This study introduces a new imaging, spatial transcriptomics (ST), and single-cell RNA-sequencing integration pipeline to characterize neoplastic cell state transitions during tumorigenesis. We applied a semi-supervised analysis pipeline to examine premalignant pancreatic intraepithelial neoplasias (PanINs) that can develop into pancreatic ductal adenocarcinoma (PDAC). Their strict diagnosis on formalin-fixed and paraffin-embedded (FFPE) samples limited the single-cell characterization of human PanINs within their microenvironment. We leverage whole transcriptome FFPE ST to enable the study of a rare cohort of matched low-grade (LG) and high-grade (HG) PanIN lesions to track progression and map cellular phenotypes relative to single-cell PDAC datasets. We demonstrate that cancer-associated fibroblasts (CAFs), including antigen-presenting CAFs, are located close to PanINs. We further observed a transition from CAF-related inflammatory signaling to cellular proliferation during PanIN progression. We validate these findings with single-cell high-dimensional imaging proteomics and transcriptomics technologies. Altogether, our semi-supervised learning framework for spatial multi-omics has broad applicability across cancer types to decipher the spatiotemporal dynamics of carcinogenesis.

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive form of cancer with a low survival rate. A successful treatment strategy should not be limited to targeting cancer cells alone, but should adopt a more comprehensive approach, taking into account other influential factors. These include the extracellular matrix (ECM) and immune microenvironment, both of which are integral components of the tumor microenvironment. The present review describes the roles of pancreatic stellate cells, differentiated cancer‑associated fibroblasts and the interleukin family, either independently or in combination, in the progression of precursor lesions in pancreatic intraepithelial neoplasia and PDAC. These elements contribute to ECM deposition and immunosuppression in PDAC. Therapeutic strategies that integrate interleukin and/or stromal blockade for PDAC immunomodulation and fibrogenesis have yielded inconsistent results. A deeper comprehension of the intricate interplay between fibrosis, and immune responses could pave the way for more effective treatment targets, by elucidating the mechanisms and causes of ECM fibrosis during PDAC progression.

Pancreatic carcinoma is a relatively common malignant tumor with increasing incidence and mortality. The tumor is usually diagnosed at an advanced stage and generally has a poor prognosis, with only 5% of patients surviving 5 years from the time of diagnosis. The stage of the disease at the time of diagnosis is a crucial factor for the prognosis; 25% of patients with localized tumors survive 3 years from diagnosis, compared to only 1% of those with generalized tumors. Radical surgical removal of the tumor (partial or total pancreatectomy) is a key factor in improving survival. Therefore, the topic is highly relevant to surgeons. Statistics on pancreatic carcinoma mainly focus on ductal adenocarcinoma, which is the most common and least favorable malignant tumor of the pancreas. This review focuses on ductal adenocarcinoma, its variants, and precancerous lesions. The article summarizes information from the latest WHO classification of 2019, which was released 11 years after the previous edition. Compared to the previous version, this new WHO classification introduced rather minor changes in the field of ductal adenocarcinoma. The delineation of rare variants of ductal adenocarcinoma is justified based on genetic and morphological similarities and clinical relevance, as individual subtypes significantly differ in prognosis. The article also includes a description of macroscopic and microscopic precursors of ductal adenocarcinoma and their definitions. Genetic and immunohistochemical differential diagnostic aspects are briefly discussed, as these are more relevant to pathologists than to surgeons.

Pancreatic surveillance can detect early-stage pancreatic cancer and achieve long-term survival, but currently involves annual endoscopic ultrasound and MRI/MRCP, and is recommended only for individuals who meet familial/genetic risk criteria. To improve upon current approaches to pancreatic cancer early detection and to expand access, more accurate, inexpensive, and safe biomarkers are needed, but finding them has remained elusive. Newer approaches to early detection, such as using gene tests to personalize biomarker interpretation, and the increasing application of artificial intelligence approaches to integrate complex biomarker data, offer promise that clinically useful biomarkers for early pancreatic cancer detection are on the horizon.

Synchronous primary neoplasms of Meckel\'s diverticulum and colon malignancies are rarely reported in the literature. We present three patients with synchronous primary neoplasms of Meckel\'s diverticulum and colon malignancies. All tumors located in Meckel\'s diverticulum were incidentally found at laparotomy and the definitive diagnosis was made with microscopic examination of surgical specimens. Synchronous primary neoplasms of Meckel\'s diverticulum and colon malignancies are rarely encountered. Moreover, this is the first case of synchronous colon cancer and pancreatic intraepithelial neoplasia (PanIN) arising from pancreatic heterotopia within Meckel\'s diverticulum. The diagnosis of Meckel\'s diverticulum should be kept in mind in patients who underwent laparotomy for any reason; when found incidentally at laparotomy, it should be carefully examined for any suspicious abnormality and surgery should be considered that it can be performed without any problems.

In the early years of my GI fellowship, a healthy 40-year-old man came to my clinic and announced that he was going to die of pancreatic cancer. His brothers, father and uncles had all died of the disease; he felt his fate was inescapable. I asked whether his family members had seen doctors or had any tests. His answer was yes to both. Even so, doctors could not diagnose the pancreatic cancer at early stages. CT scans were always negative. I thought to myself, in order to help this patient-CT scans may not be reliable for early detection. Perhaps other methods of imaging the pancreas might be of more benefit. This patient opened a door that led to a 30-year journey of trying to detect pancreatic cancer at earlier stages when it is curable.

Pancreatic ductal adenocarcinoma (PDAC) is a tumor with a dismal prognosis that arises from precursor lesions called pancreatic intraepithelial neoplasias (PanINs). Progression from low- to high-grade PanINs is considered as tumor initiation, and a deeper understanding of this switch is needed. Here, we show that synaptic molecule neuroligin-2 (NLGN2) is expressed by pancreatic exocrine cells and plays a crucial role in the regulation of contact inhibition and epithelial polarity, which characterize the switch from low- to high-grade PanIN. NLGN2 localizes to tight junctions in acinar cells, is diffusely distributed in the cytosol in low-grade PanINs and is lost in high-grade PanINs and in a high percentage of advanced PDACs. Mechanistically, NLGN2 is necessary for the formation of the PALS1/PATJ complex, which in turn induces contact inhibition by reducing YAP function. Our results provide novel insights into NLGN2 functions outside the nervous system and can be used to model PanIN progression.

MAP4K4 is a serine/threonine kinase of the STE20 family involved in the regulation of actin cytoskeleton dynamics and cell motility. It has been proposed as a target of angiogenesis and inhibitors show potential in cardioprotection. MAP4K4 also mediates cell invasion in vitro, is overexpressed in various types of cancer, and is associated with poor patient prognosis. Recently, MAP4K4 has been shown to be overexpressed in pancreatic cancer, but its role in tumour initiation, progression, and metastasis is unknown. Here, using the KrasG12D Trp53R172H Pdx1-Cre (KPC) mouse model of pancreatic ductal adenocarcinoma (PDAC), we show that deletion of Map4k4 drives tumour initiation and progression. Moreover, we report that the acceleration of tumour onset is also associated with an overactivation of ERK and AKT, two major downstream effectors of KRAS, in vitro and in vivo. In contrast to the accelerated tumour onset caused by loss of MAP4K4, we observed a reduction in metastatic burden with both the KPC model and in an intraperitoneal transplant assay indicating a major role of MAP4K4 in metastatic seeding. In summary, our study sheds light on the dichotomous role of MAP4K4 in the initiation of PDAC onset, progression, and metastatic dissemination. It also identifies MAP4K4 as a possible druggable target against pancreatic cancer spread, but with the caveat that targeting MAP4K4 might accelerate early tumorigenesis. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pancreatic intraepithelial neoplasia (PanIN) is the most common precursor lesion that has the potential to progress to invasive pancreatic cancer, and early and rapid detection may offer patients a chance for treatment before the development of invasive carcinoma. Therefore, the identification of PanIN holds significant clinical importance. In this study, we first used multiphoton microscopy (MPM) combining two-photon excitation fluorescence and second-harmonic generation imaging to label-free detect PanIN and attempted to differentiate between normal pancreatic ducts and different grades of PanIN. Then, we also developed an automatic image processing strategy to extract eight morphological features of collagen fibers from MPM images to quantify the changes in collagen fibers surrounding the ducts. Experimental results demonstrate that the combination of MPM and quantitative information can accurately identify normal pancreatic ducts and different grades of PanIN. This study may contribute to the rapid diagnosis of pancreatic diseases and may lay the foundation for further clinical application of MPM.

BACKGROUND: Shuangshen granules (SSG), a nationally patented Chinese medicinal formula, including Panax quinquefolium L., Panax notoginseng (Burkill) F. H. Chen, and Cordyceps sinensis (Berk.) Sacc., has demonstrated remarkable therapeutic effects on pancreatic cancer in clinical treatment for nearly 10 years. Previous pharmacological researches have found that its main components, including ginsenosides and cordycepin have anticancer or preventive effects on pancreatic ductal adenocarcinoma (PDAC), which may be associated with immune metabolism. However, the underlying pharmacological mechanism of SSG in the truncation effect of PDAC progression is still unclear.
OBJECTIVE: To comprehensively understand the infiltrating immune cells during the different stages of the PDAC development chain and search for immune-related biomarkers that could potentially serve as drug targets through bioinformatic analysis. Meanwhile, the truncation effect of SSG on PDAC progression was also investigated.
METHODS: The gene expression profiles at different PDAC developmental stages, including normal pancreas, pancreatic intraepithelial neoplasia (PanIN), and PDAC, were retrieved from the GEO database. The GEO2R tool was used to identify differentially expressed genes among the three groups. Functional enrichment analysis was performed with the GSEA software and Metascape platform. The CIBERSORT algorithm evaluated immune cell infiltration in the three groups, and immune-related biomarkers were identified. Correlation analysis was employed to examine the association between immune cells and the biomarkers. One of these biomarkers was selected for immunohistochemistry validation in human samples. Lastly, the effectiveness of SSG against PDAC progression and the influence on the selected biomarker were validated in vivo. The underlying pharmacological mechanisms were also explored.
RESULTS: One dataset was obtained, where the functional enrichment of DEGs primarily involved immune effector processes and cytokine production of immune cells. The differential immune cells reflected during the progression from PanIN to PDAC were B memory cells, monocytes, M2 macrophages, and activated dendritic cells. The upregulation of ACTA2 was closely associated with M2 macrophage regulation. The immunohistochemistry on human samples validated significant differences in ACTA2 expression levels as the PDAC progressed. Moreover, animal experiments revealed that the national patented drug SSG ameliorated the pathological changes, decreased the expression of ACTA2 and its functional protein α-smooth muscle actin during PDAC progression. The underlying pharmacological mechanism was related to the regulation of macrophage polarization and downregulation of TGF-β/Smad signaling pathway.
CONCLUSIONS: The immunosuppressive environment changes during the PDAC progression. ACTA2 is a potential immuned-target for drug prevention of PDAC, while SSG could be a promising drug candidate.