Faculty Bibliography

Myeloid sarcoma, an aggressive extramedullary subtype of acute myeloid leukemia (AML), occurs in approximately 20% of patients, and remains strikingly understudied in large-scale genomic and multiomic investigations. The key drivers of its tumor evolution are largely unknown, timely detection in asymptomatic patients poses a clinical challenge, and effective treatment options are limited as patients are often excluded from clinical trials, rendering it a largely neglected disease entity. Here, we demonstrate that myeloid sarcoma evolves from medullary AML but exhibits distinct site-specific clonal evolution. This is supported by unique transcriptional signatures of myeloid sarcoma, reflecting adaptation to the extramedullary microenvironment. We establish a proof of concept that circulating tumor DNA sequencing captures the molecular composition of myeloid sarcoma, offering a potential non-invasive approach for molecular profiling of extramedullary AML. Our findings highlight marked differences between medullary AML and myeloid sarcoma, including universal molecular evolution and RAS pathway activation as disease hallmarks.

BACKGROUND & AIMS/OBJECTIVE:Hepatocellular carcinoma (HCC) is the third deadliest cancer worldwide. Over 75% of HCC cases are associated with chronic viral infections. Mechanistic studies and preclinical therapeutic development for virus-associated HCC have been limited by a paucity of small animal models of chronic hepatotropic virus infection that faithfully recapitulate human disease. METHODS AND RESULTS/RESULTS:Here we demonstrate the induction of chronic hepatitis, progressive liver fibrosis, and HCC in immunocompetent laboratory mice upon chronic viral infection with Norway rat hepacivirus (NrHV) - a virus closely related to hepatitis C virus (HCV). NrHV-elicited tumors resemble HCV-associated tumors and liver transcriptome analyses reveal numerous similarities between chronic NrHV and HCV. CONCLUSIONS:These findings establish an experimentally tractable, physiologically relevant, and immunocompetent mouse model of virus-elicited progressive liver fibrosis and oncogenesis. IMPACT AND IMPLICATIONS: (lay summary); The NrHV-HCC model represents the first immunocompetent infectious system that faithfully recapitulates the multistage progression from chronic viral hepatitis to spontaneous hepatocellular carcinoma, bridging a long-standing translational gap between mechanistic mouse studies and human liver cancer. By mirroring the immunopathological, molecular, and sex-associated features of chronic HCV infection, this model provides an unparalleled platform to investigate virus-host interactions underlying fibrosis and oncogenesis. High HCC penetrance and the genetically tractable C57BL/6 background further enhance experimental utility, enabling precise mechanistic dissection and genetic manipulation in a physiologically relevant setting. The capacity to study spontaneous tumor development in the context of natural infection allows for rigorous testing of antifibrotic and anti-cancer strategies, while the persistence of oncogenic potential after viral clearance raises important questions about irreversible disease reprogramming and elevated cancer risk following viral cure - issues of direct relevance to patients cured of HCV.

OBJECTIVES/OBJECTIVE:With the development of genomic technologies, the isolation of genomic DNA (gDNA) from clinical samples has become more important for both clinical diagnostics and research studies. Blood samples collected in PAXgene Blood RNA Tubes, which are typically used for RNA extraction, can be used for gDNA extraction, particularly in clinical studies when only such blood samples are available. METHODS:We optimized the pre-treatment of blood samples collected in PAXgene Blood RNA Tubes. For the first time, three magnetic bead-based automated platforms (QIAsymphony SP, Maxwell RSC and KingFisher Apex) were compared for gDNA extraction from these blood samples. Additionally, the effects of storage at 4 °C or freeze-thaw cycles of the blood samples on gDNA yield were investigated. High-throughput extraction in 96-well format was evaluated. RESULTS:Systematic optimization of blood sample pre-treatment shows that prolonged incubation at room temperature and/or increased centrifugation speed and time improved gDNA yield from blood samples collected in PAXgene Blood RNA Tubes. QIAsymphony SP (4.27 ± 2.19 µg) and Maxwell RSC (4.82 ± 2.96 µg) produced significantly higher gDNA yields than KingFisher Apex (1.09 ± 0.61 µg). Higher gDNA yields were obtained with shorter storage time at 4 °C or fewer freeze-thaw cycles of the blood samples. In the 96-well format extraction, gDNA yields ranged from 0.24 to 13.46 µg. CONCLUSIONS:Not all magnetic bead-based automated platforms are suitable for gDNA extraction from blood samples collected in PAXgene Blood RNA Tubes. Systematic pre-treatments optimization provides guidance for routine and high-throughput workflows, and storage conditions and freeze-thaw cycles offer practical reference for biobanking.

BACKGROUND AND AIMS/UNASSIGNED:Hepatocyte steatosis in metabolic dysfunction-associated steatotic liver disease can change quickly based on the types and amounts of calories consumed. This study investigates how dietary changes affect steatosis resolution in human hepatocytes and whether patatin-like phospholipase domain-containing 3 (PNPLA3) genetic variants influence this process. METHODS/UNASSIGNED:) hepatocytes were fed a Western diet (WD) and/or 10% sucrose water (10%S) to induce steatosis. After 4 weeks, mice either resumed chow to promote steatosis resolution or continued on WD or 10%S. RESULTS/UNASSIGNED:livers, including the retention of many polyunsaturated phosphatidylethanolamines and long-chain diglycerides. CONCLUSION/UNASSIGNED:PNPLA3 3 148-isoleucine variant human hepatocytes in chimeric mice rapidly resolve steatosis with a gradual improvement in steatohepatitis activity, which is delayed in PNPLA3-148M hepatocytes. This supports a model in which altered lipid mobilization in PNPLA3-148M hepatocytes contributes to more active steatohepatitis.

BACKGROUND:The introduction of Trastuzumab deruxtecan (T-Dxd) has exposed clinically significant limitations in accurately detecting HER2-low expression testing when using immunohistochemistry (IHC) assays originally developed to detect HER2 over-expression. While HER2 testing is widely used to determine T-Dxd eligibility, no HER2-low assay was ever validated against HER2 protein expression. METHODS:To address this pressing need, the Consortium for Analytic Standardization in Immunohistochemistry (CASI) conducted the CASI-01 study, involving 54 IHC laboratories across Europe and the U.S. The study aimed to identify optimal assay conditions for accurate HER2 testing, differentiating between HER2 overexpression (3+) for Trastuzumab eligibility and HER2-low expression (1+ or ultra-low) for T-Dxd eligibility. The conventional FDA-cleared HER2 assay ("predicate") was compared with higher-sensitivity assays using pathologist versus image analysis readouts. HER2 overexpression was validated against HER2 gene amplification via in situ hybridisation (ISH), while HER2-low accuracy was evaluated using newly introduced HER2 reference standards and a novel IHC parameter-dynamic range. FINDINGS/RESULTS:CASI-01 revealed variability in predicate HER2 assays, with detection thresholds ranging from 30,000 to 60,000 among laboratories. Despite this variability, these assays demonstrated high accuracy for identifying HER2 overexpression (3+), with 85.7% (18/21) sensitivity (95% confidence limits 63.66-96.95%) and 100% (49/49) specificity (95% confidence limits 92.75-100%), though sensitivity may have been limited by the use of older tissue specimens, with loss or reduced expression levels of the HER2 protein. However, these same assays exhibited poor dynamic range for detecting HER2-low scores. Enhanced analytic sensitivity of IHC assays combined with image analysis overcame this limitation with HER2-low scores, achieving a six-fold improvement (p = 0.0017). INTERPRETATION/CONCLUSIONS:IHC assays with detection thresholds in the range of 30,000-60,000 HER2 molecules per cell yield accurate results for determination of Trastuzumab eligibility (HER2 3+) but fail to demonstrate the dynamic range for accurate HER2-low scores. Enhanced analytic sensitivity of HER2 assays combined with image analysis addresses this critical gap in HER2-low testing. More generally, CASI-01 introduces pivotal advancements in precision medicine: (a) the importance of reporting IHC analytic sensitivity and ability to demonstrate an assay dynamic range, and (b) image analysis can surpass pathologist readout accuracy in specific clinical contexts. FUNDING/BACKGROUND:This work was supported by the National Cancer Institute of the National Institutes of Health under Award Number R44CA268484.

Bodies have continuous reticular networks, comprising collagens and other extracellular matrix components, through all tissues and organs. We recently validated fluid flow through human interstitium and demonstrated that they are filled with hyaluronic acid by staining with biotinylated hyaluronic acid binding protein. Their continuity across tissue boundaries (skin and subcutis), and between organs (colon and mesentery) and along vessels (within adventitia) and nerves (within perineurium) has been demonstrated in this manner. We aim to evaluate the continuity of interstitium within human pancreas and beyond into adjoining tissues. Tissue blocks of histologically normal pancreas from nine pancreatectomy specimens were sectioned in parallel for staining with hematoxylin and eosin, Picrosirius red, and biotinylated hyaluronic acid binding protein. Also, specimens of invasive pancreatic cancer were assessed for interstitial tumor invasion. Picrosirius red ensheathes all microscopic units of the endocrine and exocrine pancreas, including acini, islets, and ducts, adventitia of blood vessels and perineurium, and into adjacent duodenum. Interstitial spaces within the fibrous tissue are filled with hyaluronic acid by staining and are also continuous through all microscopic structures of the pancreas, into adjoining duodenum and along vessels (within adventitia) and nerves (within perineurium). Invasive carcinoma is seen spreading through pre-existing interstitial spaces. Interstitium of the human pancreas is continuous within and beyond the pancreas. This continuity suggests the capacity to be a route of molecular, microbiome, and cellular trafficking and communication. In particular, it is a route of cancer spread.

There is a body-wide network of interstitial spaces that includes three components: a large-scale fascial network made up of fluid-filled spaces containing collagens and other extracellular matrix components like hyaluronic acid (HA), the peri-vascular/capillary interstitium, and intercellular interstitial spaces. Staining for HA within the colon, skin, and liver has demonstrated spatial continuity of the fascial interstitium across tissue layers and between organs, while continuity of HA staining between perineurial and adventitial sheathes beyond organ boundaries confirmed that they also participate in this body-wide network. We asked whether the pulmonary interstitium comprises a continuous organ-wide network that also connects to the body-wide interstitium via routes along nerves and the vasculature. We studied archival lung lobectomy specimens containing normal tissues inclusive of all lung anatomical units from six females and three males (mean age 53+/- 16.5 years). For comparison, we also studied normal mouse lung. Multiplex immunohistochemical cocktails were used to identify: (1) HA, CD34, and vimentin - highlighting interstitium; (2) HA, CD34, and podoplanin (D2-40) - highlighting relationships between the interstitium, vasculature, and lymphatics. Sizes of extracellular APP were measured. Tissues from nine patients (six females, three males, mean age 53+/- 16.5 years) were studied. HA staining was continuous throughout the five major anatomic compartments of the lung: alveolar walls, subpleural connective tissue, centrilobular peribronchovascular compartment, interlobular septal compartment, and axial peribronchovascular of the hilum, with similar findings in murine lung tissue. Continuity with interstitial spaces of the perineurium and adventitia was confirmed. The distribution of APP corresponded to known routes of lymphatic drainage, superficial and deep. APP within perineurium and perivascular adventitia further demonstrated continuity between intra- and extrapulmonary interstitium. To conclude, all segments of the lung interstitium are connected and are linked along nerves and the vascular tree to a body-wide communication network. These findings have significant implications for understanding lung physiology and pathobiology, suggesting routes of passage for inflammatory cells and mediators, malignant cells, and infectious agents. Interstitial spaces may be important in microbiome signaling within and beyond the lung and may be a component of the lung-brain axis.

BACKGROUND:Digital papillary adenocarcinoma (DPAC) is a rare but aggressive cutaneous malignant sweat gland neoplasm that occurs on acral sites. Despite its clinical significance, the cellular and genetic characteristics of DPAC remain incompletely understood. METHODS:We conducted a comprehensive genomic and transcriptomic analysis of DPAC (n = 14) using targeted next-generation DNA and RNA sequencing, along with gene expression profiling employing the Nanostring Technologies nCounter IO 360 Panel. Gene expression in DPAC was compared to that in hidradenoma (n = 10). Immunohistochemistry was employed to validate gene expression. RESULTS:Two out of eight DPACs showed fusion gene rearrangements (CRTC3::MAML2 and TRPS1::PLAG1). No uniform mutational signature was detected in DPAC. Comparative gene expression analysis revealed an enrichment of genes related to matrix remodeling, metabolism, and DNA damage repair. Hallmark pathway analysis demonstrated significant upregulation of E2F target genes in DPAC compared to hidradenoma (p = 0.00710). Human papillomavirus-42 was found to be positive in all of our tested DPAC cases. Immunohistochemistry confirmed increased protein expression of CD56, CDC20, and SOX10 in DPAC. Notably, most DPAC tumors also exhibited B-cell infiltration, as indicated by CD20 staining. CONCLUSIONS:Our findings reveal novel fusions and validate altered replication pathways related to HPV42 in DPAC.

Over the last decade, Hippo signaling has emerged as a major tumor-suppressing pathway. Its dysregulation is associated with abnormal expression of YAP1 and TEAD-family genes. Recent works have highlighted the role of YAP1/TEAD activity in several cancers and its potential therapeutic implications. Therefore, identifying patients with a dysregulated Hippo pathway is key to enhancing treatment impact. Although recent studies have derived RNA-seq-based signatures, there remains a need for a reproducible and cost-effective method to measure the pathway activation. In recent years, deep learning applied to histology slides have emerged as an effective way to predict molecular information from a data modality available in clinical routine. Here, we trained models to predict YAP1/TEAD activity from H&E-stained histology slides in multiple cancers. The robustness of our approach was assessed in seven independent validation cohorts. Finally, we showed that histological markers of disease aggressiveness were associated with dysfunctional Hippo signaling.

BACKGROUND:Dickkopf-related protein 1 (DKK1) is a Wingless-related integrate site (Wnt) signaling modulator that is upregulated in prostate cancers (PCa) with low androgen receptor expression. DKN-01, an IgG4 that neutralizes DKK1, delays PCa growth in pre-clinical DKK1-expressing models. These data provided the rationale for a clinical trial testing DKN-01 in patients with metastatic castration-resistant PCa (mCRPC). METHODS:(combination) for men with mCRPC who progressed on ≥1 AR signaling inhibitors. DKK1 status was determined by RNA in-situ expression. The primary endpoint of the phase 1 dose escalation cohorts was the determination of the recommended phase 2 dose (RP2D). The primary endpoint of the phase 2 expansion cohorts was objective response rate by iRECIST criteria in patients treated with the combination. RESULTS:18 pts were enrolled into the study-10 patients in the monotherapy cohorts and 8 patients in the combination cohorts. No DLTs were observed and DKN-01 600 mg was determined as the RP2D. A best overall response of stable disease occurred in two out of seven (29%) evaluable patients in the monotherapy cohort. In the combination cohort, five out of seven (71%) evaluable patients had a partial response (PR). A median rPFS of 5.7 months was observed in the combination cohort. In the combination cohort, the median tumoral DKK1 expression H-score was 0.75 and the rPFS observed was similar between patients with DKK1 H-score ≥1 versus H-score = 0. CONCLUSION/CONCLUSIONS:DKN-01 600 mg was well tolerated. DKK1 blockade has modest anti-tumor activity as a monotherapy for mCRPC. Anti-tumor activity was observed in the combination cohorts, but the response duration was limited. DKK1 expression in the majority of mCRPC is low and did not clearly correlate with anti-tumor activity of DKN-01 plus docetaxel.