Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
28 result(s) for "Shah, Ronak H."
Sort by:
Genomic and transcriptomic hallmarks of poorly differentiated and anaplastic thyroid cancers
Poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) are rare and frequently lethal tumors that so far have not been subjected to comprehensive genetic characterization. We performed next-generation sequencing of 341 cancer genes from 117 patient-derived PDTCs and ATCs and analyzed the transcriptome of a representative subset of 37 tumors. Results were analyzed in the context of The Cancer Genome Atlas study (TCGA study) of papillary thyroid cancers (PTC). Compared to PDTCs, ATCs had a greater mutation burden, including a higher frequency of mutations in TP53, TERT promoter, PI3K/AKT/mTOR pathway effectors, SWI/SNF subunits, and histone methyltransferases. BRAF and RAS were the predominant drivers and dictated distinct tropism for nodal versus distant metastases in PDTC. RAS and BRAF sharply distinguished between PDTCs defined by the Turin (PDTC-Turin) versus MSKCC (PDTC-MSK) criteria, respectively. Mutations of EIF1AX, a component of the translational preinitiation complex, were markedly enriched in PDTCs and ATCs and had a striking pattern of co-occurrence with RAS mutations. While TERT promoter mutations were rare and subclonal in PTCs, they were clonal and highly prevalent in advanced cancers. Application of the TCGA-derived BRAF-RAS score (a measure of MAPK transcriptional output) revealed a preserved relationship with BRAF/RAS mutation in PDTCs, whereas ATCs were BRAF-like irrespective of driver mutation. These data support a model of tumorigenesis whereby PDTCs and ATCs arise from well-differentiated tumors through the accumulation of key additional genetic abnormalities, many of which have prognostic and possible therapeutic relevance. The widespread genomic disruptions in ATC compared with PDTC underscore their greater virulence and higher mortality. This work was supported in part by NIH grants CA50706, CA72597, P50-CA72012, P30-CA008748, and 5T32-CA160001; the Lefkovsky Family Foundation; the Society of Memorial Sloan Kettering; the Byrne fund; and Cycle for Survival.
Antitumour activity of neratinib in patients with HER2-mutant advanced biliary tract cancers
HER2 mutations are infrequent genomic events in biliary tract cancers (BTCs). Neratinib, an irreversible, pan-HER, oral tyrosine kinase inhibitor, interferes with constitutive receptor kinase activation and has activity in HER2 -mutant tumours. SUMMIT is an open-label, single-arm, multi-cohort, phase 2, ‘basket’ trial of neratinib in patients with solid tumours harbouring oncogenic HER2 somatic mutations (ClinicalTrials.gov: NCT01953926). The primary objective of the BTC cohort, which is now complete, is first objective response rate (ORR) to neratinib 240 mg orally daily. Secondary objectives include confirmed ORR, clinical benefit rate, progression-free survival, duration of response, overall survival, safety and tolerability. Genomic analyses were exploratory. Among 25 treatment-refractory patients (11 cholangiocarcinoma, 10 gallbladder, 4 ampullary cancers), the ORR is 16% (95% CI 4.5–36.1%). The most common HER2 mutations are S310F (n = 11; 48%) and V777L (n = 4; 17%). Outcomes appear worse for ampullary tumours or those with co-occurring oncogenic TP53 and CDKN2A alterations. Loss of amplified HER2 S310F and acquisition of multiple previously undetected oncogenic co-mutations are identified at progression in one responder. Diarrhoea is the most common adverse event, with any-grade diarrhoea in 14 patients (56%). Although neratinib demonstrates antitumour activity in patients with refractory BTC harbouring HER2 mutations, the primary endpoint was not met and combinations may be explored. In biliary tract cancer HER2 alterations correlate with poor prognosis. Here, the authors present the results of a phase II clinical trial reporting the efficacy and safety of the tyrosine kinase inhibitor neratinib in patients with HER2-mutation positive advanced biliary tract cancers.
Alternative transcription initiation leads to expression of a novel ALK isoform in cancer
A novel ALK transcript expressed in a subset of human cancers, arising from a de novo alternative transcription initiation site within the ALK gene, is described; the ALK transcript encodes three protein isoforms that stimulate tumorigenesis in vivo in mouse models; resultant tumours are sensitive to treatments with ALK inhibitors, indicating a possible therapeutic avenue for patients expressing these isoforms. A novel oncogene activation mechanism Oncogenes are usually activated by genetic abberations. Ping Chi and colleagues have identified a novel isoform of the anaplastic lymphoma kinase (ALK) in a subset of human cancers, arising independently of genomic aberrations at the ALK locus through alternative transcription initiation in ALK intron 19. Tumours driven by the transcript, termed ALK ATI , are sensitive to ALK inhibitors, suggesting ALK inhibitors as possible therapeutics in patients expressing these isoforms. Activation of oncogenes by mechanisms other than genetic aberrations such as mutations, translocations, or amplifications is largely undefined. Here we report a novel isoform of the anaplastic lymphoma kinase (ALK) that is expressed in ∼11% of melanomas and sporadically in other human cancer types, but not in normal tissues. The novel ALK transcript initiates from a de novo alternative transcription initiation (ATI) site in ALK intron 19, and was termed ALK ATI . In ALK ATI -expressing tumours, the ATI site is enriched for H3K4me3 and RNA polymerase II, chromatin marks characteristic of active transcription initiation sites 1 . ALK ATI is expressed from both ALK alleles, and no recurrent genetic aberrations are found at the ALK locus, indicating that the transcriptional activation is independent of genetic aberrations at the ALK locus. The ALK ATI transcript encodes three proteins with molecular weights of 61.1, 60.8 and 58.7 kilodaltons, consisting primarily of the intracellular tyrosine kinase domain. ALK ATI stimulates multiple oncogenic signalling pathways, drives growth-factor-independent cell proliferation in vitro, and promotes tumorigenesis in vivo in mouse models. ALK inhibitors can suppress the kinase activity of ALK ATI , suggesting that patients with ALK ATI -expressing tumours may benefit from ALK inhibitors. Our findings suggest a novel mechanism of oncogene activation in cancer through de novo alternative transcription initiation.
Precision oncology: lessons learned and challenges for the future
The decreasing cost of and increasing capacity of DNA sequencing has led to vastly increased opportunities for population-level genomic studies to discover novel genomic alterations associated with both Mendelian and complex phenotypes. To translate genomic findings clinically, a number of health care institutions have worked collaboratively or individually to initiate precision medicine programs. These precision medicine programs involve designing patient enrollment systems, tracking electronic health records, building biobank repositories, and returning results with actionable matched therapies. As cancer is a paradigm for genetic diseases and new therapies are increasingly tailored to attack genetic susceptibilities in tumors, these precision medicine programs are largely driven by the urgent need to perform genetic profiling on cancer patients in real time. Here, we review the current landscape of precision oncology and highlight challenges to be overcome and examples of benefits to patients. Furthermore, we make suggestions to optimize future precision oncology programs based upon the lessons learned from these \"first generation\" early adopters. Keywords: next-generation sequencing, pathogenic variant, driver mutation, actionable mutation, cancer disparities
Tracking tumour evolution in glioma through liquid biopsies of cerebrospinal fluid
Diffuse gliomas are the most common malignant brain tumours in adults and include glioblastomas and World Health Organization (WHO) grade II and grade III tumours (sometimes referred to as lower-grade gliomas). Genetic tumour profiling is used to classify disease and guide therapy 1 , 2 , but involves brain surgery for tissue collection; repeated tumour biopsies may be necessary for accurate genotyping over the course of the disease 3 – 10 . While the detection of circulating tumour DNA (ctDNA) in the blood of patients with primary brain tumours remains challenging 11 , 12 , sequencing of ctDNA from the cerebrospinal fluid (CSF) may provide an alternative way to genotype gliomas with lower morbidity and cost 13 , 14 . We therefore evaluated the representation of the glioma genome in CSF from 85 patients with gliomas who underwent a lumbar puncture because they showed neurological signs or symptoms. Here we show that tumour-derived DNA was detected in CSF from 42 out of 85 patients (49.4%) and was associated with disease burden and adverse outcome. The genomic landscape of glioma in the CSF included a broad spectrum of genetic alterations and closely resembled the genomes of tumour biopsies. Alterations that occur early during tumorigenesis, such as co-deletion of chromosome arms 1p and 19q (1p/19q codeletion) and mutations in the metabolic genes isocitrate dehydrogenase 1 ( IDH1 ) or IDH2 1 , 2 , were shared in all matched ctDNA-positive CSF–tumour pairs, whereas growth factor receptor signalling pathways showed considerable evolution. The ability to monitor the evolution of the glioma genome through a minimally invasive technique could advance the clinical development and use of genotype-directed therapies for glioma, one of the most aggressive human cancers. Identification and sequencing of circulating tumour DNA in the cerebrospinal fluid of patients with glioma.
Ultrasensitive plasma-based monitoring of tumor burden using machine-learning-guided signal enrichment
In solid tumor oncology, circulating tumor DNA (ctDNA) is poised to transform care through accurate assessment of minimal residual disease (MRD) and therapeutic response monitoring. To overcome the sparsity of ctDNA fragments in low tumor fraction (TF) settings and increase MRD sensitivity, we previously leveraged genome-wide mutational integration through plasma whole-genome sequencing (WGS). Here we now introduce MRD-EDGE, a machine-learning-guided WGS ctDNA single-nucleotide variant (SNV) and copy-number variant (CNV) detection platform designed to increase signal enrichment. MRD-EDGE SNV uses deep learning and a ctDNA-specific feature space to increase SNV signal-to-noise enrichment in WGS by ~300× compared to previous WGS error suppression. MRD-EDGE CNV also reduces the degree of aneuploidy needed for ultrasensitive CNV detection through WGS from 1 Gb to 200 Mb, vastly expanding its applicability within solid tumors. We harness the improved performance to identify MRD following surgery in multiple cancer types, track changes in TF in response to neoadjuvant immunotherapy in lung cancer and demonstrate ctDNA shedding in precancerous colorectal adenomas. Finally, the radical signal-to-noise enrichment in MRD-EDGE SNV enables plasma-only (non-tumor-informed) disease monitoring in advanced melanoma and lung cancer, yielding clinically informative TF monitoring for patients on immune-checkpoint inhibition. Detection of circulating tumor DNA using MRD-EDGE, a machine-learning-guided single-nucleotide variant and copy-number variant detection platform for signal enrichment, enables monitoring of minimal residual disease and immunotherapy response in settings of low tumor burden.
Convergent loss of PTEN leads to clinical resistance to a PI(3)Kα inhibitor
A study of genome evolution in a metastatic breast cancer bearing an activating PIK3CA mutation, following treatment with the PI(3)Kα inhibitor BYL719, shows that all metastatic lesions, when compared to the pre-treatment tumour, had lost a copy of PTEN; parallel genetic evolution of separate sites with different PTEN genomic alterations had led to a convergent PTEN-null phenotype resistant to PI(3)Kα inhibition. Anticancer resistance due to PTEN loss The emergence and expansion of resistant clonal subpopulations is a major challenge facing the field of targeted therapeutics. Here, the authors study genome evolution in a metastatic breast cancer bearing an activating PIK3CA mutation, following treatment with the phosphatidylinositol-4,5-bisphosphate 3-kinase alpha subunit (PI(3)Kα) selective-inhibitor BYL719. Fourteen metastatic sites were sequenced to reveal that all metastatic lesions, when compared to the pre-treatment tumour, had lost a copy of the gene for the tumour suppressor phosphatase PTEN . Resistance to BYL719 was associated with additional and different PTEN genetic alterations, resulting in loss of PTEN expression. Based on these observations and additional functional characterization, the authors conclude that parallel genetic evolution of separate sites with different PTEN genomic alterations leads to a convergent PTEN-null phenotype resistant to PI(3)Kα inhibition. Broad and deep tumour genome sequencing has shed new light on tumour heterogeneity and provided important insights into the evolution of metastases arising from different clones 1 , 2 . There is an additional layer of complexity, in that tumour evolution may be influenced by selective pressure provided by therapy, in a similar fashion to that occurring in infectious diseases. Here we studied tumour genomic evolution in a patient (index patient) with metastatic breast cancer bearing an activating PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha, PI(3)Kα) mutation. The patient was treated with the PI(3)Kα inhibitor BYL719, which achieved a lasting clinical response, but the patient eventually became resistant to this drug (emergence of lung metastases) and died shortly thereafter. A rapid autopsy was performed and material from a total of 14 metastatic sites was collected and sequenced. All metastatic lesions, when compared to the pre-treatment tumour, had a copy loss of PTEN (phosphatase and tensin homolog) and those lesions that became refractory to BYL719 had additional and different PTEN genetic alterations, resulting in the loss of PTEN expression. To put these results in context, we examined six other patients also treated with BYL719. Acquired bi-allelic loss of PTEN was found in one of these patients, whereas in two others PIK3CA mutations present in the primary tumour were no longer detected at the time of progression. To characterize our findings functionally, we examined the effects of PTEN knockdown in several preclinical models (both in cell lines intrinsically sensitive to BYL719 and in PTEN -null xenografts derived from our index patient), which we found resulted in resistance to BYL719, whereas simultaneous PI(3)K p110β blockade reverted this resistance phenotype. We conclude that parallel genetic evolution of separate metastatic sites with different PTEN genomic alterations leads to a convergent PTEN-null phenotype resistant to PI(3)Kα inhibition.
First-line regorafenib with nivolumab and chemotherapy in advanced oesophageal, gastric, or gastro-oesophageal junction cancer in the USA: a single-arm, single-centre, phase 2 trial
The addition of nivolumab to chemotherapy improves survival in patients with advanced oesophagogastric (oesophageal, gastric, or gastro-oesophageal junction) adenocarcinoma; however, outcomes remain poor. We assessed the safety and activity of regorafenib in combination with nivolumab and chemotherapy in the first-line treatment of advanced oesophagogastric adenocarcinoma. This investigator-initiated, single-arm, phase 2 trial in adult patients (aged ≥18 years) with previously untreated, HER2-negative, metastatic oesophagogastric adenocarcinoma was done at the Memorial Sloan Kettering Cancer Center (New York, NY, USA). Eligible patients had measurable disease or non-measurable disease that was evaluable (defined by Response Evaluation Criteria in Solid Tumours [RECIST] version 1.1) and Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received FOLFOX chemotherapy (fluorouracil [400 mg/m2 bolus followed by 2400 mg/m2 over 48 h], leucovorin [400 mg/m2], and oxaliplatin [85 mg/m2]) and nivolumab (240 mg) intravenously on days 1 and 15, and oral regorafenib (80 mg) on days 1–21 of a 28-day cycle. Treatment was continued until disease progression (defined by RECIST version 1.1), unacceptable toxicity, or withdrawal of consent. The primary endpoint was 6-month progression-free survival in the per-protocol population (ie, all participants who received a dose of all study treatments). The regimen would be considered worthy of further investigation if at least 24 of 35 patients were progression free at 6 months. Safety was assessed in all participants who received at least one dose of any study treatment. This trial is registered with ClinicalTrials.gov, NCT04757363, and is now complete. Between Feb 11, 2021, and May 4, 2022, 39 patients were enrolled, received at least one dose of study drug, and were included in safety analyses. 35 patients were evaluable for 6-month progression-free survival. Median age was 57 years (IQR 52–66), nine (26%) patients were women, 26 (74%) were men, 28 (80%) were White, and seven (20%) were Asian. At data cutoff (March 3, 2023), median follow-up was 18·1 months (IQR 12·7–20·4). The primary endpoint was reached, with 25 (71%; 95% CI 54–85) of 35 patients progression free at 6 months. Nine (26%) of 35 patients had disease progression and one (3%) patient died; the death was unrelated to treatment. The most common adverse event of any grade was fatigue (36 [92%] of 39). The most common grade 3 or 4 adverse events were decreased neutrophil count (18 [46%]), hypertension (six [15%]), dry skin, pruritus, or rash (five [13%]), and anaemia (four [10%]). Serious treatment-related adverse events occurred in ten (26%) patients, which were acute kidney injury (three [8%]), hepatotoxicity (two [5%]), sepsis (two [5%]), dry skin, pruritus, or rash (one [3%]), nausea (one [3%]), and gastric perforation (one [3%]). There were no treatment-related deaths. Regorafenib can be safely combined with nivolumab and chemotherapy and showed promising activity in HER2-negative metastatic oesophagogastric cancer. A randomised, phase 3 clinical trial is planned. Bristol Myers Squibb, Bayer and National Institutes of Health/National Cancer Institute.
Sequencing of 279 cancer genes in ampullary carcinoma reveals trends relating to histologic subtypes and frequent amplification and overexpression of ERBB2 (HER2)
The biological relevance of histological subtyping of ampullary carcinoma into intestinal vs pancreaticobiliary types remains to be determined. In an effort to molecularly profile these subtypes of ampullary carcinomas, we conducted a two-phase study. In the discovery phase, we identified 18 pancreatobiliary-type ampullary carcinomas and 14 intestinal-type ampullary carcinomas using stringent pathologic criteria and performed next-generation sequencing targeting 279 cancer-associated genes on these tumors. Although the results showed overlapping of genomic alterations between the two subtypes, trends including more frequent KRAS alterations in pancreatobiliary-type ampullary carcinoma (61 vs 29%) and more frequent mutations in APC in intestinal-type ampullary carcinoma (43 vs 17%) were observed. Of the entire cohort of 32 tumors, the most frequently mutated gene was TP53 ( n =17); the most frequently amplified gene was ERBB2 ( n =5); and the most frequently deleted gene was CDKN2A ( n =6). In the second phase of the study, we aimed at validating our observation on ERBB2 and assessed ERBB2 amplification and protein overexpression in a series of 100 ampullary carcinomas. We found that (1) gene amplification and immunohistochemical overexpression of ERBB2 occurred in 13% of all ampullary carcinomas, therefore providing a potential target for anti-HER2 therapy in these tumors; (2) amplification and immunohistochemical expression correlated in all cases, thus indicating that immunohistochemistry could be used to screen tumors; and (3) none of the 14 ERBB2- amplified tumors harbored any downstream driver mutations in KRAS / NRAS, whereas 56% of the cases negative for ERBB2 amplification did, an observation clinically pertinent as downstream mutations may cause primary resistance to inhibition of EGFR family members.