Publications by authors named "Brent Larson"

Aims: Metastatic tumors to the stomach can mimic primary gastric adenocarcinoma or be subtle and difficult to identify. The current study aimed to characterize the clinicopathology of metastases to the stomach to aid in diagnosis.

Methods And Results: Forty-three metastatic tumors and 30 primary gastric adenocarcinoma cases were reviewed.

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Acetyl-CoA carboxylase catalyzes the first committed and regulated step in fatty acid synthesis in all animals, plants and bacteria. In most Gram-positive and Gram-negative bacteria, the enzyme is composed of three proteins: biotin carboxylase, biotin carboxyl carrier protein and carboxyltransferase. The reaction consists of two half-reactions.

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Article Synopsis
  • Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer deaths, and the rare adenosquamous carcinoma of the pancreas (ASCP) makes up only 1-10% of these cases, with unclear treatment options due to exclusion from standard chemotherapy trials.
  • A case study of a 68-year-old man with metastatic ASCP and a KRAS G12C mutation shows that he responded well to pembrolizumab, an immune checkpoint inhibitor, despite ongoing challenges with traditional therapies.
  • This patient's positive response to ICI suggests that the unique tumor characteristics of ASCP may warrant more research, leading to ongoing clinical trials focusing on immune-based treatments for this rare subtype of pancreatic cancer.
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Introduction: Upper gastrointestinal (UGI) cancers, comprising malignancies of the esophagus, stomach, duodenum, pancreas, liver, biliary tract, and gallbladder, are the second leading cause of cancer-related mortality in the United States and are associated with significant comorbidities. Recent studies show a disproportionate rise in pancreatic and stomach cancer among young adults. This study aims to use a nationwide, population-based cohort to (i) evaluate the trend of all UGI cancer as an aggregate and (ii) examine the role of demographics, histology, and tumor stage in UGI cancer incidence among young adults.

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Several professional society guidelines suggest germline genetic testing for colorectal polyposis syndromes in patients with ≥10 lifetime adenomatous polyps. This study evaluated the factors associated with genetic testing decisions and outcomes when germline testing was recommended per guidelines. Surgical archives revealed 145 patients with a recommendation for germline genetic polyposis testing based on guidelines.

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Background: Checkpoint kinase 2 is a tumor suppressor gene in the DNA damage checkpoint system that may be mutated in several cancers. Patients with germline checkpoint kinase 2 mutations and multiple colon polyps were noted during routine care, and genetic testing is recommended for patients with as few as 10 lifetime polyps.

Objective: This study assessed whether checkpoint kinase 2 is associated with attenuated or oligopolyposis and characterized the GI clinicopathologic profile.

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Background: The immune microenvironment impacts tumor growth, invasion, metastasis, and patient survival and may provide opportunities for therapeutic intervention in pancreatic ductal adenocarcinoma (PDAC). Although never studied as a potential modulator of the immune response in most cancers, Keratin 17 (K17), a biomarker of the most aggressive (basal) molecular subtype of PDAC, is intimately involved in the histogenesis of the immune response in psoriasis, basal cell carcinoma, and cervical squamous cell carcinoma. Thus, we hypothesized that K17 expression could also impact the immune cell response in PDAC, and that uncovering this relationship could provide insight to guide the development of immunotherapeutic opportunities to extend patient survival.

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Objectives: To determine the role of keratin 17 (K17) as a predictive biomarker for response to chemotherapy by defining thresholds of K17 expression based on immunohistochemical tests that could be used to optimize therapeutic intervention for patients with pancreatic ductal adenocarcinoma (PDAC).

Methods: We profiled K17 expression, a hallmark of the basal molecular subtype of PDAC, by immunohistochemistry in 2 cohorts of formalin-fixed, paraffin-embedded PDACs (n = 305). We determined a K17 threshold of expression to optimize prognostic stratification according to the lowest Akaike information criterion and explored the potential relationship between K17 and chemoresistance by multivariate predictive analyses.

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Oxygenic photosynthetic organisms use Photosystem II (PSII) to oxidize water and reduce plastoquinone. Here, we review the mechanisms by which PSII is assembled and turned over in the model green alga . This species has been used to make key discoveries in PSII research due to its metabolic flexibility and amenability to genetic approaches.

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In previous studies, a significant increase in the incidence of pancreatic cancer among younger women compared to men in the United States was noted. However, the specific histopathologic characteristics were not delineated. This population-based study aimed to assess whether this disproportionate rise in pancreatic cancer in younger women was contributed by pancreatic ductal adenocarcinoma (PDAC) or pancreatic neuroendocrine tumors (PanNET).

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Background: The immune microenvironment impacts tumor growth, invasion, metastasis, and patient survival and may provide opportunities for therapeutic intervention in pancreatic ductal adenocarcinoma (PDAC). Although never studied as a potential modulator of the immune response in most cancers, Keratin 17 (K17), a biomarker of the most aggressive (basal) molecular subtype of PDAC, is intimately involved in the histogenesis of the immune response in psoriasis, basal cell carcinoma, and cervical squamous cell carcinoma. Thus, we hypothesized that K17 expression could also impact the immune cell response in PDAC, and that uncovering this relationship could provide insight to guide the development of immunotherapeutic opportunities to extend patient survival.

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Objectives: Adenocarcinomas of the biliary tract frequently present diagnostic challenges because of their histologic overlap with benign and preinvasive lesions. The molecular profiles of biliary adenocarcinomas vary by anatomical location. Variations in IDH1/2, common in intrahepatic cholangiocarcinoma, can lead to defective production of 5-hydroxymethylcytosine (5-hmC).

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Aims: Pre-exposure prophylaxis (PrEP) consists of combination antiretroviral therapy and is increasingly utilized to prevent human immunodeficiency virus (HIV) in high-risk populations. Two index cases noted during routine care showed markedly increased duodenal villous surface apoptosis in patients on PrEP. We sought to examine the prevalence of this finding and identify any clinicopathologic correlations.

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Arginase-1 (Arg1) and hepatocyte paraffin antigen 1 (HepPar1) are specific and sensitive markers of hepatocellular differentiation. HepPar1 is a granular cytoplasmic immunostain that may be negative in hepatocellular carcinoma (HCC) with cytoplasmic clearing. Arg1 shows uniform cytoplasmic positivity and frequent nuclear positivity.

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Capecitabine is a commonly used oral chemotherapeutic agent. Gastrointestinal (GI) side effects are clinically well-known, however, the histopathologic changes have not been comprehensively studied. This study describes the largest case series (8 patients) characterizing the histopathology of capecitabine-induced GI injury.

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Introduction: Artificial intelligence remote monitoring of clear aligner therapy has recently gained popularity. It uses deep learning algorithms on a patient's mobile smartphone to determine readiness to progress to the next aligner (ie, GO vs NO-GO) and identify areas in which the teeth are not tracking with the clear aligners. This study aimed to assess the repeatability of the Go or No-Go instructions provided by the application and to determine the 3-dimensional discrepancies that constitute an unseat.

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Objectives: This study examines the clinical-pathological profiles of patients with glycogenic hepatopathy in a contemporary cohort of patients at an adult acute care hospital.

Methods: Liver biopsies with glycogenic hepatopathy were retrieved from the departmental surgical pathology database, the histological findings were studied, and the clinical findings were reviewed.

Results: Five cases of glycogenic hepatopathy were found, including cases associated with type 1 diabetes mellitus (n = 1), type 2 diabetes mellitus (n = 1), corticosteroids (n = 2), and anorexia (n = 2, including the patient with type 1 diabetes).

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Background & Aims: Previous studies have shown an increasing incidence of pancreatic cancer (PC), especially in younger women; however, this has not been externally validated. In addition, there are limited data about contributing factors to this trend. We report age and sex-specific time-trend analysis of PC age-adjusted incidence rates (aIRs) using the National Program of Cancer Registries database without Surveillance Epidemiology and End Results data.

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Introduction: Hyaluronan (HA) accumulation is associated with tumorigenesis and aggressive tumor behavior.

Aims: We investigated the biomarker potential of HA in non-small cell lung cancer (NSCLC).

Methods: HA levels were scored using affinity histochemistry in 137 NSCLC samples stratified by HA score ≤10, 11-20, 21-30, and >30 with HA-high defined as ≥25% expression in the extracellular matrix (ECM) of the tumor surface area.

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Introduction: 3M Oral Care Solutions (St Paul, Minn) has recently introduced Clarity Aligners into the market. This cohort study evaluated the orthodontic treatment efficacy of this clear aligner system using the Peer Assessment Rating (PAR) index and the American Board of Orthodontics Cast-Radiograph Evaluation (CR-Eval).

Methods: Pretreatment and posttreatment dental models of 87 subjects who had undergone orthodontic treatment using Clarity Aligners in both arches to align their teeth to a target setup were independently evaluated by 4 examiners using the PAR index and the American Board of Orthodontics CR-Eval.

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Context.—: Claudin-18 is expressed in some gastric cancers. Clinical trials are evaluating it as a therapeutic target.

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Objectives: Neisseria gonorrhoeae infection of the anorectal tract is often asymptomatic and infrequently biopsied, but pathologists can be tasked with identifying the histologic features of possible infection. The study was undertaken to better characterize clinical and morphologic features of confirmed anorectal gonococcal infection.

Methods: From 2011 to 2020, 201 positive gonococcal nucleic acid amplification testing samples from 174 patients collected from the distal colorectum and/or anus were matched to eight patients with concurrent biopsy specimens of the distal anorectum.

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