Citations

Aims Reticulin stain is used routinely in the histological evaluation of hepatocellular carcinoma (HCC). The goal of this study was to assess whether the histological reticulin proportionate area (RPA) in HCCs predicts tumour‐related outcomes. Methods and results We developed and validated a supervised artificial intelligence (AI) model that utilises a cloud‐based, deep‐learning AI platform (Aiforia Technologies, Helsinki, Finland) to specifically recognise and quantify the reticulin framework in normal livers and HCCs using routine reticulin staining. We applied this reticulin AI model to a cohort of consecutive HCC cases from patients undergoing curative resection between 2005 and 2015. A total of 101 HCC resections were included (median age = 68 years, 64 males, median follow‐up time = 49.9 months). AI model RPA reduction of > 50% (compared to normal liver tissue) was predictive of metastasis [hazard ratio (HR) = 3.76, P = 0.004, disease‐free survival (DFS, HR = 2.48, P < 0.001) and overall survival (OS), HR = 2.80, P = 0.001]. In a Cox regression model, which included clinical and pathological variables, RPA decrease was an independent predictor of DFS and OS and the only independent predictor of metastasis. Similar results were found in the moderately differentiated HCC subgroup (WHO grade 2), in which reticulin quantitative analysis was an independent predictor of metastasis, DFS and OS. Conclusion Our data indicate that decreased RPA is a strong predictor of various HCC‐related outcomes, including within the moderately differentiated subgroup. Reticulin, therefore, may represent a novel and important prognostic HCC marker, to be further explored and validated.

Abstract Background: Non-small cell lung cancer (NSCLC) tissue is a valuable resource for diagnosis, treatment planning, and drug development. Current 2D histopathological techniques introduce under-sampling error (i.e., a single 5 um section represents 0.5% of a 1 mm thick biopsy), interobserver variability, and fail to capture the biology contained within the entire tissue sample. We have developed a suite of technologies to stain, chemically clarify, image, visualize, and analyze entire intact NSCLC tissue samples. Methods: Human NSCLC tissue, stored frozen in OCT, was fixed in 4% paraformaldehyde, stained with nuclear (TOPRO-3) and general protein (Eosin) fluorescent dyes, and optically cleared using a modified iDISCO protocol with ethyl cinnamate as the refractive index matching solution. Whole, intact tissue samples, roughly 1-5mm3 in volume, were imaged at 2 microns/pixel resolution with an open-top light-sheet microscope (3Di, Alpenglow Biosciences). Smaller regions of interest (ROIs) with key pathologic features were reimaged at higher resolution, 0.17 microns/pixel, to reveal subnuclear features and for cell typing. Visualization was performed using Aivia software. Results: NSCLC tissue samples were successfully imaged in 3D. Low resolution images (2 microns/pixel) were obtained within 4-31 minutes, depending on the tissue volume. The 3D distribution of cancer cells, immune cells, vessels, and fibrosis varied substantially throughout the volume of the tissue. Recognizable histologic features, including nests of tumor cells surrounded by vasculature and immune cells, were readily visualized. Squamous and adenocarcinoma with its subtypes (solid, acinar, lepidic, and micropapillary) morphologies were recognizable in 2D optical sections of the 3D datasets. Imaging quality degraded in tissue deeper than 1 mm due to light scattering. Conclusion: We assessed intact NSCLC tissue samples measuring up to 5 mm3 using our custom light-sheet microscope and tissue clearing techniques. This novel method enables us to visualize key features of NSCLC such as the tumor interfaces, tertiary lymphoid structures, vessels and fibrosis in the entire tissue sample, preventing under sampling error, and potentially enabling new biologic insights. Next steps include segmentation and quantification of key tissue structures such as tumor volume, immune cell distribution, and fibrosis/immune cell exclusion. This proof-of-concept study provides motivation for further investigation into the significance of 3D tissue features in NSCLC tissue samples. Citation Format: Alexandra Alvarsson, Carl Storey, Brandy Olin Pope, Caleb Stoltzfus, Robert Vierkant, Jessica Tufariello, Aaron Bungum, Julia Naso, Cheuk Ki Chan, Eric Edell, Christopher Hartley, Janani Reisenauer, Nicholas Reder. 3D assessment of the lung cancer microenvironment using multi-resolution open-top light-sheet microscopy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6624.

AbstractBackgroundObtaining a diagnosis and treating pulmonary malignancies during the same anesthesia requires either an on‐site pathologist or a system for remotely evaluating microscopic images. Cytology specimens are challenging to remotely assess given the need to navigate through dispersed and three‐dimensional cell clusters. Remote navigation is possible using robotic telepathology, but data are limited on the ease of use of current systems, particularly for pulmonary cytology.MethodsAir dried modified Wright‐Giemsa stained slides from 26 touch preparations of transbronchial biopsies and 27 smears of endobronchial ultrasound guided fine needle aspirations were scored for ease of adequacy assessment and ease of diagnosis on robotic (rmtConnect Microscope) and non‐robotic telecytology platforms. Diagnostic classifications were compared between glass slides and the robotic and non‐robotic telecytology assessments.ResultsCompared to non‐robotic telecytology, robotic telecytology had a greater ease of adequacy assessment and non‐inferior ease of diagnosis. The median time to diagnosis using robotic telecytology was 85 s (range 28–190 s). Diagnostic categories were concordant for 76% of cases in robotic versus non‐robotic telecytology and 78% of cases in robotic telecytology versus glass slide diagnosis. Weighted Cohen's kappa scores for agreement in these comparisons were 0.84 and 0.72, respectively.ConclusionsUse of a remote‐controlled robotic microscope improved the ease of adequacy assessment compared to non‐robotic telecytology and enabled strongly concordant diagnoses to be expediently rendered. This study provides evidence that modern robotic telecytology is a feasible and user‐friendly method of remotely and potentially intraoperatively rendering adequacy assessments and diagnoses on bronchoscopic cytology specimens.

2616 Background: Non-small cell lung cancer (NSCLC) tissue is a valuable resource for diagnosis, treatment planning, and drug development. Current 2D histopathological techniques introduce under-sampling error (i.e., a single 5 µm section represents 0.5% of a 1 mm thick biopsy), interobserver variability, and failure to capture the biology contained within the entire tissue sample. We have developed a suite of technologies to stain, chemically clarify, image, visualize, and analyze entire, intact lung tissue samples. Herein, we present analysis methods for comprehensive 3D assessment of intact NSCLC tissue. Methods: Human NSCLC tissue, stored frozen in optimal cutting temperature (OCT) compound, was fixed in 4% paraformaldehyde, stained with nuclear (TOPRO-3) and general protein (Eosin) fluorescent dyes, and optically cleared using a modified iDISCO protocol with ethyl cinnamate as the refractive index matching solution. Twenty tissue samples measuring 1-5 mm3 in volume were imaged at 2 µm/pixel resolution with a hybrid open-top light-sheet microscope. Smaller regions of interest (ROIs) with interesting pathologic features were re-imaged at higher resolution, 0.17 µm/pixel. Visualization and analysis was performed using Aivia software, custom spatial analysis software and python scripts. Results: All NSCLC tissue samples were successfully imaged in 3D at both low and high resolution. Computational approaches, such as machine learning, were used to segment and classify tumor cells and lymphocytes within the high resolution ROIs. In one example we quantified a 0.0045 mm3 ROI containing 1x109 voxels. We segmented 1,474 unique objects, and classified 683 (46%) of the objects as lymphocytes and 309 (20%) of the cells as tumor cells. We found that on average the lymphocytes were within 12 µm of the nearest tumor cell. Additionally the tissue was broken into separate lymphocyte dense (58% of volume) and tumor dense regions (42% of volume). Further analysis is in progress to quantify more features, such as tertiary lymphoid structures, stromal cells, and fibrosis over the full 20 sample dataset. Conclusions: We successfully implemented 3D machine learning analysis pipelines using images from intact NSCLC tissue samples measuring up to 5 mm3. The imaging was performed using our custom hybrid open-top light-sheet microscope. This novel method enables us to identify and quantify key histological features such as tumor cells and lymphocytes within the tumor microenvironment. In addition, machine learning driven algorithms clustered cells into distinct tissue regions in 3D which enables a more precise assessment of disease state and heterogeneity. Further investigation is ongoing to link these results to patient outcomes.

AbstractIntroductionIn evaluating malignant pleural fluid cytology, metastatic adenocarcinomas and mesotheliomas are often differential diagnoses. GATA binding protein 3 (GATA3) has historically been used to confirm metastatic breast carcinomas; however, GATA3 has low specificity if mesothelioma is included in differential diagnoses. Trichorhinophalangeal syndrome type 1 (TRPS1) protein is expressed in all types of breast carcinomas, with reported high specificity and sensitivity. We investigated the performance of TRPS1 immunohistochemistry (IHC) and compared it to GATA3 in pleural fluids diagnosed with metastatic breast carcinoma and mesothelioma.MethodsThirty‐six consecutive ThinPrep pleural fluids and 4 pleural fine needle aspirations (FNAs) with diagnoses of metastatic breast carcinoma (21) and mesothelioma (19) were retrieved, and IHC with TRPS1 and GATA3 was performed on all. Immunoreactivity scores for TRPS1 were calculated by multiplying percentage of immunoreactive cells by staining intensity. Immunoreactivity scores were negative if 0 or 1, low positive if 2, intermediate positive if 3 or 4, or high positive if 6 or 9. Nuclear immunoreactivity of ≥10% with at least moderate intensity was judged GATA3 positive.ResultsGATA3 showed immunoreactivity in all metastatic breast carcinomas and 84% of mesotheliomas. TRPS1 was immunoreactive in all breast carcinoma cases (18 with a score of 9 and 3 with a score of 6). TRPS1 showed low positivity in 5% of mesothelioma cases with all other cases being negative.ConclusionWhen cytomorphologic differential diagnoses of mesothelioma exist, TRPS1 is a more specific marker than GATA3 for confirmation of metastatic breast carcinoma in pleural fluid cytology.

AbstractLymphangioleiomyomatosis (LAM) is a rare disease with variable presentations. The neoplastic cells in LAM demonstrate a unique and diagnostically important “myomelanocytic” phenotype. Cytologic reports of LAM are infrequent and have not in the past emphasized the floating island pattern in which circumscribed aggregates of lesional cells are rimmed by appliques of flattened endothelium. This case illustrates the cytology of LAM and emphasizes that the floating island cytoarchitectural pattern more classically associated with entities such as hepatocellular carcinomas may be seen in cytological preparations of LAM at unanticipated body sites.

Abstract Background and study aims The risk of bleeding with endoscopic ultrasound-guided tissue acquisition (EUS-TA) in patients on uninterrupted antithrombotic agents is unknown. This study aimed to assess the safety of EUS-TA without discontinuing direct oral anticoagulants. Methods Twenty pigs were randomized (1:1) to oral apixaban or placebo. Treatment was administered for 3 days before and 3 days after EUS-TA of the pancreas. Primary endpoint was occurrence of clinically significant bleeding events (CSBEs), defined as a composite outcome of drop in hemoglobin ≥ 2 g/dL and evidence of intraprocedural or post-procedure bleeding. Secondary outcome was cytopathological adequacy of acquired specimens. Endoscopists and pathologists were blinded to the treatment arm. Results Total of 80 tissue samples were obtained. CSBE occurred in one animal with apixaban levels above the upper limit (P = 1). Intraprocedural bleeding occurred in five animals (25 %), four of which from the apixaban group. Hematoma at necropsy was found in 10 animals (50 %), six of which were on apixaban. Median drop in hemoglobin was similar in both groups. Adequacy of specimens for cytology and pathology evaluation was confirmed in 20 of 20 and 19 of 20 animals, respectively. Conclusions In this pilot preclinical trial, EUS-TA under apixaban showed a trend toward higher minor bleeding events but did not increase CSBE or prevent adequate cytopathological evaluation.

Abstract Purpose: The purpose of this study was to evaluate the feasibility and specimen quality of lymph node biopsies prepared through a novel automated system for automated fixation, drying and staining compared to standard slide preparation method. Methods: We performed a prospective, single-center study of patients undergoing endobronchial ultrasound. Samples were split into conventional standard of care (SOC) slide preparation and preparation using the device (ASP). Pathologists compared the SOC slides to the slides prepared by the automated system and assessed the following metrics: nuclear and cytoplasmic quality, presence of debris/artifact, staining quality, creation of a monolayer, and ease of adequacy/diagnosis assessment. A score between 1 (lowest quality) and 3 (highest quality) was assigned to the above metrics. Results: 60 patients were recruited. One to three lymph nodes were sampled for each patient with a total of 73 samples collected. The mean scores of each assessment category showed no statistical difference between the two preparation techniques except for improved monolayer creation in the ASP samples. All samples showed diagnostic equivalency between the automated slides and conventional slides except for one which was reported to be suspicious on the ASP sample and atypical on the SOC. Conclusion: Study results suggest that slides prepared by the automated system are of adequate quality for adequacy assessment with diagnostic concordance when compared to SOC slides.

Abstract Introduction: The incidence of esophageal adenocarcinoma (EAC) has increased more than any other cancer in our lifetime. Barrett’s esophagus (BE) is the only known precursor to EAC. At present, HER-2 and anti-PD-L1 therapies are FDA-approved for EAC, and off-label use of EGFR-directed therapy has been reported. Our study aims to use liquid chromatography mass spectrometry (LC/MS) to measure the expression of oncoproteins that are currently approved-drug targets in EAC and explore new promising targets for drug development and diagnostic applications for EAC and BE. Methods: EAC patients who underwent esophagectomy without chemo-radiation were identified. BE patients with subsequent progression to EAC and those without progression for &gt;10 years were identified. Normal esophageal mucosa tissues with no history of progression were analyzed for baseline expression. Tissue sections were microdissected to isolate pure EAC, BE and normal mucosal cells from stroma. These biopsies were solubilized for LC/MS-based quantification of 80+ clinically relevant tumor markers including novel markers which are believed to play a role in the disease progression from BE to EAC. The expression trends of these markers were scrutinized by immunofluorescence (IF) in a subset of specimens/biomarkers to confirm mass spec results. Results: A total of 159 tissues were analyzed via LC-MS. In 55 EAC tissues - HER2, PD-L1 and EGFR were overexpressed in 16.3%, 0%, and 0% of patients, respectively. New markers DAD1 and S100P were noted to have high (7,634.0 and 27,222.6 attomoles/ug) and consistent (98.1% and 94.5%) overexpression in EAC samples. Expression of HER2, S100P and DAD1 were significantly higher in EAC compared to 23 normal esophageal mucosa specimens. There was no statistical difference in the expression of PD-L1 and EGFR between EAC and healthy mucosal samples. 45 BE biopsies progressed to EAC within a mean of 380 days, while the remaining 36 BE specimens did not progress over a 10-year period. 8 novel biomarkers were expressed at a higher level in BE tissue that progressed to cancer when compared to esophageal tissue that remained stable over 10 years. The expression trends observed via LC/MS were confirmed via IF in DAD1, S100P and two other novel markers. Discussion: LC-MS revealed low prevalence of target proteins in currently approved EAC therapies and high levels of newly discovered disease drivers that should be explored as possible therapy targets or diagnostic markers. The differential overexpression of the novel markers in progressive and non-progressive BE tissues, as well as the consistent overexpression of these markers in EAC tumors, demonstrates the potential for early detection of esophageal carcinogenesis and/or reveals potential therapeutic programs for an indication that lacks highly efficacious targeted therapy options. Citation Format: Christopher Hartley, Ajay Bansal, Catherine Hagen, Olivia Driscoll, Seyun Oh, Joe Abdo, Sumeet K. Mittal. Mass spectrometry detects lower frequency of routine markers and consistent overexpression of novel disease drivers in Barrett's-related esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2805.

The published literature on cervicovaginal cytology includes fewer than ten reported cases of Cokeromyces recurvatus identified in Pap test samples. We report a unique case of an asymptomatic 27-year-old female with persistent gynecologic tract colonization by C. recurvatus in which distinctive fungal microorganisms were identified in three samples collected over three consecutive years.