Publications by authors named "Alexander S Baras"

Pathologic response is an endpoint in many ongoing clinical trials for neoadjuvant regimens, including immune checkpoint blockade and chemotherapy. Whole-slide scanning of glass slides generates high-resolution digital images and allows for remote review and potential measurement with image analysis tools, but concordance of pathologic response assessment on digital scans compared with that on glass slides has yet to be evaluated. Such a validation goes beyond previous concordance studies, which focused on establishing surgical pathology diagnoses, as it requires quantitative assessment of tumor, necrosis, and regression.

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An integral stage in typical digital pathology workflows involves deriving specific features from tiles extracted from a tessellated whole-slide image. Notably, various computer vision neural network architectures, particularly the ImageNet pretrained, have been extensively used in this domain. This study critically analyzes multiple strategies for encoding tiles to understand the extent of transfer learning and identify the most effective approach.

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Advancements in imaging technologies have revolutionized our ability to deeply profile pathological tissue architectures, generating large volumes of imaging data with unparalleled spatial resolution. This type of data collection, namely, spatial proteomics, offers invaluable insights into various human diseases. Simultaneously, computational algorithms have evolved to manage the increasing dimensionality of spatial proteomics inherent in this progress.

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Article Synopsis
  • - The study challenges traditional methods of evaluating potential clinical biomarkers like tumor mutational burden (TMB), which typically use a single cutoff to categorize patients, and highlights the limitations of this approach when relationships are non-monotonic.
  • - Researchers propose a two-cutoff method and the application of neural networks to accurately represent complex relationships between TMB and patient outcomes.
  • - Findings indicate that while TMB often shows a simple relationship with survival, there are exceptions, emphasizing the need for more flexible models in biomarker analysis.
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Human tissue, which is inherently three-dimensional (3D), is traditionally examined through standard-of-care histopathology as limited two-dimensional (2D) cross-sections that can insufficiently represent the tissue due to sampling bias. To holistically characterize histomorphology, 3D imaging modalities have been developed, but clinical translation is hampered by complex manual evaluation and lack of computational platforms to distill clinical insights from large, high-resolution datasets. We present TriPath, a deep-learning platform for processing tissue volumes and efficiently predicting clinical outcomes based on 3D morphological features.

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Large-scale genomic data are well suited to analysis by deep learning algorithms. However, for many genomic datasets, labels are at the level of the sample rather than for individual genomic measures. Machine learning models leveraging these datasets generate predictions by using statically encoded measures that are then aggregated at the sample level.

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  • The text discusses the need for standardized common data models (CDMs) in precision oncology to enhance clinical decision-making through initiatives like Molecular Tumor Boards (MTBs), which analyze clinical-genomic data for tailored therapies.
  • The authors developed a new precision oncology core data model called Precision-DM by building on existing models like mCODE, incorporating key elements such as next-generation sequencing and variant annotations, ultimately comprising 16 profiles and 355 data elements.
  • The findings showed that Precision-DM largely overlaps with existing models (50.7% with mCODE), demonstrating better coverage of mCODE elements but much less with others, indicating it could support standardized data sharing across healthcare systems.
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Background: Tumor mutational burden (TMB) has been investigated as a biomarker for immune checkpoint blockade (ICB) therapy. Increasingly, TMB is being estimated with gene panel-based assays (as opposed to full exome sequencing) and different gene panels cover overlapping but distinct genomic coordinates, making comparisons across panels difficult. Previous studies have suggested that standardization and calibration to exome-derived TMB be done for each panel to ensure comparability.

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  • Scientists are using a method called T cell receptor (TCR) sequencing to understand how the immune system responds to cancer.
  • A new AI tool called DeepTCR helps predict how well patients will respond to cancer treatments by analyzing specific parts of the TCR sequences.
  • The study finds that patients who don't respond to treatment have lots of T cells that should fight tumors, but these cells change a lot and don't work properly.
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  • The RAS family of GTPases, often mutated in various cancers, was analyzed across 66,372 tumors to understand how RAS mutations affect other genes and overall cancer characteristics.
  • The study revealed that RAS mutations show different patterns of co-mutations with non-RAS genes, influenced by the type of cancer, patient demographics, and genetic factors, particularly noting distinctions in KRAS G12C-mutant lung cancer.
  • Findings suggest that understanding the genomic differences in RAS-mutant tumors can help develop targeted therapies and improve clinical outcomes, especially with immunotherapy strategies.
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Characterizing likelihood of response to neoadjuvant chemotherapy (NAC) in muscle-invasive bladder cancer (MIBC) is an important yet unmet challenge. In this study, a machine-learning framework is developed using imaging of biopsy pathology specimens to generate models of likelihood of NAC response. Developed using cross-validation (evaluable N = 66) and an independent validation cohort (evaluable N = 56), our models achieve promising results (65%-73% accuracy).

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  • Multiplex immunofluorescence (mIF) allows detailed analysis of the tumor microenvironment, but its data interpretation can be complicated and labor-intensive.
  • Researchers developed a mIF data analysis pipeline using sample data from 93 metastatic melanoma patients, focusing on preserving spatial information at a single-cell level.
  • The study revealed significant correlations between cell densities from image cytometry and digital pathology, showcasing spatial clusters that could predict clinical outcomes and highlighting specific immune cell interactions relevant to tumor behavior.
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SARS-CoV-2 infection is characterized by a highly variable clinical course with patients experiencing asymptomatic infection all the way to requiring critical care support. This variation in clinical course has led physicians and scientists to study factors that may predispose certain individuals to more severe clinical presentations in hopes of either identifying these individuals early in their illness or improving their medical management. We sought to understand immunogenomic differences that may result in varied clinical outcomes through analysis of T-cell receptor sequencing (TCR-Seq) data in the open access ImmuneCODE database.

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Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML), classified by a translocation between chromosomes 15 and 17 [t(15;17)], that is considered a true oncologic emergency though appropriate therapy is considered curative. Therapy is often initiated on clinical suspicion, informed by both clinical presentation as well as direct visualization of the peripheral smear. We hypothesized that genomic imprinting of morphologic features learned by deep learning pattern recognition would have greater discriminatory power and consistency compared to humans, thereby facilitating identification of t(15;17) positive APL.

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Deep learning algorithms have been utilized to achieve enhanced performance in pattern-recognition tasks. The ability to learn complex patterns in data has tremendous implications in immunogenomics. T-cell receptor (TCR) sequencing assesses the diversity of the adaptive immune system and allows for modeling its sequence determinants of antigenicity.

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  • The study investigates how bladder cancer cells resist cisplatin-based chemotherapy, focusing on the role of androgen receptor (AR) activity and the signaling pathway of extracellular signal-regulated kinase (ERK).
  • BXDC2, a protein influenced by AR, was found to be downregulated in cisplatin-resistant bladder cancer cells, and knocking it down further increased resistance to cisplatin.
  • Immunohistochemistry revealed BXDC2 was less expressed in higher-grade tumors and AR-positive cases, and BXDC2 positivity suggested a better prognosis and response to chemotherapy in muscle-invasive bladder cancer patients.
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  • The College of American Pathologists has been providing guidelines for cancer pathology reporting for over 35 years, which help standardize the process for pathologists.
  • The integration of these guidelines into electronic health records and lab systems allows pathologists to streamline reporting and ensures the data is collected in a consistent format for cancer surveillance.
  • The paper discusses the history and current use of these cancer reporting tools, while also exploring future plans to enhance their incorporation into various healthcare and research workflows.
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In this study, we incorporate analyses of genome-wide sequence and structural alterations with pre- and on-therapy transcriptomic and T cell repertoire features in immunotherapy-naive melanoma patients treated with immune checkpoint blockade. Although tumor mutation burden is associated with improved treatment response, the mutation frequency in expressed genes is superior in predicting outcome. Increased T cell density in baseline tumors and dynamic changes in regression or expansion of the T cell repertoire during therapy distinguish responders from non-responders.

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Despite progress in immunotherapy, identifying patients that respond has remained a challenge. Through analysis of whole-exome and targeted sequence data from 5,449 tumors, we found a significant correlation between tumor mutation burden (TMB) and tumor purity, suggesting that low tumor purity tumors are likely to have inaccurate TMB estimates. We developed a new method to estimate a corrected TMB (cTMB) that was adjusted for tumor purity and more accurately predicted outcome to immune checkpoint blockade (ICB).

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The efficacy of cisplatin-based chemotherapy in patients with bladder cancer is often limited due to the development of therapeutic resistance. Our recent findings in bladder cancer suggested that activation of prostaglandin receptors ( EP2, EP4) or cyclooxygenase (COX)-2 induced cisplatin resistance. Meanwhile, emerging evidence indicates the involvement of estrogen receptor-β (ERβ) signals in urothelial cancer progression.

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We found that FOXO1-shRNA sublines or FOXO1-positive cells co-treated with a FOXO1 inhibitor were significantly more resistant to cisplatin treatment at pharmacological concentrations, compared with respective control sublines or those with mock treatment. Western blot demonstrated considerable increases in the expression levels of a phosphorylated inactive form of FOXO1 (p-FOXO1) in cisplatin-resistant sublines established by long-term culture with low/increasing doses of cisplatin, compared with respective controls. Immunohistochemistry in surgical specimens from patients with muscle-invasive bladder cancer undergoing cisplatin-based neoadjuvant therapy further showed a strong trend to associate between p-FOXO1 positivity and unfavorable response to chemotherapy.

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Androgen receptor (AR) and estrogen receptor-β (ERβ) have been implicated in urothelial tumor outgrowth as promoters, while underlying mechanisms remain poorly understood. Our transcription factor profiling previously performed identified FOXO1 as a potential downstream target of AR in bladder cancer cells. We here investigated the functional role of FOXO1 in the development and progression of urothelial cancer in relation to AR and ERβ signals.

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Purpose: The potential biological determinants of aggressive prostate cancer in African American (AA) men are unknown. Here we characterize prostate cancer genomic alterations in the largest cohort to date of AA men with clinical follow-up for metastasis, with the aim to elucidate the key molecular drivers associated with poor prognosis in this population.

Experimental Design: Targeted sequencing was retrospectively performed on 205 prostate tumors from AA men treated with radical prostatectomy (RP) to examine somatic genomic alterations and percent of the genome with copy-number alterations (PGA).

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Intraductal carcinoma of the prostate (IDC-P) has been recently recognized by the World Health Organization classification of prostatic tumors as a distinct entity, most often occurring concurrently with invasive prostatic adenocarcinoma (PCa). Whether documented admixed with PCa or in its rare pure form, numerous studies associate this entity with clinical aggressiveness. Despite increasing clinical experience and requirement of IDC-P documentation in protocols for synoptic reporting, the specifics of its potential contribution to assessment of grade group (GG) and cancer quantitation of PCa in both needle biopsies (NBx) and radical prostatectomy (RP) specimens remain unclear.

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