 isoform regulation. Furthermore, given the growing evidence associating dysregulated levels of p53 isoforms with cancer progression, certain TP53 sequence variants that show strong links to p53 isoform expression may advance the field of prognostic biomarker study in breast cancer.

Frontline combination of ponatinib and hyper-CVAD in Philadelphia chromosome-positive acute lymphoblastic leukemia: 80-months follow-up results

The combination of ponatinib, a third-generation BCR::ABL1 tyrosine kinase inhibitor, with hyper-CVAD chemotherapy resulted in high rates of complete molecular remissions and survival, without the need for stem cell transplantation (SCT) in most patients with Philadelphia chromosome(Ph)-positive acute lymphocytic leukemia (ALL). Confirming these results in a large cohort of patients with longer follow-up would establish this regimen as a new standard of care. Adults with newly diagnosed Ph-positive ALL were treated with the hyper-CVAD regimen. Ponatinib was added as 45 mg daily × 14 during induction, then 45 mg daily continuously (first 37 patients) or 30 mg daily continuously, with dose reduction to 15 mg daily upon achievement of a complete molecular response (CMR; absence of a detectable BCR::ABL1 transcript by quantitative reverse transcription polymerase-chain reaction at a sensitivity of 0.01%). Maintenance therapy consisted of daily ponatinib and vincristine-prednisone monthly for 2 years, followed by daily ponatinib indefinitely. Twelve intrathecal injections of cytarabine alternating with methotrexate were given as central nervous system prophylaxis. The trial is registered on clinicaltrials.gov with the identifier NCT01424982. Eighty-six patients were treated. Their median age was 46 years (range, 21-80). All 68 patients with active disease at the initiation of therapy achieved complete response (CR) The cumulative CMR rate was 86%. Twenty- patients (23%) underwent allogeneic SCT. With a median follow-up of 80 months (range, 16-129 months), the estimated 6-year event-free survival rate was 65% and the overall survival rate was 75%. There was no difference in outcome by performance of allogeneic SCT in first CR. Common grade 3-5 adverse events included infection (n = 80, 93%), increased liver transaminases (n = 26, 31%) and total bilirubin (n = 13, 15%), hypertension (n = 15, 17%), pancreatitis (n = 13, 15%), hemorrhage (n = 12, 13%), and skin rash (n = 9, 10%). Two ponatinib-related deaths from myocardial infarction (3%; at months 2.6 and 4.3, respectively; both in CR) in the first 37 patients treated led to the ponatinib dose-modifications mentioned earlier, with no further ponatinib-related deaths observed. The long-term results of ponatinib and hyper-CVAD continue to demonstrate excellent outcome results and acceptable safety data, indicating that this strategy is another standard of care approach in frontline Ph-positive ALL.

Long Non-Coding RNAs as Novel Targets for Phytochemicals to Cease Cancer Metastasis

Metastasis is a multi-step phenomenon during cancer development leading to the propagation of cancer cells to distant organ(s). According to estimations, metastasis results in over 90% of cancer-associated death around the globe. Long non-coding RNAs (LncRNAs) are a group of regulatory RNA molecules more than 200 base pairs in length. The main regulatory activity of these molecules is the modulation of gene expression. They have been reported to affect different stages of cancer development including proliferation, apoptosis, migration, invasion, and metastasis. An increasing number of medical data reports indicate the probable function of LncRNAs in the metastatic spread of different cancers. Phytochemical compounds, as the bioactive agents of plants, show several health benefits with a variety of biological activities. Several phytochemicals have been demonstrated to target LncRNAs to defeat cancer. This review article briefly describes the metastasis steps, summarizes data on some well-established LncRNAs with a role in metastasis, and identifies the phytochemicals with an ability to suppress cancer metastasis by targeting LncRNAs.

Unraveling the Structural Variations of Early-Stage Mycosis Fungoides—CD3 Based Purification and Third Generation Sequencing as Novel Tools for the Genomic Landscape in CTCL

Mycosis fungoides (MF) is the most common cutaneous T-cell lymphoma (CTCL). At present, knowledge of genetic changes in early-stage MF is insufficient. Additionally, low tumor cell fraction renders calling of copy-number variations as the predominant mutations in MF challenging, thereby impeding further investigations. We show that enrichment of T cells from a biopsy of a stage I MF patient greatly increases tumor fraction. This improvement enables accurate calling of recurrent MF copy-number variants such as ARID1A and CDKN2A deletion and STAT5 amplification, undetected in the unprocessed biopsy. Furthermore, we demonstrate that application of long-read nanopore sequencing is especially useful for the structural variant rich CTCL. We detect the structural variants underlying recurrent MF copy-number variants and show phasing of multiple breakpoints into complex structural variant haplotypes. Additionally, we record multiple occurrences of templated insertion structural variants in this sample. Taken together, this study suggests a workflow to make the early stages of MF accessible for genetic analysis, and indicates long-read sequencing as a major tool for genetic analysis for MF.

Prognostic significance of copy number variation in B-cell acute lymphoblastic leukemia

Copy number variations (CNVs) are widespread in both pediatric and adult cases of B-cell acute lymphoblastic leukemia (B-ALL); however, their clinical significance remains unclear. This review primarily discusses the most prevalent CNVs in B-ALL to elucidate their clinical value and further personalized management of this population. The discovery of the molecular mechanism of gene deletion and the development of targeted drugs will further enhance the clinical prognosis of B-ALL.

Treatment of Adults With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia-From Intensive Chemotherapy Combinations to Chemotherapy-Free Regimens: A Review

Importance

With the advent of potent BCR::ABL1 tyrosine kinase inhibitors (TKIs), Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) is now a relatively favorable-risk acute leukemia. In this review, we discuss the current evidence for frontline therapies of Ph-positive ALL, the major principles that guide therapy, and the progress with chemotherapy-free regimens.

Observations

Incorporating TKIs into the chemotherapy regimens of patients with newly diagnosed Ph-positive ALL has led to improved remission rates, higher probability of reaching allogeneic stem cell transplantation (SCT), and longer survival compared with chemotherapy alone. Early achievement of a complete molecular remission (CMR) is an important end point in Ph-positive ALL and identifies patients who have excellent long-term survival and may not need allogeneic SCT. Second-generation TKIs combined with intensive or low-intensity chemotherapy resulted in higher CMR rates compared with imatinib-based regimens. This translated into better outcomes, with less reliance on allogeneic SCT. To further improve the outcomes, the potent third-generation TKI ponatinib was added to chemotherapy. The combination of hyper-CVAD and ponatinib resulted in an overall CMR rate of 84% and a 5-year survival rate of 73% and 86% among patients who did and did not undergo allogeneic SCT, respectively, suggesting that allogeneic SCT may not be needed with this regimen. The recent chemotherapy-free combination of dasatinib and blinatumomab was safe and effective in patients with newly diagnosed Ph-positive ALL and resulted in an estimated 3-year OS rate of 80%; 50% of patients underwent allogeneic SCT. The chemotherapy-free regimen of ponatinib and blinatumomab resulted in a CMR rate of 86% and a 2-year survival rate of 93%, with no relapses or leukemia-related deaths, and with only 1 patient proceeding to allogeneic SCT.

Conclusions and Relevance

The promising results obtained with the chemotherapy-free regimens of blinatumomab plus TKIs question the role of allogeneic SCT in first remission. Patients with Ph-positive ALL who achieve early and deep molecular responses have excellent long-term outcomes and may not benefit from allogeneic SCT.

Childhood Acute B-Lineage Lymphoblastic Leukemia With CDKN2A/B Deletion Is a Distinct Entity With Adverse Genetic Features and Poor Clinical Outcomes

To further emphasize the clinical-genetic features and prognosis of CDKN2A/B deletions in childhood acute lymphoblastic leukemia (ALL), we retrospectively analyzed 819 consecutive B-ALL patients treated with the Chinese Children's Cancer Group ALL-2015 (CCCG-ALL-2015) protocol, and fluorescence in situ hybridization (FISH) analysis on CDKN2A/B deletion was available for 599 patients. The prevalence of CDKN2A/B gene deletions was 20.2% (121/599) of B-ALL. CDKN2A/B deletions were significantly associated with older age, higher leukocyte counts, a higher percentage of hepatosplenomegaly, and a higher frequency of BCR-ABL (p < 0.05). Those patients achieved similar minimal residual disease (MRD) clearance and complete remission compared to patients without CDKN2A/B deletion. The CDKN2A/B deletions were correlated with inferior outcomes, including a 3-year event-free survival (EFS) rate (69.8 ± 4.6 vs. 89.2 ± 1.6%, p = 0.000) and a 3-year overall survival (OS) rate (89.4% ± 2.9% vs. 94.7% ± 1.1%, p = 0.037). In multivariable analysis, CDKN2A/B deletion was still an independent prognostic factor for EFS in total cohorts (p < 0.05). We also detected a multiplicative interaction between CDKN2A/B deletions and TP53 deletion on dismal prognosis (p-interaction < 0.05). In conclusion, CDKN2A/B deletion is associated with distinct characteristics and serves as a poor prognostic factor in pediatric ALL, especially in TP53 deletion carriers.

Genetic correlates in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia treated with Hyper-CVAD plus dasatinib or ponatinib

Recurring genetic abnormalities have been identified in Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). Among them, IKZF1 deletion was associated with poor prognosis in patients treated with imatinib-based or dasatinib-based regimens. However, the molecular determinants for clinical outcomes in ponatinib-treated patients remain unknown. We systematically analyzed genetic alterations in adults with Ph-positive ALL uniformly treated in clinical trials with dasatinib-based regimens or a ponatinib-based regimen and investigated the molecular determinants for treatment outcomes using pretreatment specimens collected from adults with Ph-positive ALL treated with Hyper-CVAD plus dasatinib or ponatinib. DNA sequencing and SNP microarray were performed and recurrent genetic abnormalities were found in 84% of the patients, among whom IKZF1 deletion was most frequently detected (60%). IKZF1 deletion frequently co-occurred with other copy-number abnormalities (IKZF1^plus, 46%) and was significantly associated with unfavorable overall survival (OS) (false discovery rate < 0.1) and increased cumulative incidence of relapse (p = 0.01). In a multivariate analysis, dasatinib therapy, lack of achievement of 3-month complete molecular response, and the presence of IKZF1^plus status were significantly associated with poor OS. The differential impact of IKZF1^plus was largely restricted to patients given Hyper-CVAD plus ponatinib; dasatinib-based regimens had unfavorable outcomes regardless of the molecular abnormalities.

The functional role of inherited CDKN2A variants in childhood acute lymphoblastic leukemia

OBJECTIVE

Genetic alterations in CDKN2A tumor suppressor gene on chromosome 9p21 confer a predisposition to childhood acute lymphoblastic leukemia (ALL). Genome-wide association studies have identified missense variants in CDKN2A associated with the development of ALL. This study systematically evaluated the effects of CDKN2A coding variants on ALL risk.

METHODS

We genotyped the CDKN2A coding region in 308 childhood ALL cases enrolled in CCCG-ALL-2015 clinical trials by Sanger Sequencing. Cell growth assay, cell cycle assay, MTT-based cell toxicity assay, and western blot were performed to assess the CDKN2A coding variants on ALL predisposition.

RESULTS

We identified 10 novel exonic germline variants, including 6 missense mutations (p.A21V, p.G45A and p.V115L of p16INK4A; p.T31R, p.R90G, and p.R129L of p14ARF) and 1 nonsense mutation and 1 heterozygous termination codon mutation in exon 2 (p16INK4A p.S129X). Functional studies indicate that five novel variants resulted in reduced tumor suppressor activity of p16INK4A, and increased the susceptibility to the leukemic transformation of hematopoietic progenitor cells. Compared to other variants, p.H142R contributes higher sensitivity to CDK4/6 inhibitors.

CONCLUSION

These findings provide direct insight into the influence of inherited genetic variants at the CDKN2A coding region on the development of ALL and the precise clinical application of CDK4/6 inhibitors.

B-cell acute lymphoblastic leukaemia: recent discoveries in molecular pathology, their prognostic significance, and a review of the current classification

Acute lymphoblastic leukaemia (ALL) remains a leading cause of non-traumatic death in children, and the majority of adults diagnosed will succumb to the disease. Recent advances in molecular biology and bioinformatics have enabled more detailed genomic analysis and a better understanding of the molecular biology of ALL. A number of recurrent genomic drivers have recently been described, which not only aid in diagnosis and prognostication, but also may offer opportunities for specific therapeutic targeting. The present review summarises B-ALL genomic pathology at diagnosis, including lesions detectable using traditional cytogenetic methods as well as those detected only through advanced molecular techniques.

Targeting the CDK6 Dependence of Ph+ Acute Lymphoblastic Leukemia

Ph+ ALL is a poor-prognosis leukemia subtype driven by the BCR-ABL1 oncogene, either the p190- or the p210-BCR/ABL isoform in a 70:30 ratio. Tyrosine Kinase inhibitors (TKIs) are the drugs of choice in the therapy of Ph+ ALL. In combination with standard chemotherapy, TKIs have markedly improved the outcome of Ph+ ALL, in particular if this treatment is followed by bone marrow transplantation. However, resistance to TKIs develops with high frequency, causing leukemia relapse that results in <5-year overall survival. Thus, new therapies are needed to address relapsed/TKI-resistant Ph+ ALL. We have shown that expression of cell cycle regulatory kinase CDK6, but not of the highly related CDK4 kinase, is required for the proliferation and survival of Ph+ ALL cells. Comparison of leukemia suppression induced by treatment with the clinically-approved dual CDK4/6 inhibitor palbociclib versus CDK6 silencing revealed that the latter treatment was markedly more effective, probably reflecting inhibition of CDK6 kinase-independent effects. Thus, we developed CDK4/6-targeted proteolysis-targeting chimeras (PROTACs) that preferentially degrade CDK6 over CDK4. One compound termed PROTAC YX-2-107, which degrades CDK6 by recruiting the Cereblon ubiquitin ligase, markedly suppressed leukemia burden in mice injected with de novo or TKI-resistant Ph+ ALL. The effect of PROTAC YX-2-107 was comparable or superior to that of palbociclib. The development of CDK6-selective PROTACs represents an effective strategy to exploit the “CDK6 dependence” of Ph+ ALL cells while sparing a high proportion of normal hematopoietic progenitors that depend on both CDK6 and CDK6 for their survival. In combination with other agents, CDK6-selective PROTACs may be valuable components of chemotherapy-free protocols for the therapy of Ph+ ALL and other CDK6-dependent hematological malignancies.

Integrated analysis of cell cycle-related genes in HR+/HER2- breast cancer

PURPOSE

This study aimed to explore the mutational characteristics and significance of cell cycle-related genes (CCGs) in hormone-receptor positive, human epidermal growth factor receptor 2 negative breast cancer (HR+/HER2- BC).

METHODS

A total of 1668 HR+/HER2- BC patients from the Guangdong Provincial People's Hospital (GDPH) cohort (n = 321) and METABRIC cohort (n = 1347) were included. Tumor samples from HR+/HER2- BC patients were collected for a next-generation sequencing assay in GDPH cohort, including 15 key CCGs. The association between CCGs alterations and overall survival were identified via the Cox regression analysis. The functional roles of the CCGs were explored via the Metascape database.

RESULTS

Based on multivariate Cox regression analysis, a set of five key CCGs (CDK4, CCND1, CDKN1A, CDKN1C, and CHEK2) were identified as independent prognostic variables in HR+/HER2- BC patients. Besides, the five-CCGs-based risk score was used to effectively classify patients into the low-risk and high-risk groups (P < 0.0001). The potential functional pathways of the CCGs included cell cycle, cyclin D associated events in G1, and regulation of G1/S transition of mitotic cell cycle.

CONCLUSION

We performed the integrated analysis of the CCGs in HR+/HER2- BC patients. It has the potential to guide individualized precision oncology therapeutic schemes in HR+/HER2- BC patients.

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.

CDKN2A deletions are associated with poor outcomes in 101 adults with T-cell acute lymphoblastic leukemia

The identification of genetic risk subgroups of T-cell acute lymphoblastic leukemia (T-ALL) may provide evidence for risk stratification and individualized treatment. We investigated the characteristics and prognostic value of tumor suppressor gene CDKN2A deletions in 101 patients with T-ALL. The CDKN2A deletion was present in 23% (23/101) of T-ALL by fluorescence in situ hybridization (FISH). The most common type of CDKN2A deletion was homozygous deletion (70%, 16/23). A lower frequency of CDKN2A deletion was found in patients with early T-cell precursor (ETP) ALL than in patients with non-ETP-ALL (10.4% vs 34.0%; P = .008). Deletion of CDKN2A was significantly associated with younger age (P = .001), higher white blood cell (WBC) count (P < .001) and higher lactate dehydrogenase (LDH) level (P = .002). Patients with CDKN2A deletion had lower 2-year overall survival (OS) and event-free survival (EFS) rates than patients without CDKN2A deletion (2-year OS: 18.6% ± 8.9% vs 47.4% ± 6.2%, P = .032; EFS: 16.4 ± 8.3 vs 38.6 ± 5.9%, P = .022). In multivariable analysis, CDKN2A deletion was an independent adverse prognostic factor for OS (P = .016). In conclusion, adult T-ALL patients with CDKN2A deletion had a poor prognosis, and these patients might benefit from intensive chemotherapy or allogeneic hematopoietic stem-cell transplantation.

The Yin and Yang-Like Clinical Implications of the CDKN2A/ARF/CDKN2B Gene Cluster in Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a malignant clonal expansion of lymphoid hematopoietic precursors that exhibit developmental arrest at varying stages of differentiation. Similar to what occurs in solid cancers, transformation of normal hematopoietic precursors is governed by a multistep oncogenic process that drives initiation, clonal expansion and metastasis. In this process, alterations in genes encoding proteins that govern processes such as cell proliferation, differentiation, and growth provide us with some of the clearest mechanistic insights into how and why cancer arises. In such a scenario, deletions in the 9p21.3 cluster involving CDKN2A/ARF/CDKN2B genes arise as one of the oncogenic hallmarks of ALL. Deletions in this region are the most frequent structural alteration in T-cell acute lymphoblastic leukemia (T-ALL) and account for roughly 30% of copy number alterations found in B-cell-precursor acute lymphoblastic leukemia (BCP-ALL). Here, we review the literature concerning the involvement of the CDKN2A/B genes as a prognosis marker of good or bad response in the two ALL subtypes (BCP-ALL and T-ALL). We compare frequencies observed in studies performed on several ALL cohorts (adult and child), which mainly consider genetic data produced by genomic techniques. We also summarize what we have learned from mouse models designed to evaluate the functional involvement of the gene cluster in ALL development and in relapse/resistance to treatment. Finally, we examine the range of possibilities for targeting the abnormal function of the protein-coding genes of this cluster and their potential to act as anti-leukemic agents in patients.

Role of BCR-ABL1 isoforms on the prognosis of Philadelphia chromosome positive acute lymphoblastic leukemia in the tyrosine kinase inhibitor era: A meta-analysis

BCR-ABL1 fusion gene is the driver mutation of Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL). Although the prognostic value of BCR-ABL1 isoforms in Ph+ ALL patients has been investigated in numerous studies in the tyrosine kinase inhibitor (TKI) era, the results were still conflicting. Hence we performed herein the meta-analysis to comprehensively assess the impact of BCR-ABL1 isoforms on the clinical outcomes of Ph+ ALL patients. Systematic literature review was conducted in PubMed, Embase, and Cochrane databases with the data access date up to June 15, 2020. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated with fixed-effects or random-effects models. Furthermore, subgroup analyses were performed to assess the robustness of the associations. Nine studies with a total number of 1582 patients were eligible for this meta-analysis. Combined HRs suggested that p210 was slightly associated with inferior event-free survival (EFS) (HR = 1.34, 95% CI 1.05–1.72). The overall survival (OS) was not significantly affected (HR = 1.15, 95% CI 0.92–1.45). In subgroup analyses, the HRs showed a trend toward adverse impact of p210 on clinical outcomes. However, the confidence intervals were not crossing the null value only in a minority of subgroups including Caucasian studies, first-generation TKI treated cohort and transplant cohort. Our findings suggested that p210 might pose a mild adverse impact on the EFS of Ph+ ALL patients. This effect might be compromised by the use of second- or third-generation TKIs. Further studies are needed to verify our conclusions.

Curing Ph+ ALL: assessing the relative contributions of chemotherapy, TKIs, and allogeneic stem cell transplant

The understanding and treatment of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia have changed rapidly in the past 10 years. The outcome is equally as good as for Ph- disease, and with targeted tyrosine kinase inhibitor therapies in addition to chemotherapy, the novel immunotherapy approaches, and the extension of allogeneic hematopoietic stem cell transplant (allo-HCT) to older individuals, there is the potential to exceed this outcome. There is particular interest in reducing chemotherapy exposure and considering for whom allo-HCT can be avoided. However, the patient population that can help test these options in clinical trials is limited in number, and the available evidence is often derived from single-arm studies. This paper summarizes outcomes achieved with recent approaches to de novo Ph+ acute lymphoblastic leukemia in the postimatinib era and helps integrate all the available information to assist the reader to make informed choices for patients in an increasingly complex field.

Clinical, pathological, and genomic features of EWSR1-PATZ1 fusion sarcoma

Molecular diagnostics of sarcoma subtypes commonly involve the identification of characteristic oncogenic fusions. EWSR1-PATZ1 is a rare fusion partnering in sarcoma, with few cases reported in the literature. In the current study, a series of 11 cases of EWSR1-PATZ1 fusion positive malignancies are described. EWSR1-PATZ1-related sarcomas occur across a wide age range and have a strong predilection for chest wall primary site. Secondary driver mutations in cell-cycle genes, and in particular CDKN2A (71%), are common in EWSR1-PATZ1 sarcomas in this series. In a subset of cases, an extended clinical and histopathological review was performed, as was confirmation and characterization of the fusion breakpoint revealing a novel intronic pseudoexon sequence insertion. Unified by a shared gene fusion, EWSR1-PATZ1 sarcomas otherwise appear to exhibit divergent morphology, a polyphenotypic immunoprofile, and variable clinical behavior posing challenges for precise classification.

Antileukemia Effects of Notch-Mediated Inhibition of Oncogenic PLK1 in B-Cell Acute Lymphoblastic Leukemia

In B-cell acute lymphoblastic leukemia (B-ALL), activation of Notch signaling leads to cell-cycle arrest and apoptosis. We aimed to harness knowledge acquired by understanding a mechanism of Notch-induced cell death to elucidate a therapeutically viable target in B-ALL. To this end, we identified that Notch activation suppresses Polo-like kinase 1 (PLK1) in a B-ALL-specific manner. We identified that PLK1 is expressed in all subsets of B-ALL and is highest in Philadelphia-like (Ph-like) ALL, a high-risk subtype of disease. We biochemically delineated a mechanism of Notch-induced PLK1 downregulation that elucidated stark regulation of p53 in this setting. Our findings identified a novel posttranslational cascade initiated by Notch in which CHFR was activated via PARP1-mediated PARylation, resulting in ubiquitination and degradation of PLK1. This led to hypophosphorylation of MDM2Ser260, culminating in p53 stabilization and upregulation of BAX. shRNA knockdown or pharmacologic inhibition of PLK1 using BI2536 or BI6727 (volasertib) in B-ALL cell lines and patient samples led to p53 stabilization and cell death. These effects were seen in primary human B-ALL samples in vitro and in patient-derived xenograft models in vivo These results highlight PLK1 as a viable therapeutic target in B-ALL. Efficacy of clinically relevant PLK1 inhibitors in B-ALL patient-derived xenograft mouse models suggests that use of these agents may be tailored as an additional therapeutic strategy in future clinical studies.

SOX6 blocks the proliferation of BCR-ABL1+ and JAK2V617F+ leukemic cells

SOX6 is a HMG-box transcription factor expressed in a wide range of tissues. Recent data show that SOX6 expression is altered in different cancers, in the majority of cases being downregulated. To date, no data are available about SOX6 role in hematological malignancies. Here we demonstrate that SOX6 overexpressing BCR-ABL1⁺ B-ALL cells are unable to promote leukemia in a mouse model. Starting from this observation, we extended our study to a panel of human leukemic cells carrying genetic lesions distinctive of different types of leukemias and myeloproliferative disorders (the BCR-ABL1 translocation and the JAK2V617F amino acid substitution) to dissect the cellular events induced by SOX6. The inhibition of proliferation is the invariant outcome of SOX6 overexpression but it is achieved via two different cellular responses: terminal differentiation in erythroid-biased cells, irrespectively of their mutation, and apoptosis in megakaryocytic-primed and lymphoid cells. Within this context, cells carrying the highest copy number of the JAK2V617F allele better counteract the SOX6-imposed growth arrest. The interrogation of the GEPIA (Gene Expression Profiling Interactive Analysis) human dataset reveals that SOX6 is downregulated in a cohort of AML patients, uncovering a wide anti-proliferative role of SOX6 in a variety of mutant backgrounds.

Prognostic significance of CDKN2A/B deletions in acute lymphoblastic leukaemia: a meta-analysis

BACKGROUND

Cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) genes are frequently altered in acute lymphoblastic leukaemia (ALL) patients. The aim of this meta-analysis was to comprehensively assess the prognostic value of CDKN2A/B deletions in ALL patients.

METHODS

Systematic literature review was conducted in PubMed, Embase and Cochrane databases up to July 2018. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated with fixed-effects or random-effects models.

RESULTS

A total of thirteen studies including 2857 patients were eligible for this meta-analysis. Combined HRs suggested that CDKN2A/B deletions were poor prognostic factors for both overall survival (OS) (HR = 2.15, 95% CI 1.82-2.54) and event-free survival (EFS)/disease-free survival (DFS)/relapse-free survival (RFS) (HR = 2.16, 95% CI 1.73-2.69). The adverse impact remained significant in both adult and paediatric ALL patients, and also in subgroups by ethnicity, ALL type, detection method of CDKN2A/B deletions, statistical method and endpoint.

CONCLUSIONS

Our findings suggested that CDKN2A/B deletions were associated with poor prognosis independently in both adult and childhood ALL patients. Inclusion of CDKN2A/B status may further improve the risk stratification of ALL patients. Key Messages Although numerous studies have explored the prognostic significance of cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) deletions in acute lymphoblastic leukaemia (ALL) patients, the results remain conflicting. In this meta-analysis, we found that CDKN2A/B deletions were independent poor prognostic markers for both adult and paediatric ALL patients. Our findings justify the inclusion of CDKN2A/B status in the risk stratification of ALL patients.

Combination of hyper-CVAD with ponatinib as first-line therapy for patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia: long-term follow-up of a single-centre, phase 2 study

BACKGROUND

The combination of chemotherapy and ponatinib in Philadelphia chromosome-positive acute lymphoblastic leukaemia has the potential to be a new standard of care for the disease; however, long-term efficacy and safety data are needed. Our aim was to evaluate the long-term efficacy and safety of this regimen in patients with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukaemia in this ongoing phase 2 trial.

METHODS

In our single-centre, phase 2, single-arm trial in the USA, adult patients with previously untreated Philadelphia chromosome-positive acute lymphoblastic leukaemia were sequentially enrolled. Eligible patients had newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukaemia, were aged 18 years or older, had an Eastern Cooperative Oncology Group performance status of 2 or less, a left ventricular ejection fraction above 50%, and adequate hepatic and renal function (serum bilirubin ≤3·0 mg/dL and serum creatinine ≤3·0 mg/dL, unless higher levels were believed to be due to leukaemia at the discretion of the investigator). Patients received eight cycles of 21 days, alternating between two drug combinations: hyper-fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyper-CVAD) and high-dose methotrexate and cytarabine. Ponatinib was given orally at 45 mg per day for the first 14 days of cycle 1 then continuously at 45 mg per day for the subsequent cycles. After 37 patients were treated, the protocol was amended to reduce the dose of ponatinib to 30 mg per day at cycle 2, with further reduction to 15 mg once a complete molecular response (defined as absence of quantifiable BCR-ABL1 transcripts) was achieved. Patients in complete remission received maintenance with ponatinib daily (30 mg or 15 mg) indefinitely, and with vincristine (2 mg intravenously on day 1) and prednisone (200 mg orally on days 1-5) monthly for 2 years. The primary endpoint was 3-year event-free survival in the intention-to-treat population. The trial is registered at ClinicalTrials.gov, number NCT01424982, and is ongoing and still enrolling patients.

FINDINGS

76 patients with a median age of 47 years (IQR 39-61) were enrolled and treated between Nov 19, 2011, and April 4, 2018. The 3-year event-free survival was 70% (95% CI 56-80). The most common grade 3 or 4 adverse events were infection (n=65, 86%), increased transaminases (n=24, 32%), increased bilirubin (n=13, 17%), pancreatitis (n=13, 17%), hypertension (n=12, 16%), bleeding (n=10, 13%), and skin rash (n=9, 12%). Six patients died while still on study treatment. Three patients (4%) died from infection and one (1%) from haemorrhage. Two patients died from myocardial infarction related to early ponatinib use; neither death occurred after protocol revision.

INTERPRETATION

The combination of chemotherapy with ponatinib is effective in achieving long-term remission in patients with newly diagnosed Philadelphia chromosome-positive  acute lymphoblastic leukaemia. This regimen could represent a new standard of care for this population. A randomised, phase 3 study to evaluate the efficacy of this combination compared with chemotherapy plus earlier-generation tyrosine-kinase inhibitors is warranted.

FUNDING

Takeda Oncology.

Deletion of CDKN2A/B is associated with inferior relapse free survival in pediatric B cell acute lymphoblastic leukemia

Considering conflicting data on CDKN2A/B deletion in ALL, this study to assess its prognostic significance as an independent marker in a total of 96 pediatric B and T-ALL cases was planned. The overall frequency of CDKN2A/B deletion was 44% (n = 43) with 36% (30/83) in B-ALL and 100% (13/13) in T-ALL. CDKN2A/B deletion was significantly associated with high WBC count (p = .002) and National Cancer Institute risk (p = .01) in B-ALL. Importantly, CDKN2A/B deletion cases had poor EFS of 42% at 28 months compared to EFS of 90% in rest (p = .0004). Further, relapse free survival was only 56% for cases with CDKN2A/B deletions (n = 25), compared to 100% in control group (p = .001). Moreover, CDKN2A/B deletion was the only risk factor associated with early relapse (p = .01) compared to IKZF1 deletion (p = .73) or occurrence of BCR-ABL1 fusion transcript (p = .26). Thus our study data highlights potential prognostic role of CDKN2A/B deletions in early disease stratification in pediatric B-ALL.

Treating hematological malignancies with drugs inhibiting ribosome biogenesis: when and why

It is well known that chemotherapy can cure only some cancers in advanced stage, mostly those with an intact p53 pathway. Hematological cancers such as lymphoma and certain forms of leukemia are paradigmatic examples of such scenario. Recent evidence indicates that the efficacy of many of the alkylating and intercalating agents, antimetabolites, topoisomerase, and kinase inhibitors used in cancer therapy is largely due to p53 stabilization and activation consequent to the inhibition of ribosome biogenesis. In this context, innovative drugs specifically hindering ribosome biogenesis showed preclinical activity and are currently in early clinical development in hematological malignancies. The mechanism of p53 stabilization after ribosome biogenesis inhibition is a multistep process, depending on specific factors that can be altered in tumor cells, which can affect the antitumor efficacy of ribosome biogenesis inhibitors (RiBi). In the present review, the basic mechanisms underlying the anticancer activity of RiBi are discussed based on the evidence deriving from available preclinical and clinical studies, with the purpose of defining when and why the treatment with drugs inhibiting ribosomal biogenesis could be highly effective in hematological malignancies.

Distinct age-associated molecular profiles in acute myeloid leukemia defined by comprehensive clinical genomic profiling

Large scale comprehensive genomic profiling (CGP) has led to an improved understanding of oncogenic mutations in acute myeloid leukemia (AML), as well as identification of alterations that can serve as targets for potential therapeutic intervention. We sought to gain insight into age-associated variants in AML through comparison of extensive DNA and RNA-based GP results from pediatric and adult AML. Sequencing of 932 AML specimens (179 pediatric (age 0-18), 753 adult (age ≥ 19)) from diagnostic, relapsed, and refractory times points was performed. Comprehensive DNA (405 genes) and RNA (265) sequencing to identify a variety of structural and short variants was performed. We found that structural variants were highly prevalent in the pediatric cohort compared to the adult cohort (57% vs. 30%; p < 0.001), with certain structural variants detected only in the pediatric cohort. Fusions were the most common structural variant and were highly prevalent in AML in very young children occurring in 68% of children < 2 years of age. We observed an inverse trend in the prevalence of fusions compared to the average number of mutations per patient. In contrast to pediatric AML, adult AML was marked by short variants and multiple mutations per patient. Mutations that were common in adult AML were much less common in the adolescent and young adult cohort and were rare or absent in the pediatric cohort. Clinical CGP demonstrates the biologic differences in pediatric vs. adult AML that have significant therapeutic impacts on prognosis, therapeutic allocation, disease monitoring, and the use of more targeted therapies.

Prognostic significance of copy number alterations detected by multi-link probe amplification of multiple genes in adult acute lymphoblastic leukemia

The multiplex ligation-dependent probe amplification (MLPA) method was used to detect the copy number alterations (CNAs) of IKAROS family zinc finger 1 (IKZF1), paired box 5 (PAX5), ETS variant 6 (ETV6), RB transcriptional corepressor 1 (RB1), BTG anti-proliferation factor 1 (BTG1), early B-cell factor 1 (EBF1), cyclin dependent kinase inhibitor 2A/2B (CDKN2A/2B) and cytokine receptor like factor 2 (CRLF2) genes in 87 adults with acute lymphoblastic leukemia (ALL) in China. The effects of CNAs on prognosis were analyzed. Gene deletions were detected in 58/87 (66.7%) ALL patients. The most common deletions were observed in the following genes: IKZF1 (40.6%), CDKN2A (31.9%), CDKN2B (29%), PAX5 (21.7%), RB1 (14.5%) and BTG1 (10.1%). B cell-ALL (B-ALL) patients with CDKN2A/2B deletions exhibited poor 2-year overall survival (OS; P=0.055) and relapse-free survival (RFS; P=0.054) rates. CDKN2A/2B deletions were associated with poor 2-year OS (P=0.045) and RFS (P=0.071) rates in Philadelphia chromosome positive (Ph⁺) B-ALL patients, as well as in the high risk (HR) B-ALL group (P=0.037 and P=0.047, respectively). Patients with PAX5 deletions displayed poor 2-year OS (P=0.004) and RFS (P=0.016) rates in Philadelphia chromosome negative (Ph^-) B-ALL patients. Patients with ≥3 gene deletions exhibited a poorer prognosis than other patients (OS, P=0.001; RFS, 0.002).

Oncogenic kinase fusions: an evolving arena with innovative clinical opportunities

Cancer biology relies on intrinsic and extrinsic deregulated pathways, involving a plethora of intra-cellular and extra-cellular components. Tyrosine kinases are frequently deregulated genes, whose aberrant expression is often caused by major cytogenetic events (e.g. chromosomal translocations). The resulting tyrosine kinase fusions (TKFs) prompt the activation of oncogenic pathways, determining the biological and clinical features of the associated tumors. First reported half a century ago, oncogenic TKFs are now found in a large series of hematologic and solid tumors. The molecular basis of TKFs has been thoroughly investigated and tailored therapies against recurrent TKFs have recently been developed. This review illustrates the biology of oncogenic TKFs and their role in solid as well as hematological malignancies. We also address the therapeutic implications of TKFs and the many open issues concerning their clinical impact.

Targeting CDK6 and BCL2 Exploits the "MYB Addiction" of Ph+ Acute Lymphoblastic Leukemia

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ ALL) is currently treated with BCR-ABL1 tyrosine kinase inhibitors (TKI) in combination with chemotherapy. However, most patients develop resistance to TKI through BCR-ABL1-dependent and -independent mechanisms. Newly developed TKI can target Ph⁺ ALL cells with BCR-ABL1-dependent resistance; however, overcoming BCR-ABL1-independent mechanisms of resistance remains challenging because transcription factors, which are difficult to inhibit, are often involved. We show here that (i) the growth of Ph⁺ ALL cell lines and primary cells is highly dependent on MYB-mediated transcriptional upregulation of CDK6, cyclin D3, and BCL2, and (ii) restoring their expression in MYB-silenced Ph⁺ ALL cells rescues their impaired proliferation and survival. Levels of MYB and CDK6 were highly correlated in adult Ph⁺ ALL (P = 0.00008). Moreover, Ph⁺ ALL cells exhibited a specific requirement for CDK6 but not CDK4 expression, most likely because, in these cells, CDK6 was predominantly localized in the nucleus, whereas CDK4 was almost exclusively cytoplasmic. Consistent with their essential role in Ph⁺ ALL, pharmacologic inhibition of CDK6 and BCL2 markedly suppressed proliferation, colony formation, and survival of Ph⁺ ALL cells ex vivo and in mice. In summary, these findings provide a proof-of-principle, rational strategy to target the MYB "addiction" of Ph⁺ ALL.Significance: MYB blockade can suppress Philadelphia chromosome-positive leukemia in mice, suggesting that this therapeutic strategy may be useful in patients who develop resistance to imatinib and other TKIs used to treat this disease. Cancer Res; 78(4); 1097-109. ©2017 AACR.

Targeting the p53-MDM2 interaction by the small-molecule MDM2 antagonist Nutlin-3a: a new challenged target therapy in adult Philadelphia positive acute lymphoblastic leukemia patients

MDM2 is an important negative regulator of p53 tumor suppressor. In this study, we sought to investigate the preclinical activity of the MDM2 antagonist, Nutlin-3a, in Philadelphia positive (Ph+) and negative (Ph-) leukemic cell line models, and primary B-acute lymphoblastic leukemia (ALL) patient samples. We demonstrated that Nutlin-3a treatment reduced viability and induced p53-mediated apoptosis in ALL cells with wild-type p53 protein, in a time and dose-dependent manner, resulting in the increased expression of pro-apoptotic proteins and key regulators of cell cycle arrest. The dose-dependent reduction in cell viability was confirmed in primary blast cells from B-ALL patients, including Ph+ ALL resistant patients carrying the T315I BCR-ABL1 mutation. Our findings provide a strong rational for further clinical investigation of Nutlin-3a in Ph+ and Ph- ALL.

Aberrant DNA methylation of key genes and Acute Lymphoblastic Leukemia

DNA methylation is a dynamic process influencing gene expression by altering either coding or non-coding loci. Despite advances in treatment of Acute Lymphoblastic Leukemia (ALL); relapse occurs in approximately 20% of patients. Nowadays, epigenetic factors are considered as one of the most effective mechanisms in pathogenesis of malignancies. These factors are reversible elements which can be potentially regarded as therapy targets and disease prognosis. DNA methylation, which primarily serves as transcriptional suppressor, mostly occurs in CpG islands of the gene promoter regions. This was shown as a key epigenetic factor in inactivating various tumor suppressor genes during cancer initiation and progression. We aimed to review methylation status of key genes involved in hematopoietic malignancies such as IKZF1, CDKN2B, TET2, CYP1B1, SALL4, DLC1, DLX family, TP73, PTPN6, and CDKN1C; and their significance in pathogenesis of ALL. The DNA methylation alterations in promoter regions of the genes have been shown to play crucial roles in tumorigenesis. Methylation -based inactivation of these genes has also been reported as associated with prognosis in acute leukemia. In this review, we also addressed the association of gene expression and methylation pattern in ALL patients.

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.

Molecular profiling of gene copy number abnormalities in key regulatory genes in high-risk B-lineage acute lymphoblastic leukemia: frequency and their association with clinicopathological findings in Indian patients

Genes related to key cellular pathways are frequently altered in B cell ALL and are associated with poor survival especially in high-risk (HR) subgroups. We examined gene copy number abnormalities (CNA) in 101 Indian HR B cell ALL patients and their correlation with clinicopathological features by multiplex ligation-dependent probe amplification. Overall, CNA were detected in 59 (59%) cases, with 26, 10 and 23% of cases harboring 1, 2 or +3 CNA. CNA were more prevalent in BCR-ABL1 (60%), pediatric (64%) and high WCC (WBC count) (63%) patients. Frequent genes deletions included CDNK2A/B (26%), IKZF1 (25%), PAX5 (14%), JAK2 (7%), BTG1 (6%), RB1 (5%), EBF1 (4%), ETV6 (4%), while PAR1 region genes were predominantly duplicated (20%). EBF1 deletions selectively associated with adults, IKZF1 deletions occurred frequently in high WCC and BCR-ABL1 cases, while PAR1 region gains significantly associated with MLL-AF4 cases. IKZF1 haploinsufficiency group was predominant, especially in adults (65%), high WCC (60%) patients and BCR-ABL1-negative (78%) patients. Most cases harbored multiple concurrent CNA, with IKZF1 concomitantly occurring with CDNK2A/B, PAX5 and BTG1, while JAK2 occurred with CDNK2A/B and PAX5. Mutually exclusive CNA included ETV6 and IKZF1/RB1, and EBF1 and JAK2. Our results corroborate with global reports, aggregating molecular markers in Indian HR B-ALL cases. Integration of CNA data from rapid methods like MLPA, onto background of existing gold-standard methods detecting significant chromosomal abnormalities, provides a comprehensive genetic profile in B-ALL.

Allogeneic hematopoietic stem cell transplantation improves the prognosis of p16-deleted adult patients with acute lymphoblastic leukemia

Aim: The prognostic value of CDKN2A inactivation in adult patients with acute lymphoblastic leukemia (ALL) is still under debate, and the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult ALL with p16 deletion remains to be evaluated. Materials & methods: This study analyzed the clinical implications of p16 deletion in adult ALL and investigated the efficacy of allo-HSCT in patients with p16 deletion. Results: Deletion of p16 was identified in 38.4% of the adult ALL patients, and the prevalences of hemizygous deletion, homozygous deletion and mixed hemi/homozygous of p16 were 22.1, 11.6 and 5.5%, respectively. The prevalence of p16 deletion was 39.7% in B-lineage ALL and 33.3% in T-lineage ALL. Deletion of p16 was significantly associated with higher white blood cell count (p = 0.032) and lower platelets (p = 0.023) but was not related to age, sex, percentage of bone marrow blasts, hepatosplenomegaly, CNS leukemia rate, first complete remission and relapse rate (p > 0.05). Deletion of p16 was significantly correlated with poor outcome in terms of event-free survival (EFS; p = 0.028) and overall survival (OS; p = 0.033). Twenty-two of the 33 patients with p16 deletion received allo-HSCT treatment. Patients with p16 deletion after allo-HSCT experienced higher EFS and OS than those without (52.9 vs 0%, p < 0.001; 46.8 vs 29.1%, p = 0.01, respectively). Multivariate analysis found CNS leukemia and poor response to induction chemotherapy to be the risk factors for EFS and OS, whereas no deletions of p16 and allo-HSCT were favorable factors. Conclusion: Deletion of p16 is a strong adverse prognostic factor in adult ALL. Testing for p16 alterations at diagnosis may help in risk stratification, and we propose to implement testing for p16 deletion in future treatment protocols.

P53-MDM2 Pathway: Evidences for A New Targeted Therapeutic Approach in B-Acute Lymphoblastic Leukemia

The tumor suppressor p53 is a canonical regulator of different biological functions, like apoptosis, cell cycle arrest, DNA repair, and genomic stability. This gene is frequently altered in human tumors generally by point mutations or deletions. Conversely, in acute lymphoblastic leukemia (ALL) genomic alterations of TP53 are rather uncommon, and prevalently occur in patients at relapse or with poor prognosis. On the other hand, p53 pathway is often compromised by the inactivation of its regulatory proteins, as MDM2 and ARF. MDM2 inhibitor molecules are able to antagonize p53-MDM2 interaction allowing p53 to exert tumor suppressor transcriptional regulation and to induce apoptotic pathways. Recent preclinical and clinical studies propose that MDM2 targeted therapy represents a promising anticancer strategy restoring p53 dependent mechanisms in ALL disease. Here, we discussed the use of new small molecule targeting p53 pathways as a promising drug target therapy in ALL.

Germline CDKN2A Mutation Status and Survival in Familial Melanoma Cases

BACKGROUND

Germline mutations in CDKN2A have been associated with increased risk of melanoma and tobacco-related cancers in respiratory and upper digestive tissues. In CDKN2A wild-type (wt) melanoma families, other known high-risk, melanoma-predisposing mutations are rare, and no increased risk has been observed for nonskin cancers in this group. This study is the first to compare survival in germline CDKN2A mutated (mut) and nonmutated melanoma cases.

METHODS

Melanoma-prone families participating in this study were identified through a nationwide predictive program starting in 1987. Information on cancer diagnoses (types, stages, and dates) and deaths (causes and dates) were obtained through the Swedish Cancer Registry and Cause of Death Registry. Kaplan Meier and Cox proportional hazards regression models were used to assess survival in CDKN2A(mut) (n = 96) and CDKN2A(wt) (n = 377) familial melanoma cases and in matched sporadic melanoma cases (n = 1042). All statistical tests were two-sided.

RESULTS

When comparing CDKN2A(mut) and CDKN2A(wt) melanoma cases, after adjusting for age, sex, and T classification, CDKN2A(mut) had worse survival than melanoma (hazard ratio [HR] = 2.50, 95% confidence interval [CI] = 1.49 to 4.21) and than nonmelanoma cancers (HR = 7.77, 95% CI = 3.65 to 16.51). Compared with matched sporadic cases, CDKN2A(mut) cases had statistically significantly worse survival from both melanoma and nonmelanoma cancers while no differences in survival were seen in CDKN2A(wt) compared with sporadic cases.

CONCLUSIONS

CDKN2A(mut) cases had statistically significantly worse survival than nonmelanoma cancers and, intriguingly, also from melanoma, compared with melanoma cases with no CDKN2A mutations. Further studies are required to elucidate possible mechanisms behind increased carcinogen susceptibility and the more aggressive melanoma phenotype in CDKN2A mutation carriers.

Biallelic loss of CDKN2A is associated with poor response to treatment in pediatric acute lymphoblastic leukemia

The inactivation of tumor suppressor genes located within 9p21 locus (CDKN2A, CDKN2B) occurs in up to 30% of children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), but its independent prognostic significance remains controversial. In order to investigate the prognostic impact of deletions and promoter methylation within 9p21, 641 children with newly diagnosed BCP-ALL using methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) were investigated. A total of 169 (26.4%) microdeletions in 9p21 were detected, of which 71 were homozygous. Patients with CDKN2A homozygous deletions were older at diagnosis (p < .001), more frequently steroid resistant (p = .049), had higher WBC count (p < .001), higher MRD at Day 15 (p = .013) and lower relapse-free survival [p = .028, hazard ratio: 2.28 (95% confidence interval: 1.09-4.76)] than patients without these alterations. CDKN2A homozygous deletions coexisted with IKZF1 and PAX5 deletions (p < .001). In conclusion, CDKN2A homozygous deletions, but not promoter methylation, are associated with poor response to treatment and increased relapse risk of pediatric BCP-ALL.

DNA methylation and leukemia susceptibility in China: Evidence from an updated meta-analysis

Mounting evidence supports a role for DNA methylation in the pathogenesis of leukemia; however, there no overview of these results in the Chinese population. The present study performed a comprehensive meta-analysis to establish candidate genes with an altered methylation status in Chinese leukemia patients. Eligible studies were identified through searching the National Center of Biotechnology Information PubMed and Wanfang databases. Studies were pooled and overall odds ratios with corresponding confidence intervals were calculated. A total of 4,325 leukemia patients and 2,010 controls from 94 studies on 53 genes were included in this meta-analysis, and 47 genes were found to be aberrantly methylated in leukemia patients. A further subgroup meta-analysis by leukemia subtype demonstrated that hypermethylation of 5 genes, namely cyclin-dependent kinase (CDKN)2A, DNA-binding protein inhibitor-4, CDKN2B, glioma pathogenesis-related protein 1 and p73, contributed to the risk of various subtypes of leukemia. In addition, a strong association between CDKN2A and leukemia was identified in Chinese (P<0.00001) but not in European patients. The aberrantly methylated genes identified in the present meta-analysis may help elucidate the mechanisms underlying the development of leukemia in Chinese patients.

Pharmacological activation of wild-type p53 in the therapy of leukemia

The tumor suppressor p53 is inactivated by mutations in the majority of human solid tumors. Conversely, p53 mutations are rare in leukemias and are only observed in a small fraction of the patient population, predominately in patients with complex karyotype acute myeloid leukemia or hypodiploid acute lymphoblastic leukemia. However, the loss of p53 function in leukemic cells is often caused by abnormalities in p53-regulatory proteins, including overexpression of MDM2/MDMX, deletion of CDKN2A/ARF, and alterations in ATM. For example, MDM2 inhibits p53-mediated transcription, promotes its nuclear export, and induces proteasome-dependent degradation. The MDM2 homolog MDMX is another direct regulator of p53 that inhibits p53-mediated transcription. Several small-molecule inhibitors and stapled peptides targeting MDM2 and MDMX have been developed and have recently entered clinical trials. The clinical trial results of the first clinically used MDM2 inhibitor, RG7112, illustrated promising p53 activation and apoptosis induction in leukemia cells as proof of concept. Side effects of RG7112 were most prominent in suppression of thrombopoiesis and gastrointestinal symptoms in leukemia patients. Predictive biomarkers for response to MDM2 inhibitors have been proposed, but they require further validation both in vitro and in vivo so that the accumulated knowledge concerning pathological p53 dysregulation in leukemia and novel molecular-targeted strategies to overcome this dysregulation can be translated safely and efficiently into novel clinical therapeutics.

Risk stratification of T-cell Acute Lymphoblastic Leukemia patients based on gene expression, mutations and copy number variation

Gene expression, copy number variations (CNV), mutations and survival were studied to delineate TCRγδ+T-cell acute lymphoblastic leukemia (T-ALL) as a distinct subgroup from TCRαβ+T-ALL. Gene Ontology analysis showed that differential regulation of genes involved in pathways for leukemogenesis, apoptosis, cytokine-cytokine receptor interaction and antigen processing/presentation may offer a survival benefit to TCRγδ+T-ALL patients. Genes involved in disease biology and having equal expression in both the subgroups, were further analysed for mutations and CNV using droplet digital PCR. TCRγδ+T-ALL patients exhibited differential level of mutations for NOTCH1 and IKZF3; however BRAF mutations were detected at equal levels in both the subgroups. Although TCRγδ+T-ALL patients with these mutations demonstrated improved disease-free survival (DFS) as compared TCRαβ+T-ALL patients, it was not statistically significant. Patients with homozygous deletion of CDKN2A/CDKN2B showed poor DFS in each subgroup. TCRγδ+T-ALL patients with wild type/heterozygous deletion of CDKN2A/CDKN2B possess significantly better DFS over TCRαβ+T-ALL patients (p=0.017 and 0.045, respectively). Thus, the present study has for the first time demonstrated TCRγδ clonality and CDKN2A/CDKN2B CNV together as potential prognostic markers in management of T-ALL. Further understanding the functional significance of differentially regulated genes in T-ALL patients would aid in designing risk based treatment strategies in subset specific manner.

Characterization of leukemias with ETV6-ABL1 fusion

To characterize the incidence, clinical features and genetics of ETV6-ABL1 leukemias, representing targetable kinase-activating lesions, we analyzed 44 new and published cases of ETV6-ABL1-positive hematologic malignancies [22 cases of acute lymphoblastic leukemia (13 children, 9 adults) and 22 myeloid malignancies (18 myeloproliferative neoplasms, 4 acute myeloid leukemias)]. The presence of the ETV6-ABL1 fusion was ascertained by cytogenetics, fluorescence in-situ hybridization, reverse transcriptase-polymerase chain reaction and RNA sequencing. Genomic and gene expression profiling was performed by single nucleotide polymorphism and expression arrays. Systematic screening of more than 4,500 cases revealed that in acute lymphoblastic leukemia ETV6-ABL1 is rare in childhood (0.17% cases) and slightly more common in adults (0.38%). There is no systematic screening of myeloproliferative neoplasms; however, the number of ETV6-ABL1-positive cases and the relative incidence of acute lymphoblastic leukemia and myeloproliferative neoplasms suggest that in adulthood ETV6-ABL1 is more common in BCR-ABL1-negative chronic myeloid leukemia-like myeloproliferations than in acute lymphoblastic leukemia. The genomic profile of ETV6-ABL1 acute lymphoblastic leukemia resembled that of BCR-ABL1 and BCR-ABL1-like cases with 80% of patients having concurrent CDKN2A/B and IKZF1 deletions. In the gene expression profiling all the ETV6-ABL1-positive samples clustered in close vicinity to BCR-ABL1 cases. All but one of the cases of ETV6-ABL1 acute lymphoblastic leukemia were classified as BCR-ABL1-like by a standardized assay. Over 60% of patients died, irrespectively of the disease or age subgroup examined. In conclusion, ETV6-ABL1 fusion occurs in both lymphoid and myeloid leukemias; the genomic profile and clinical behavior resemble BCR-ABL1-positive malignancies, including the unfavorable prognosis, particularly of acute leukemias. The poor outcome suggests that treatment with tyrosine kinase inhibitors should be considered for patients with this fusion.

Cell-Cycle Gene Alterations in 4,864 Tumors Analyzed by Next-Generation Sequencing: Implications for Targeted Therapeutics

Alterations in the cyclin-dependent kinase (CDK)-retinoblastoma (RB) machinery disrupt cell-cycle regulation and are being targeted in drug development. To understand the cancer types impacted by this pathway, we analyzed frequency of abnormalities in key cell-cycle genes across 4,864 tumors using next-generation sequencing (182 or 236 genes; Clinical Laboratory Improvement Amendments laboratory). Aberrations in the cell-cycle pathway were identified in 39% of cancers, making this pathway one of the most commonly altered in cancer. The frequency of aberrations was as follows: CDKN2A/B (20.1% of all patients), RB1 (7.6%), CCND1 (6.1%), CCNE1 (3.6%), CDK4 (3.2%), CCND3 (1.8%), CCND2 (1.7%), and CDK6 (1.7%). Rates and types of aberrant cell-cycle pathway genes differed between cancer types and within histologies. Analysis of coexisting and mutually exclusive genetic aberrations showed that CCND1, CCND2, and CCND3 aberrations were all positively associated with CDK6 aberrations [OR and P values, multivariate analysis: CCND1 and CDK6 (OR = 3.5; P < 0.0001), CCND2 and CDK6 (OR = 4.3; P = 0.003), CCND3 and CDK6 (OR = 3.6; P = 0.007)]. In contrast, RB1 alterations were negatively associated with multiple gene anomalies in the cell-cycle pathway, including CCND1 (OR = 0.25; P = 0.003), CKD4 (OR = 0.10; P = 0.001), and CDKN2A/B (OR = 0.21; P < 0.0001). In conclusion, aberrations in the cell-cycle pathway were very common in diverse cancers (39% of 4,864 neoplasms). The frequencies and types of alterations differed between and within tumor types and will be informative for drug development strategies. Mol Cancer Ther; 15(7); 1682-90. ©2016 AACR.

Correlation between deletion of the CDKN2 gene and tyrosine kinase inhibitor resistance in adult Philadelphia chromosome-positive acute lymphoblastic leukemia

BACKGROUND

Frequency relapses are common in Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) following tyrosine kinase inhibitors (TKIs). CDKN2A/B is believed to contribute to this chemotherapy resistance.

METHODS

To further investigate the association between CDKN2 status and TKI resistance, the prevalence of CDKN2 deletions and its correlation with a variety of clinical features was assessed in 135 Ph-positive ALL patients using interphase fluorescence in situ hybridization (I-FISH).

RESULTS

Results showed that no difference occurred between patients with CDKN2 deletion (44/135) and wild-type patients in sex, age, and complete remission (CR) rate following induction chemotherapy combined with tyrosine kinase inhibitors (TKIs). However, CDKN2 deletion carriers demonstrated higher white blood cell (WBC) count, enhanced rates of hepatosplenomegaly (P = 0.006), and upregulation of CD20 expression (P = 0.001). Moreover, deletions of CDKN2 resulted in lower rates of complete molecular response (undetectable BCR/ABL), increased cumulative incidence of relapse, short overall survival (OS), and disease-free survival (DFS) time (P < 0.05) even though these patients received chemotherapy plus TKIs followed by allogenic hematopoietic stem cell transplantation (Allo-HSCT). In the case of 44 patients who presented with CDKN2 deletion, 18 patients were treated with dasatinib treatment, and another 26 patients were treated with imatinib therapy, and our study found that there were no differences associated with OS (P = 0.508) and DFS (P = 0.555) between the two groups.

CONCLUSIONS

CDKN2 deletion is frequently acquired during Ph-positive ALL progression and serves as a poor prognostic marker of long-term outcome in Ph-positive ALL patients with CDKN2 deletion even after the second-generation tyrosine kinase inhibitor treatment.