Publications by authors named "Stephen Kazakoff"

Article Synopsis
  • The study followed patients with early-stage follicular lymphoma (ESFL) who were treated with involved field radiotherapy (IFRT) alone or combined with chemotherapy (cyclophosphamide/vincristine/prednisolone) and later added rituximab to the treatment, analyzing its effects over an 11.3-year period.* -
  • Results showed that those receiving IFRT plus rituximab (IFRT + R-CVP) had significantly better progression-free survival rates (62% vs. 43%) compared to IFRT alone, even though overall survival rates didn’t differ significantly.* -
  • Additionally, higher expression of the CD8A gene in biopsy samples was associated with improved outcomes, suggesting that immune
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Engagement of the T cell receptor (TCR) triggers molecular reprogramming leading to the acquisition of specialized effector functions by CD4 helper and CD8 cytotoxic T cells. While transcription factors, chemokines, and cytokines are known drivers in this process, the temporal proteomic and transcriptomic changes that regulate different stages of human primary T cell activation remain to be elucidated. Here, we report an integrative temporal proteomic and transcriptomic analysis of primary human CD4 and CD8 T cells following ex vivo stimulation with anti-CD3/CD28 beads, which revealed major transcriptome-proteome uncoupling.

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Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is often the only source of tumor tissue from patients with advanced, inoperable lung cancer. EBUS-TBNA aspirates are used for the diagnosis, staging, and genomic testing to inform therapy options. Here we extracted DNA and RNA from 220 EBUS-TBNA aspirates to evaluate their suitability for whole genome (WGS), whole exome (WES), and comprehensive panel sequencing.

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Introduction: Tumour Mutation Burden (TMB) is a potential biomarker for immune cancer therapies. Here we investigated parameters that might affect TMB using duplicate cytology smears obtained from endobronchial ultrasound transbronchial needle aspiration (EBUS TBNA)-sampled malignant lymph nodes.

Methods: Individual Diff-Quik cytology smears were prepared for each needle pass.

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Background: Cytology smears are commonly collected during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS TBNA) procedures but are rarely used for molecular testing. Studies are needed to demonstrate their great potential, in particular for the prediction of malignant cell DNA content and for utility in molecular diagnostics using large gene panels.

Methods: A prospective study was performed on samples from 66 patients with malignant lymph nodes who underwent EBUS TBNA.

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Unlabelled: Melanoma is a cancer of melanocytes, with multiple subtypes based on body site location. Cutaneous melanoma is associated with skin exposed to ultraviolet radiation; uveal melanoma occurs in the eyes; mucosal melanoma occurs in internal mucous membranes; and acral melanoma occurs on the palms, soles, and nail beds. Here, we present the largest whole-genome sequencing study of melanoma to date, with 570 tumors profiled, as well as methylation and RNA sequencing for subsets of tumors.

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Background: Malignant pleural mesothelioma (MPM) has a poor overall survival with few treatment options. Whole genome sequencing (WGS) combined with the immune features of MPM offers the prospect of identifying changes that could inform future clinical trials.

Methods: We analysed somatic mutations from 229 MPM samples, including previously published data and 58 samples that had undergone WGS within this study.

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Unlabelled: G9a and EZH2 are two histone methyltransferases commonly upregulated in several cancer types, yet the precise roles that these enzymes play cooperatively in cancer is unclear. We demonstrate here that frequent concurrent upregulation of both G9a and EZH2 occurs in several human tumors. These methyltransferases cooperatively repressed molecular pathways responsible for tumor cell death.

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Background: Endometrial cancer (EC) is a major gynecological cancer with increasing incidence. It comprises four molecular subtypes with differing etiology, prognoses, and responses to chemotherapy. In the future, clinical trials testing new single agents or combination therapies will be targeted to the molecular subtype most likely to respond.

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We concurrently examine the whole genome, transcriptome, methylome, and immune cell infiltrates in baseline tumors from 77 patients with advanced cutaneous melanoma treated with anti-PD-1 with or without anti-CTLA-4. We show that high tumor mutation burden (TMB), neoantigen load, expression of IFNγ-related genes, programmed death ligand expression, low PSMB8 methylation (therefore high expression), and T cells in the tumor microenvironment are associated with response to immunotherapy. No specific mutation correlates with therapy response.

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Immunopathology and intestinal stem cell (ISC) loss in the gastrointestinal (GI) tract is the prima facie manifestation of graft-versus-host disease (GVHD) and is responsible for significant mortality after allogeneic bone marrow transplantation (BMT). Approaches to prevent GVHD to date focus on immune suppression. Here, we identify interferon-λ (IFN-λ; interleukin-28 [IL-28]/IL-29) as a key protector of GI GVHD immunopathology, notably within the ISC compartment.

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Poxvirus systems have been extensively used as vaccine vectors. Herein a RNA-Seq analysis of intramuscular injection sites provided detailed insights into host innate immune responses, as well as expression of vector and recombinant immunogen genes, after vaccination with a new multiplication defective, vaccinia-based vector, Sementis Copenhagen Vector. Chikungunya and Zika virus immunogen mRNA and protein expression was associated with necrosing skeletal muscle cells surrounded by mixed cellular infiltrates.

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To increase understanding of the genomic landscape of acral melanoma, a rare form of melanoma occurring on palms, soles or nail beds, whole genome sequencing of 87 tumors with matching transcriptome sequencing for 63 tumors was performed. Here we report that mutational signature analysis reveals a subset of tumors, mostly subungual, with an ultraviolet radiation signature. Significantly mutated genes are BRAF, NRAS, NF1, NOTCH2, PTEN and TYRP1.

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The homologous recombination deficiency (HRD) score was developed using whole-genome copy number data derived from arrays as a way to infer deficiency in the homologous recombination DNA damage repair pathway (in particular or deficiency) in breast cancer samples. The score has utility in understanding tumour biology and may be indicative of response to certain therapeutic strategies. Studies have used whole-exome sequencing to derive the HRD score, however, with increasing use of whole-genome sequencing (WGS) to characterise tumour genomes, there has yet to be a comprehensive comparison between HRD scores derived by array versus WGS.

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Background: WNT activation is a hallmark of colorectal cancer. mutation is present in 15% of colorectal cancers, and the role of mutations in WNT signaling regulators in this context is unclear. Here, we evaluate the mutational landscape of WNT signaling regulators in mutant cancers.

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The serrated neoplasia pathway gives rise to a distinct subgroup of colorectal cancers distinguished by the presence of mutant BRAF and the CpG Island Methylator Phenotype (CIMP). BRAF mutant CRC are commonly associated with microsatellite instability, which have an excellent clinical outcome. However, a proportion of BRAF mutant CRC retain microsatellite stability and have a dismal prognosis.

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Article Synopsis
  • Researchers found important genetic changes linked to breast cancer that aren’t in the usual parts of genes, but in non-coding RNA, which seems to help control gene activity.
  • They discovered over 4,000 of these non-coding RNA genes and noticed that their levels vary between healthy and cancerous breast tissue.
  • The study suggests that these non-coding RNAs could be significant in understanding how genetic factors influence breast cancer risk.
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Background: Genome-wide association studies have identified 196 high confidence independent signals associated with breast cancer susceptibility. Variants within these signals frequently fall in distal regulatory DNA elements that control gene expression.

Results: We designed a Capture Hi-C array to enrich for chromatin interactions between the credible causal variants and target genes in six human mammary epithelial and breast cancer cell lines.

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Knowledge of key drivers and therapeutic targets in mucosal melanoma is limited due to the paucity of comprehensive mutation data on this rare tumor type. To better understand the genomic landscape of mucosal melanoma, here we describe whole genome sequencing analysis of 67 tumors and validation of driver gene mutations by exome sequencing of 45 tumors. Tumors have a low point mutation burden and high numbers of structural variants, including recurrent structural rearrangements targeting TERT, CDK4 and MDM2.

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Background & Aims: Colorectal cancer is an epigenetically heterogeneous disease, however, the extent and spectrum of the CpG island methylator phenotype (CIMP) is not clear.

Methods: Genome-scale methylation and transcript expression were measured by DNA Methylation and RNA expression microarray in 216 unselected colorectal cancers, and findings were validated using The Cancer Genome Atlas 450K and RNA sequencing data. Mutations in epigenetic regulators were assessed using CIMP-subtyped Cancer Genome Atlas exomes.

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The benign melanocytic nevus is the most common tumor in humans and rarely transforms into cutaneous melanoma. Elucidation of the nevus genome is required to better understand the molecular steps of progression to melanoma. We performed whole genome sequencing on a series of 14 benign melanocytic nevi consisting of both congenital and acquired types.

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Glioblastomas are the most common and lethal neoplasms of the central nervous system. Neighbouring glioma cells maintain extreme degrees of genetic and phenotypic variation that form intratumoural heterogeneity. This genetic diversity allows the most adaptive tumour clones to develop treatment resistance, ultimately leading to disease recurrence.

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Background: Next-generation sequencing (NGS) in lung cancer specimens from endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is usually performed on formalin-fixed paraffin-embedded cell block material.

Objectives: Since DNA can be damaged by this process, we investigated the potential of using DNA extracted from Diff-Quik cytology smears made for rapid on-site evaluation during EBUS-TBNA.

Methods: In a prospective study, 67 patients undergoing diagnostic EBUS-TBNA were ana-lysed.

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Background: Oesophageal adenocarcinoma (EAC) incidence is increasing and has a poor survival rate. Barrett's oesophagus (BE) is a precursor condition that is associated with EAC and often occurs in conjunction with chronic gastro-oesophageal reflux, however many individuals diagnosed with BE never progress to cancer. An understanding of the genomic features of BE and EAC may help with the early identification of at-risk individuals.

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Summary: Assessing the pathogenicity of genetic variants can be a complex and challenging task. Spliceogenic variants, which alter mRNA splicing, may yield mature transcripts that encode non-functional protein products, an important predictor of Mendelian disease risk. However, most variant annotation tools do not adequately assess spliceogenicity outside the native splice site and thus the disease-causing potential of variants in other intronic and exonic regions is often overlooked.

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