Among patients with triple-negative breast cancer and high expression of PD-L1, pembrolizumab plus chemotherapy resulted in longer overall survival than chemotherapy alone.
Techniques for analyzing circulating tumor DNA (ctDNA) to detect, characterize and monitor cancer have matured rapidly. An increasing body of clinical evidence is demonstrating the capabilities of ...this technology as a diagnostic test. The full potential of ctDNA liquid biopsy in the diagnosis, characterization and management of solid and hematological malignancies will be uncovered through interventional clinical trials evaluating clinical utility. In this Review, we discuss the current landscape of ctDNA liquid-biopsy applications across the cancer continuum and highlight opportunities for clinical investigation.
Genomic sequencing studies of breast and other cancers have identified patterns of mutations that have been attributed to the endogenous mutator activity of APOBEC3B (A3B), a member of the AID/APOBEC ...family of cytidine deaminases. A3B gene expression is increased in many cancers, but its upstream drivers remain undefined. Furthermore, there exists a common germ-line deletion polymorphism ( A3B ᵈᵉˡ), which has been associated with a paradoxical increase in breast cancer risk. To examine causes and consequences of A3B expression and its constitutive absence in breast cancer, we analyzed two large clinically annotated genomic datasets The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). We confirmed that A3B expression is associated with aggressive clinicopathologic characteristics and adverse outcomes and show that A3B expression is highly correlated with proliferative features (mitosis and cell cycle-related gene expression) in breast and 15 of 16 other solid tumor types. However, breast cancers arising in homozygous A3B ᵈᵉˡ individuals with A3B absent did not differ in these features, indicating that A3B expression is a reflection rather than a direct cause of increased proliferation. Using gene set enrichment analysis (GSEA), we detected a pattern of immune activation in A3B ᵈᵉˡ breast cancers, which seems to be related to hypermutation arising in A3B ᵈᵉˡ carriers. Together, these results provide an explanation for A3B overexpression and its prognostic effect, giving context to additional study of this mutator as a cancer biomarker or putative drug target. In addition, although immune features of A3B ᵈᵉˡ require additional study, these findings nominate the A3B ᵈᵉˡ polymorphism as a potential predictor for cancer immunotherapy.
Significance Somatic mutagenesis is fundamental to the development and evolution of cancers. APOBEC3B (A3B) is a cellular deaminase, which is overexpressed in cancers and believed to be an important cause of cancer-associated mutations. The factors responsible for A3B up-regulation are unknown. Interestingly, a germ-line deletion polymorphism exists, such that a significant proportion of the global population does not express A3B protein. Using large human cancer datasets, we show that A3B expression is strongly associated with cellular proliferation. Furthermore, we identify a pattern of immune activation related to hypermutation in tumors arising in A3B deletion carriers suggesting that these patients could respond differently to immune-directed therapies. These results provide important context for the ongoing study of A3B as a therapeutic target or biomarker.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
PLK4 was identified as a promising therapeutic target through a systematic approach that combined RNAi screening with gene expression analysis in human breast cancers and cell lines. A drug discovery ...program culminated in CFI-400945, a potent and selective PLK4 inhibitor. Cancer cells treated with CFI-400945 exhibit effects consistent with PLK4 kinase inhibition, including dysregulated centriole duplication, mitotic defects, and cell death. Oral administration of CFI-400945 to mice bearing human cancer xenografts results in the significant inhibition of tumor growth at doses that are well tolerated. Increased antitumor activity in vivo was observed in PTEN-deficient compared to PTEN wild-type cancer xenografts. Our findings provide a rationale for the clinical evaluation of CFI-400945 in patients with solid tumors, in particular those deficient in PTEN.
•CFI-400945 is a PLK4 small molecule inhibitor with significant anticancer activity•CFI-400945 causes dysregulated centriole duplication, mitotic errors, and cell death•CFI-400945 may represent a therapeutic option for a range of solid tumors
Mason et al. show that PLK4 is a potential therapeutic target in human cancers. Mason et al. further identify a PLK4 inhibitor, CFI-400945, and demonstrate its potential as a clinically useful cancer therapeutic.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Controversy over the role of antioxidants in cancer has persisted for decades. Here, we demonstrate that synthesis of the antioxidant glutathione (GSH), driven by GCLM, is required for cancer ...initiation. Genetic loss of Gclm prevents a tumor’s ability to drive malignant transformation. Intriguingly, these findings can be replicated using an inhibitor of GSH synthesis, but only if delivered prior to cancer onset, suggesting that at later stages of tumor progression GSH becomes dispensable potentially due to compensation from alternative antioxidant pathways. Remarkably, combined inhibition of GSH and thioredoxin antioxidant pathways leads to a synergistic cancer cell death in vitro and in vivo, demonstrating the importance of these two antioxidants to tumor progression and as potential targets for therapeutic intervention.
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•The GSH antioxidant pathway is required for cancer initiation•After cancer initiation, GSH is dispensable due to alternative antioxidant pathways•The TXN antioxidant pathway is upregulated in tumors•Inhibition of both GSH and TXN pathways causes synergistic cancer cell death
Harris et al. show that the antioxidant glutathione (GSH) is required for cancer initiation but not for established tumors partly due to upregulation of the thioredoxin (TXN) antioxidant pathway in the latter. Consequently, blocking both GSH and TXN pathways synergistically inhibits tumor growth.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A number of randomized controlled trials (RCTs) have reported improvement in breast cancer outcomes from extending treatment with aromatase inhibitors (AIs) beyond the initial five years after ...diagnosis. However, the toxicity profile of extended AIs is uncertain.
We identified RCTs that compared extended AIs to placebo or no treatment using MEDLINE and a review of abstracts from key conferences between 2013 and 2016. Odds ratios (ORs), 95% confidence intervals (CIs), absolute risks, and the number needed to harm (NNH) were computed for prespecified safety and tolerability outcomes including cardiovascular events, bone fractures, second cancers (excluding new breast cancer), treatment discontinuation for adverse events, and death without recurrence. All statistical tests were two-sided.
Seven trials comprising 16 349 patients met the inclusion criteria. Longer treatment with AIs was associated with increased odds of cardiovascular events (OR = 1.18, 95% CI = 1.00 to 1.40, P = .05, NNH = 122), bone fractures (OR = 1.34, 95% CI = 1.16 to 1.55, P < .001, NNH = 72), and treatment discontinuation for adverse events (OR = 1.45, 95% CI = 1.25 to 1.68, P < .001, NNH = 21). Longer treatment with AIs did not influence the odds of either second malignancy (OR = 0.93, 95% CI = 0.73 to 1.18, P = .56) or deaths without breast cancer recurrence (OR = 1.11, 95% CI = 0.90 to 1.36, P = .34).
Extended treatment with AIs is associated with an increased risk of cardiovascular events and bone fractures. There is no statistically significant increase in deaths without breast cancer recurrence among patients receiving longer treatment with AIs. These data should be taken into account when considering extended adjuvant AIs.
Estrogen receptor (ER+) breast cancer is the most frequently diagnosed breast cancer subtype. Currently, adjuvant treatment for early stage disease consists of endocrine therapy, with or without ...chemotherapy and bone-targeted therapy, delivered in a risk-adapted manner. Despite this multimodal approach, a significant proportion of high risk patients will develop incurable distant recurrences. There is an ongoing need to develop new treatment strategies that address the biologic causes of treatment failure and to identify the individual patients who can benefit from such interventions. Here we review the clinical investigation of targeted and novel therapies, including inhibitors of the PI3K-AKT-mTOR pathway, oral selective estrogen receptor degraders (SERDs), and PARP-inhibitors for the treatment of early ER+ breast cancer. Furthermore, we highlight opportunities in biomarker development to help guide the delivery of escalated adjuvant strategies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Given the low response rates observed in the overall population with pretreated triple-negative breast cancer in previous studies of anti-PD-1 or anti-PD-L1 monotherapy,2,5 the primary results of ...KEYNOTE-119 are unsurprising. Since KEYNOTE-119 was launched, clinical development has focused principally on combinations of chemotherapy and immunotherapy in the first-line setting. The finding that this higher PD-L1 expression threshold might be a predictor of pembrolizumab monotherapy benefit adds to previously observed associations with single drug immunotherapy benefit, including de-novo metastatic disease, absence of previous chemotherapy, normal lactate dehydrogenase, lung or nodal involvement, and absence of liver metastases.2 The hypothesis that checkpoint inhibitor monotherapy is active at higher concentrations of PD-L1 expression, and that at lower concentrations, combination chemoimmunotherapy is required, is analogous to findings in non-small-cell lung cancer. DWC reports consultancy and advisory fees from Agendia, AstraZeneca, Dynamo Therapeutics, Exact Sciences, GlaxoSmithKline, Merck, Novartis, Pfizer, Puma Biotechnology, and Roche; research funding to their institution from GlaxoSmithKline, Pfizer, and Roche; is a member of a trial steering committee for Merck; and holds a holds a patent (US62/675,228) for methods of treating cancers characterized by a high expression level of spindle and kinetochore associated complex subunit 3 (ska3) gene.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Patient-derived tumor organoids (PDOs) are a highly promising preclinical model that recapitulates the histology, gene expression, and drug response of the donor patient tumor. Currently, PDO culture ...relies on basement-membrane extract (BME), which suffers from batch-to-batch variability, the presence of xenogeneic compounds and residual growth factors, and poor control of mechanical properties. Additionally, for the development of new organoid lines from patient-derived xenografts, contamination of murine host cells poses a problem. We propose a nanofibrillar hydrogel (EKGel) for the initiation and growth of breast cancer PDOs. PDOs grown in EKGel have histopathologic features, gene expression, and drug response that are similar to those of their parental tumors and PDOs in BME. In addition, EKGel offers reduced batch-to-batch variability, a range of mechanical properties, and suppressed contamination from murine cells. These results show that EKGel is an improved alternative to BME matrices for the initiation, growth, and maintenance of breast cancer PDOs.
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