Publications by authors named "Timothy A Chan"

Tumor immunotherapy is supported by low-grade inflammatory conditions at the microenvironment, triggered by immunogenic cell death (ICD). However, ICD is dampened when tumors acquire resistance, affecting immune recognition. KDEL receptors (KDELRs), through a retrograde Golgi-to-ER transport, prevent spontaneous secretion of KDEL proteins.

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To understand genetic evolution in cancer during metastasis, we analyzed genomic profiles of 3,732 cancer patients in whom several tumor sites were longitudinally biopsied. During distant metastasis, tumors were observed to accumulate copy number alterations (CNAs) to a much greater degree than mutations. In particular, the development of whole genome duplication was a common event during metastasis, emerging de novo in 28% of patients.

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The annual ImmunoRad Conference has established itself as a recurrent occasion to explore the possibility of combining radiation therapy (RT) and immunotherapy (IT) for clinical cancer management. Bringing together a number of preclinical and clinical leaders in the fields of radiation oncology, immuno-oncology and IT, this annual event fosters indeed essential conversations and fruitful exchanges on how to address existing challenges to expand the therapeutic value of RT-IT combinations. The 8th edition of the ImmunoRad Conference, which has been held in October 2024 at the Weill Cornell Medical College of New York City, highlighted exciting preclinical and clinical advances at the interface between RT and IT, setting the stage for extra progress toward extended benefits for patients with an increasing variety of tumor types.

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Purpose/objective: Radiation necrosis (RN) is a potential complication after stereotactic radiosurgery (SRS) for brain metastases. This study develops a recursive partitioning analysis (RPA) to identify patients at risk for RN following SRS.

Methods: Patients who underwent single-fraction SRS for intact brain metastases at a single institution from 2017 to 2021 were identified.

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Cell therapy with tumor-infiltrating lymphocytes (TILs) has yielded durable responses for multiple cancer types, but the causes of therapeutic resistance remain largely unknown. Here multidimensional analysis was performed on time-serial tumor and blood in a lung cancer TIL therapy trial. Using T cell receptor sequencing on both functionally expanded T cells and neoantigen-loaded tetramer-sorted T cells, we identified tumor antigen-specific T cell receptors.

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Several FDA-approved anti-PD-L1 (programmed cell death ligand-1) monoclonal antibodies (mAbs) are used to treat cancer. While these mAbs primarily target and intercept PD-L1:PD-1 inhibitory signaling in T-cells, the Fc-domains of these mAbs are distinct, and the unique cellular cascades triggered by differing Fc-domains of PD-L1 mAbs have not been directly investigated. In this study, we compared the innate immune effects of two widely used anti-PD-L1 IgG1 mAbs which bear distinct Fc-domains, avelumab (native-Fc) and durvalumab (mutated-Fc), using two-cell and three-cell co-culture systems containing Natural Killer cells (NK-cells), dendritic cells (DCs) and various tumor cell lines of multiple cancer origins.

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Immune checkpoint inhibitors (ICIs) have improved outcomes of patients with many different cancers. These antibodies target molecules such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4) which normally function to limit immune activity. Treatment with ICIs reactivates T cells to destroy tumor cells in a highly specific manner, which in some patients, results in dramatic remissions and durable disease control.

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Importance: Immune checkpoint inhibitors (ICIs) have been approved for treatment of microsatellite instable (MSI-H) metastatic colorectal cancer (mCRC), but factors associated with receipt and efficacy of ICIs in routine clinical practice remain largely unknown.

Objective: To identify factors associated with receipt of ICIs and associated survival outcomes among patients with mCRC in routine clinical practice.

Design, Setting, And Participants: This population-based cohort study used deidentified data from a nationwide electronic health record-derived database to include 18 932 patients diagnosed with mCRC between January 2013 and June 2019.

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Unlabelled: Non-muscle invasive bladder cancer (NMIBC) represents 70-80% patients with newly diagnosed bladder cancer, and Bacillus Calmette-Guérin (BCG) remains a cornerstone treatment for intermediate-and high-risk NMIBC to prevent disease recurrence and progression. However, many patients experience recurrence after induction BCG, posing significant challenges in the management of the disease. We conducted single cell RNA sequencing on freshly collected NMIBC samples, distinguishing between those naïve to BCG treatment and those that recurred post-BCG treatment.

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We sought to identify the immunobiologic underpinnings of cardiac involvement as a postacute sequela of coronavirus disease 2019 (COVID-19) by comparing acute and convalescent populations. For the latter, an integrated analysis of cytokine levels, cardiac magnetic resonance imaging, and cardiopulmonary exercise capacity was performed. Unlike acute cardiac injury, which was associated with heightened tumor necrosis factor alpha (TNF-α) but not interleukin 18 (IL-18), convalescent myocardial inflammation/edema correlated with IL-18 but not TNF-α.

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Most patients with colorectal cancer do not achieve durable clinical benefits from immunotherapy, underscoring the existence of alternative immunosuppressive mechanisms. Here we found that activation of the lactate receptor HCAR1 signaling pathway induced the expression of chemokines CCL2 and CCL7 in colorectal tumor cells, leading to the recruitment of immunosuppressive CCR2 polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) to the tumor microenvironment. Ablation of Hcar1 in mice with colorectal tumors significantly decreased the abundance of tumor-infiltrating CCR2 PMN-MDSCs, enhanced the activation of CD8 T cells and, consequently, reduced tumor burden.

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Background: Plasma cell-free Human Papillomavirus DNA (cfHPVDNA) is a biomarker for oropharyngeal carcinoma. Existing diagnostics may be limited by inadequate sensitivity or high cost/complexity for longitudinal monitoring.

Objectives: We hypothesized that sensitive and specific plasma cfHPVDNA detection may be achieved via a highly-multiplex qPCR method.

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Article Synopsis
  • Superficial malignant peripheral nerve sheath tumors (SF-MPNSTs) are rare cancers that share some features with spindle cell melanomas and desmoplastic melanomas, but their biological characteristics remain poorly understood.* -
  • A study comparing SF-MPNST to other tumor types through whole-exome and RNA sequencing found that SF-MPNST had an intermediate tumor mutational burden and distinct gene expression patterns, indicating differences among these cancer types.* -
  • Immunohistochemical analysis revealed notable differences in markers like H3K27me3 and PRAME between SF-MPNST and other cancers, suggesting potential for new diagnostic markers and insights into tumor behavior.*
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Article Synopsis
  • The "three Es" model describes how the immune system keeps cancer cells in check until they gain traits that allow them to escape immune detection.
  • A new framework called the "three Cs" explains how cancer cells evade the immune system through camouflage, coercion, and cytoprotection.
  • Improving cancer treatments requires blocking these escape mechanisms to enhance the effectiveness of both immunotherapy and conventional therapies.
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Neoantigen immunoediting drives immune checkpoint blockade efficacy, yet the molecular features of neoantigens and how neoantigen immunogenicity shapes treatment response remain poorly understood. To address these questions, 80 patients with non-small cell lung cancer were enrolled in the biomarker cohort of CheckMate 153 (CA209-153), which collected radiographic guided biopsy samples before treatment and during treatment with nivolumab. Early loss of mutations and neoantigens during therapy are both associated with clinical benefit.

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The incidence of colorectal cancer (CRC) among individuals younger than age 50 (early-onset CRC [EOCRC]) has substantially increased, and yet the etiology and molecular mechanisms underlying this alarming rise remain unclear. We compared tumor-associated T-cell repertoires between EOCRC and average-onset CRC (AOCRC) to uncover potentially unique immune microenvironment-related features by age of onset. Our discovery cohort included 242 patients who underwent surgical resection at Cleveland Clinic from 2000 to 2020.

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Article Synopsis
  • Immunologic recognition of peptide antigens bound to class I MHC molecules is crucial for immunotherapy and human health, but current prediction methods primarily focus on simple sequence information, which can miss complex molecular interactions.
  • Artificial intelligence (AI) techniques, both unsupervised and supervised, can enhance our understanding and prediction of MHC-peptide immunogenicity by analyzing large molecular dynamics simulations.
  • These AI methods not only uncover subtle features that differentiate immunogenicity between cancer neoantigens and their counterparts but also outperform traditional sequence models, providing insights into the structural and dynamic factors that influence T cell response and therapeutic receptor design.
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Tumors develop by invoking a supportive environment characterized by aberrant angiogenesis and infiltration of tumor-associated macrophages (TAMs). In a transgenic model of breast cancer, we found that TAMs localized to the tumor parenchyma and were smaller than mammary tissue macrophages. TAMs had low activity of the metabolic regulator mammalian/mechanistic target of rapamycin complex 1 (mTORC1), and depletion of negative regulator of mTORC1 signaling, tuberous sclerosis complex 1 (TSC1), in TAMs inhibited tumor growth in a manner independent of adaptive lymphocytes.

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Purpose: A single arm, phase II trial of carboplatin, nab-paclitaxel, and pembrolizumab (CNP) in metastatic triple-negative breast cancer (mTNBC) was designed to evaluate overall response rate (ORR), progression-free survival (PFS), duration of response (DOR), safety/tolerability, overall survival (OS), and identify pathologic and transcriptomic correlates of response to therapy.

Patients And Methods: Patients with ≤2 prior therapies for metastatic disease were treated with CNP regardless of tumor programmed cell death-ligand 1 status. Core tissue biopsies were obtained prior to treatment initiation.

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Article Synopsis
  • Cancer progression involves malignant cells evading immune system control, making it essential for treatments to restore this control for effective management.
  • Various therapies, including immunotherapies and traditional treatments like chemotherapy and radiation, benefit from strategies that induce immunogenic cell death, promoting an immune response against tumor cells.
  • Combining different therapies, such as chemoimmunotherapy and multiple immune checkpoint inhibitors, shows promise for treating advanced cancers, although it often comes with increased side effects.
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  • Salivary gland cancers (SGCs) are rare and aggressive, often lacking effective treatments when they spread, prompting a phase 2 trial of nivolumab and ipilimumab in 64 metastatic SGC patients.
  • Results showed some success in "other SGCs" cohort (16% response) but limited efficacy in adenoid cystic carcinoma (6% response), with notable adverse events occurring in 38% of patients.
  • Genetic and immune cell analyses indicated that responding tumors had active T cell responses and certain neoantigens, suggesting a potential path for treatment in non-ACC SGCs like salivary duct carcinomas.
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Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of multiple cancer types. However, only a fraction of patients with cancer responds to ICIs employed as stand-alone therapeutics, calling for the development of safe and effective combinatorial regimens to extend the benefits of ICIs to a larger patient population. In addition to exhibiting a good safety and efficacy profile, targeted radionuclide therapy (TRT) with radiopharmaceuticals that specifically accumulate in the tumor microenvironment has been associated with promising immunostimulatory effects that (at least in preclinical cancer models) provide a robust platform for the development of TRT/ICI combinations.

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Article Synopsis
  • Recurrent and metastatic head and neck squamous cell carcinoma (HNSCC) has poor survival rates and limited effectiveness of immune checkpoint blockade (ICB) therapies, with current biomarkers like tumor mutational burden (TMB) offering only modest predictive value.
  • A study of 133 ICB-treated patients identified 6 distinct molecular subtypes of HNSCC tumors, which showed varied response rates to treatment and were separately validated in another patient group.
  • Researchers developed a predictive model using clinical and genomic features that more accurately forecasted patient outcomes compared to TMB alone, establishing a tool that can improve risk stratification for patients eligible for ICB treatment.
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