Centre for Cancer Research - Research Publications
Now showing items 1-12 of 107
Analytical demands to use whole-genome sequencing in precision oncology.
(Elsevier BV, 2021-06-10)
Interrogating the tumor genome in its entirety by whole-genome sequencing (WGS) offers an unprecedented insight into the biology and pathogenesis of cancer, with potential impact on diagnostics, prognostication and therapy selection. WGS is able to detect sequence as well as structural variants and thereby combines central domains of cytogenetics and molecular genetics. Given the potential of WGS in directing targeted therapeutics and clinical decision-making, we envision a gradual transition of the method from research to clinical routine. This review is one out of three within this issue aimed at facilitating this effort, by discussing in-depth analytical validation, clinical interpretation and clinical utility of WGS. The review highlights the requirements for implementing, validating and maintaining a clinical WGS pipeline to obtain high-quality patient-specific data in accordance with the local regulatory landscape. Every step of the WGS pipeline, which includes DNA extraction, library preparation, sequencing, bioinformatics analysis, and data storage, is considered with respect to its logistics, necessities, potential pitfalls, and the required quality management. WGS is likely to drive clinical diagnostics and patient care forward, if requirements and challenges of the technique are recognized and met.
Targeting the undruggable in pancreatic cancer using nano-based gene silencing drugs.
(Elsevier BV, 2020-05)
Pancreatic cancer is predicted to be the second leading cause of cancer-related death by 2025. The best chemotherapy only extends survival by an average of 18 weeks. The extensive fibrotic stroma surrounding the tumor curbs therapeutic options as chemotherapy drugs cannot freely penetrate the tumor. RNA interference (RNAi) has emerged as a promising approach to revolutionize cancer treatment. Small interfering RNA (siRNA) can be designed to inhibit the expression of any gene which is important given the high degree of genetic heterogeneity present in pancreatic tumors. Despite the potential of siRNA therapies, there are hurdles limiting their clinical application such as poor transport across biological barriers, limited cellular uptake, degradation, and rapid clearance. Nanotechnology can address these challenges. In fact, the past few decades have seen the conceptualization, design, pre-clinical testing and recent clinical approval of a RNAi nanodrug to treat disease. In this review, we comment on the current state of play of clinical trials evaluating siRNA nanodrugs and review pre-clinical studies investigating the efficacy of siRNA therapeutics in pancreatic cancer. We assess the physiological barriers unique to pancreatic cancer that need to be considered when designing and testing new nanomedicines for this disease.
Changes in Opioid Prescribing Patterns Among Generalists and Oncologists for Medicare Part D Beneficiaries From 2013 to 2017.
(American Medical Association (AMA), 2020-08-01)
Importance: In response to the opioid epidemic, policies aiming to reduce opioid prescribing, misuse, and abuse may have the unintended consequence of restricting access to necessary opioid therapy for cancer-related pain. It is unknown how opioid prescribing patterns have changed among generalists and oncologists during this era. Objective: To examine trends in opioid prescription rates for Medicare Part D beneficiaries from 2013 to 2017 among oncologists and generalists. Design, Setting, and Participants: This repeated cross-sectional study of generalist physicians (internal medicine, family medicine, geriatric medicine, general practice) and oncology specialists (medical oncology, hematology-oncology, and radiation oncology) analyzed the Medicare Provider Utilization and Payment Data: Part D prescriber files from 2013 to 2017. Exposures: Generalist vs oncology specialty. Main Outcomes and Measures: Outcomes included physician-level rates of both opioid and long-acting opioid prescriptions per 100 Medicare Part D beneficiaries. Poisson regression was used to estimate annual predicted outcome rates and incidence rate ratios, adjusting for prescriber characteristics and state fixed effects. Results: We analyzed the prescribing patterns of 251 820 generalists and 14 210 oncologists. From 2013 to 2017, the annual adjusted predicted mean rate of opioid prescriptions per 100 Medicare beneficiaries decreased from 68.2 to 49.7 among generalists (adjusted incidence rate ratio [aIRR] = 0.73; 95% CI, 0.73-0.73) and from 77.8 to 58.8 among oncologists (aIRR = 0.76; 95% CI, 0.74-0.77). The rate of long-acting opioid prescriptions per 100 Medicare beneficiaries also decreased from 8.0 to 5.4 for generalists (aIRR = 0.67; 95% CI, 0.66-0.68) and from 18.6 to 13.3 for oncologists (aIRR = 0.72; 95% CI, 0.69-0.74). Conclusions and Relevance: We found large declines in opioid prescription rates for Medicare beneficiaries by generalists and oncologists from 2013 to 2017. Opioid policy and advocacy appear to have been effective in reducing the extent of opioid prescribing in the Medicare population. Similar declines between generalists and oncologists raise concern that access to cancer pain management may have been inadvertently restricted. How much of the decrease in prescribing by oncologists is appropriate vs inappropriate deserves further investigation.
Intact TP-53 function is essential for sustaining durable responses to BH3-mimetic drugs in leukemias
(AMER SOC HEMATOLOGY, 2021-05-20)
Selective targeting of BCL-2 with the BH3-mimetic venetoclax has been a transformative treatment for patients with various leukemias. TP-53 controls apoptosis upstream of where BCL-2 and its prosurvival relatives, such as MCL-1, act. Therefore, targeting these prosurvival proteins could trigger apoptosis across diverse blood cancers, irrespective of TP53 mutation status. Indeed, targeting BCL-2 has produced clinically relevant responses in blood cancers with aberrant TP-53. However, in our study, TP53-mutated or -deficient myeloid and lymphoid leukemias outcompeted isogenic controls with intact TP-53, unless sufficient concentrations of BH3-mimetics targeting BCL-2 or MCL-1 were applied. Strikingly, tumor cells with TP-53 dysfunction escaped and thrived over time if inhibition of BCL-2 or MCL-1 was sublethal, in part because of an increased threshold for BAX/BAK activation in these cells. Our study revealed the key role of TP-53 in shaping long-term responses to BH3-mimetic drugs and reconciled the disparate pattern of initial clinical response to venetoclax, followed by subsequent treatment failure among patients with TP53-mutant chronic lymphocytic leukemia or acute myeloid leukemia. In contrast to BH3-mimetics targeting just BCL-2 or MCL-1 at doses that are individually sublethal, a combined BH3-mimetic approach targeting both prosurvival proteins enhanced lethality and durably suppressed the leukemia burden, regardless of TP53 mutation status. Our findings highlight the importance of using sufficiently lethal treatment strategies to maximize outcomes of patients with TP53-mutant disease. In addition, our findings caution against use of sublethal BH3-mimetic drug regimens that may enhance the risk of disease progression driven by emergent TP53-mutant clones.
Association of Current Opioid Use With Serious Adverse Events Among Older Adult Survivors of Breast Cancer.
(American Medical Association (AMA), 2020-09-01)
Importance: National efforts to improve safe opioid prescribing focus on preventing misuse, overdose, and opioid use disorder. This approach overlooks opportunities to better prevent other serious opioid-related harms in complex populations, such as older adult survivors of cancer. Little is known about the rates and risk factors for comprehensive opioid-related harms in this population. Objective: To determine rates of multiple opioid-related adverse drug events among older adults who survived breast cancer and estimate the risk of these events associated with opioid use in the year after completing cancer treatment. Design, Setting, and Participants: This retrospective cohort study used 2007 to 2016 Surveillance, Epidemiology and End Results-Medicare data from fee-for-service Medicare beneficiaries with first cancer diagnosis of stage 0 to III breast cancer at age 66 to 90 years from January 1, 2008, through December 31, 2015, who completed active breast cancer treatment. Data were analyzed from October 31, 2019, to June 10, 2020. Exposures: Repeated daily measure indicating possession of any prescription opioid supply in Medicare Part D prescription claims. Main Outcomes and Measures: Adjusted risk ratios (aRRs), estimated using modified Poisson generalized estimating equation models, for adverse drug events related to substance misuse (ie, diagnosed opioid abuse, dependence, or poisoning), other adverse drug events associated with opioid use (ie, gastrointestinal events, infections, falls and fractures, or cardiovascular events), and all-cause hospitalization associated with opioid supply the prior day, controlling for patient characteristics. Results: Among 38 310 women included in the study (mean [SD] age, 74.3 [6.3] years), there were 0.010 (95% CI, 0.008-0.011) adverse drug events related to substance misuse per 1000 person-days, 0.237 (95% CI, 0.229-0.245) other adverse drug events associated with opioid use per 1000 person-days, and 0.675 (95% CI, 0.662-0.689) all-cause hospitalizations per 1000 person-days. Opioid use was associated with increased risk of adverse drug events related to substance misuse (aRR, 14.62; 95% CI, 9.69-22.05; P < .001), other adverse drug events related to opioid use (aRR, 2.50; 95% CI, 2.11-2.96; P < .001), and all-cause hospitalization (aRR, 2.77; 95% CI, 2.55-3.02; P < .001). In a dose-response effect, individuals with high daily opioid doses had consistently higher risks of all study outcomes compared with individuals who had low opioid doses. Compared with days with no opioid exposure, the risk of any adverse drug event related to substance misuse was 3.4-fold higher for individuals with a current opioid supply ≥50 mg morphine equivalent dose per day (aRR, 3.40; 95% CI, 2.47-4.68; P < .001), while the risk was 2.3-fold higher for individuals with 1 to 49 mg morphine equivalent dose per day (aRR, 2.29; 95% CI, 1.89-2.77; P < .001). Conclusions and Relevance: These findings suggest that among older adults who survived breast cancer, continued prescription opioid use in the year after completing active cancer treatment was associated with an immediate increased risk of a broad range of serious adverse drug events related to substance misuse and other adverse drug events associated with opioid use. Clinicians should consider the comprehensive risks of managing cancer pain with long-term opioid therapy.
Medicaid prescription limits and their implications for naloxone accessibility.
(Elsevier BV, 2021-01-01)
BACKGROUND: Expanding access to and utilization of naloxone is a vitally important harm reduction strategy for preventing opioid overdose deaths, particularly in vulnerable populations like Medicaid beneficiaries. The objective of this study was to characterize the landscape of monthly prescription fill limit policies in Medicaid programs and their potential implications for expanding naloxone use for opioid overdose harm reduction. METHODS: A cross-sectional, multi-modal online and telephonic data collection strategy was used to identify and describe the presence and characteristics of monthly prescription fill limit policies across state Medicaid programs. Contextual characteristics were described regarding each state's Medicaid enrollment, opioid prescribing rates, and overdose death rates. Data collection and analysis occurred between February and May 2020. RESULTS: Medicaid-covered naloxone fills are currently subject to monthly prescription fill limit policies in 10 state Medicaid programs, which cover 20 % of the Medicaid population nationwide. Seven of these programs are located in states ranking in the top 10 highest per-capita opioid prescribing rates in the country. However, 8 of these programs are located in states with opioid overdose death rates below the national average. CONCLUSIONS: Medicaid beneficiaries at high risk of opioid overdose living in states with monthly prescription fill limits may experience significant barriers to obtaining naloxone. Exempting naloxone from Medicaid prescription limit restrictions may help spur broader adoption of naloxone for opioid overdose mortality prevention, especially in states with high opioid prescribing rates. Achieving unfettered naloxone coverage in Medicaid is critical as opioid overdoses and Medicaid enrollment increase amid the COVID-19 pandemic.
Targeting DNA Damage Response and Replication Stress in Pancreatic Cancer
(W B SAUNDERS CO-ELSEVIER INC, 2021-01-01)
BACKGROUND & AIMS: Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress, and novel therapeutic response in PC to develop a biomarker-driven therapeutic strategy targeting DDR and replication stress in PC. METHODS: We interrogated the transcriptome, genome, proteome, and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient-derived xenografts and human PC organoids. RESULTS: Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors, including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, cosegregates with response to platinum (P < .001) and PARP inhibitor therapy (P < .001) in vitro and in vivo. We generated a novel signature of replication stress that predicts response to ATR (P < .018) and WEE1 inhibitor (P < .029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P < .001) but was not associated with DDR deficiency. CONCLUSIONS: Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR-proficient PC and after platinum therapy.
Immune recovery in patients with mantle cell lymphoma receiving long-term ibrutinib and venetoclax combination therapy
(AMER SOC HEMATOLOGY, 2020-10-13)
Combination venetoclax plus ibrutinib for the treatment of mantle cell lymphoma (MCL) has demonstrated efficacy in the relapsed or refractory setting; however, the long-term impact on patient immunology is unknown. In this study, changes in immune subsets of MCL patients treated with combination venetoclax and ibrutinib were assessed over a 4-year period. Multiparameter flow cytometry of peripheral blood mononuclear cells showed that ≥12 months of treatment resulted in alterations in the proportions of multiple immune subsets, most notably CD4+ and CD8+ effector and central memory T cells and natural killer cells, and normalization of T-cell cytokine production in response to T-cell receptor stimulation. Gene expression analysis identified upregulation of multiple myeloid genes (including S100 and cathepsin family members) and inflammatory pathways over 12 months. Four patients with deep responses stopped study drugs, resulting in restoration of normal immune subsets for all study parameters except myeloid gene/pathway expression, suggesting long-term combination venetoclax and ibrutinib irreversibly affects this population. Our findings demonstrate that long-term combination therapy is associated with immune recovery in MCL, which may allow responses to subsequent immunotherapies and suggests that this targeted therapy results in beneficial impacts on immunological recovery. This trial was registered at www.clinicaltrials.gov as #NCT02471391.
DNA methylation patterns identify subgroups of pancreatic neuroendocrine tumors with clinical association
(NATURE RESEARCH, 2021-02-03)
Here we report the DNA methylation profile of 84 sporadic pancreatic neuroendocrine tumors (PanNETs) with associated clinical and genomic information. We identified three subgroups of PanNETs, termed T1, T2 and T3, with distinct patterns of methylation. The T1 subgroup was enriched for functional tumors and ATRX, DAXX and MEN1 wild-type genotypes. The T2 subgroup contained tumors with mutations in ATRX, DAXX and MEN1 and recurrent patterns of chromosomal losses in half of the genome with no association between regions with recurrent loss and methylation levels. T2 tumors were larger and had lower methylation in the MGMT gene body, which showed positive correlation with gene expression. The T3 subgroup harboured mutations in MEN1 with recurrent loss of chromosome 11, was enriched for grade G1 tumors and showed histological parameters associated with better prognosis. Our results suggest a role for methylation in both driving tumorigenesis and potentially stratifying prognosis in PanNETs.
Recurrent loss of heterozygosity correlates with clinical outcome in pancreatic neuroendocrine cancer
Pancreatic neuroendocrine tumors (pNETs) are uncommon cancers arising from pancreatic islet cells. Here we report the analysis of gene mutation, copy number, and RNA expression of 57 sporadic well-differentiated pNETs. pNET genomes are dominated by aneuploidy, leading to concordant changes in RNA expression at the level of whole chromosomes and chromosome segments. We observed two distinct patterns of somatic pNET aneuploidy that are associated with tumor pathology and patient prognosis. Approximately 26% of the patients in this series had pNETs with genomes characterized by recurrent loss of heterozygosity (LoH) of 10 specific chromosomes, accompanied by bi-allelic MEN1 inactivation and generally poor clinical outcome. Another ~40% of patients had pNETs that lacked this recurrent LoH pattern but had chromosome 11 LoH, bi-allelic MEN1 inactivation, and universally good clinical outcome. The somatic aneuploidy allowed pathogenic germline variants (e.g., ATM) to be expressed unopposed, with RNA expression patterns showing inactivation of downstream tumor suppressor pathways. No prognostic associations were found with tumor morphology, single gene mutation, or expression of RNAs reflecting the activity of immune, differentiation, proliferative or tumor suppressor pathways. In pNETs, single gene mutations appear to be less important than aneuploidy, with MEN1 the only statistically significant recurrently mutated driver gene. In addition, only one pNET in the series had clearly actionable single nucleotide variants (SNVs) (in PTEN and FLCN) confirmed by corroborating RNA expression changes. The two clinically relevant patterns of LoH described here define a novel oncogenic mechanism and a plausible route to genomic precision oncology for this tumor type.