Recurrent GNAS mutations define an unexpected pathway for pancreatic cyst development

Molecular and immunohistochemical markers in appendiceal mucinous neoplasms: A systematic review and comparative analysis with ovarian mucinous neoplasms and colorectal adenocarcinoma

INTRODUCTION

Appendiceal mucinous neoplasms (AMNs) represent a rare and diagnostically challenging group of tumors. This systematic review aims to summarize the reported molecular and immunohistochemical markers (IHC) associated with AMNs and compare them with ovarian mucinous neoplasms (OMNs) and colorectal adenocarcinoma (CRC).

METHODS

A comprehensive search was performed in PubMed/MEDLINE/PMC, Scopus, Embase, and Web of Science databases to identify studies looking at IHC and molecular markers in AMNs. Chi-squared and Fisher's exact tests were utilized to compare the marker expression across different tumor types.

RESULTS

We identified 27 articles reporting several potential biomarkers for distinguishing between different subtypes of AMNs. Mutations in KRAS, GNAS, and RNF43 emerged as notable biomarkers, with KRAS mutations being the most prevalent across all subtypes. Additionally, p53 IHC overexpression was associated with higher tumor grades. When comparing AMNs with OMNs, we observed a higher prevalence of CK20, CDX2, SATB2, and MUC2 IHC expression, as well as KRAS and GNAS mutations, in AMNs. Conversely, CK7 and PAX8 IHC expression were more prevalent in OMNs. Comparing AMNs with CRCs, we found a higher prevalence of TOPO1 and PTEN IHC expression, as well as KRAS and GNAS mutations, in AMNs. Conversely, nuclear β-catenin IHC expression, as well as TP53, APC, and PIK3CA mutations, were more prevalent in CRCs.

CONCLUSION

This systematic review identified possible markers for distinguishing AMNs and differentiating between AMNs, OMNs, or CRCs.

Contract to kill: GNAS mutation

The mutation in Gsα-coding GNAS exons, popular as gsp oncogene, is the most frequent mutation across all heterotrimeric G proteins involved in oncogenesis. GNAS R201, the most frequently mutated, followed by Q227, are found predominantly across various neoplasms and cancers such as IPMN, pituitary, thyroid, appendiceal, colorectal, etc. This review emphasizes the pivotal significance of the gsp oncogene and its ramifications underpinning the sustained addiction to GNAS mutation. Recent studies delineating the mechanistic intricacies that provide solid evidence of the profound impact of oncogenic GNAS on tumor formation, progression, and maintenance are highlighted. We have leveraged the discoveries of Gsα as an ideal neoantigen candidate for vaccine therapy, allele-specific inhibitors, and cyclic peptide-based small molecular inhibitors for G proteins and explored the therapeutic potential to target oncogenic GNAS directly. Alternative therapeutic modalities and patient-centric studies to mitigate the impact of GNAS mutations are also discussed. The exposition of novel studies and strategies designed to address the potential challenges inherent in these approaches of targeting the activating mutations of GNAS, along with probable avenues for further investigation, are highlighted. This review aims to reverberate the current understanding of the oncogenic potential of GNAS, the genomic and biological landscape of GNAS-driven neoplasms and cancers, and potential therapeutic strategies against them.

Correlation of GNAS Mutational Status with Oncologic Outcomes in Patients with Resected Intraductal Papillary Mucinous Neoplasms

Background: Intraductal papillary mucinous neoplasms (IPMNs) are pre-malignant pancreatic lesions that may progress to invasive pancreatic ductal adenocarcinoma (PDAC). IPMN-associated invasive carcinoma (iIPMN) has been associated with more favorable survival outcomes compared to non-iIPMN-derived PDAC. Here, we aim to investigate the genetic landscape of IPMNs to assess their relevance to oncologic outcomes. Methods: This retrospective study used a large single-institution prospectively maintained database. Patients who underwent curative-intent pancreatic resection between 2016 and 2022 with histologically confirmed diagnosis of IPMN were included. Demographic, pathologic, molecular, and oncologic outcome data were recorded. Kaplan-Meier survival analyses were performed. PDAC data from public genetic databases were used for mutational correlation analysis. p-value ≤ 0.05 was considered as significant. Results: A total of thirty-nine patients with resected IPMN with complete clinical and sequencing data were identified and included in the final cohort. The male-to-female distribution was 21:18, and the mean age was 70.1 ± 9.1 years. GNAS mutations occurred in 23.1% of patients, and 89.7% of patients had iIPMN. In iIPMN patients, GNAS mutation was strongly associated with improved disease-free survival: all GNAS-mutant patients survived to follow-up with significantly fewer recurrences than in GNAS wild-type (WT) patients (p = 0.013). Mutated GNAS closely co-occurred with wild-type KRAS (p < 0.001), and further analysis of large genomic PDAC datasets validated this finding (OR 3.47, p < 0.0001). Conclusions: Our study suggests prognostic value of mutational status in malignant resected IPMNs. WT GNAS, mutant P53, and mutant KRAS each correlate with recurrence and decreased survival. Further studies are required to validate these preliminary observations.

Multi-omic markers of intraductal papillary mucinous neoplasms progression into pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal and common form of pancreatic cancer, it has no specific symptoms, and most of the patients are diagnosed when the disease is already at an advanced stage. Chemotherapy typically has only a modest effect, making surgery the most effective treatment option. However, only a small percentage of patients are amenable to surgery. One viable strategy to reduce PDAC death burden associated with the disease is to focus on precursor lesions and identify markers able to predict who will evolve into PDAC. While most PDACs are believed to be preceded by pancreatic intraepithelial neoplasms (PanINs), 5-10 % arise from Intraductal papillary mucinous neoplasms (IPMNs), which are mass-forming cystic lesions that are very common in the general population. IPMNs offer an invaluable model of pancreatic carcinogenesis for researchers to analyse, as well as a target population for PDAC early detection by clinicians. The evolution of IPMN into cancer is a complex and multistep process, therefore the identification of individual markers will not be the solution. In recent years, multiple omics technologies have been instrumental to identify possible biomarkers of IPMN progression and carcinogenesis. The only foreseeable strategy will be to integrate multi-omics data, alongside clinical and morphological features, into a progression score or signature using either standard epidemiologic tools or artificial intelligence. The aim of this manuscript is to review the current knowledge on genetic biomarkers and to briefly mention also additional omics, such as metabolomics, the exposome, the miRNome and epigenomics of IPMNs.

Genetics and biology of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) poses a grim prognosis for patients. Recent multidisciplinary research efforts have provided critical insights into its genetics and tumor biology, creating the foundation for rational development of targeted and immune therapies. Here, we review the PDAC genomic landscape and the role of specific oncogenic events in tumor initiation and progression, as well as their contributions to shaping its tumor biology. We further summarize and synthesize breakthroughs in single-cell and metabolic profiling technologies that have illuminated the complex cellular composition and heterotypic interactions of the PDAC tumor microenvironment, with an emphasis on metabolic cross-talk across cancer and stromal cells that sustains anabolic growth and suppresses tumor immunity. These conceptual advances have generated novel immunotherapy regimens, particularly cancer vaccines, which are now in clinical testing. We also highlight the advent of KRAS targeted therapy, a milestone advance that has transformed treatment paradigms and offers a platform for combined immunotherapy and targeted strategies. This review provides a perspective summarizing current scientific and therapeutic challenges as well as practice-changing opportunities for the PDAC field at this major inflection point.

Functionalized Nanomaterials In Pancreatic Cancer Theranostics And Molecular Imaging

Pancreatic cancer (PC) is one of the most fatal malignancies in the world. This lethality persists due to lack of effective and efficient treatment strategies. Pancreatic ductal adenocarcinoma (PDAC) is an aggressive epithelial malignancy which has a high incidence rate and contributes to overall cancer fatalities. As of 2022, pancreatic cancer contributes to about 3 % of all cancers globally. Over the years, research has characterised germline predisposition, the origin cell, precursor lesions, genetic alterations, structural alterations, transcriptional changes, tumour heterogeneity, metastatic progression, and the tumour microenvironment, which has improved the understanding of PDAC carcinogenesis. By using molecular-based target therapies, these fundamental advancements support primary prevention, screening, early detection, and treatment. The focus of this review is the use of targeted nanoparticles as an alternative to conventional pancreatic cancer treatment due to the various side effects of the latter. The principles of nanoparticle based cancer therapy is efficient targeting of tumour cells via enhanced permeability and retention (EPR) effects and decrease the chemotherapy side effects due to their non-specificity. To increase the efficiency of existing therapies and modify target nanoparticles, several molecular markers of pancreatic cancer cells have been identified. Thus pancreatic cancer cells can be detected using appropriately functionalized nanoparticles with specific signalling molecules. Once cancer has been identified, these nanoparticles can kill the tumour by inducing hyperthermia, medication delivery, immunotherapy or gene therapy. As potent co-delivery methods for adjuvants and tumor-associated antigens; nanoparticles (NPs) have demonstrated significant promise as delivery vehicles in cancer therapy. This ensures the precise internalization of the functionalized nanoparticle and thus also activates the immune system effectively against tumor cells. This review also discusses the immunological factors behind the uptake of functionalized nanoparticles in cancer therapies. Theranostics, which combine imaging and therapeutic chemicals in a single nanocarrier, are the next generation of medicines. Pancreatic cancer treatment may be revolutionised by the development of a tailored nanocarrier with diagnostic, therapeutic, and imaging capabilities. It is extremely difficult to incorporate various therapeutic modalities into a single nanocarrier without compromising the individual functionalities. Surface modification of nanocarriers with antibodies or proteins will enable to attain multifunctionality which increases the efficiency of pancreatic cancer therapy.

Metabolic reprogramming by mutant GNAS creates an actionable dependency in intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

Oncogenic 'hotspot' mutations of KRAS and GNAS are two major driver alterations in intraductal papillary mucinous neoplasms (IPMNs), which are bona fide precursors to pancreatic ductal adenocarcinoma. We previously reported that pancreas-specific Kras G12D and Gnas R201C co-expression in p48Cre; KrasLSL-G12D; Rosa26LSL-rtTA; Tg (TetO-GnasR201C) mice ('Kras;Gnas' mice) caused development of cystic lesions recapitulating IPMNs.

OBJECTIVE

We aim to unveil the consequences of mutant Gnas R201C expression on phenotype, transcriptomic profile and genomic dependencies.

DESIGN

We performed multimodal transcriptional profiling (bulk RNA sequencing, single-cell RNA sequencing and spatial transcriptomics) in the 'Kras;Gnas' autochthonous model and tumour-derived cell lines (Kras;Gnas cells), where Gnas R201C expression is inducible. A genome-wide CRISPR/Cas9 screen was conducted to identify potential vulnerabilities in KrasG12D;GnasR201C co-expressing cells.

RESULTS

Induction of Gnas R201C-and resulting G(s)alpha signalling-leads to the emergence of a gene signature of gastric (pyloric type) metaplasia in pancreatic neoplastic epithelial cells. CRISPR screening identified the synthetic essentiality of glycolysis-related genes Gpi1 and Slc2a1 in Kras G12D;Gnas R201C co-expressing cells. Real-time metabolic analyses in Kras;Gnas cells and autochthonous Kras;Gnas model confirmed enhanced glycolysis on Gnas R201C induction. Induction of Gnas R201C made Kras G12D expressing cells more dependent on glycolysis for their survival. Protein kinase A-dependent phosphorylation of the glycolytic intermediate enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) was a driver of increased glycolysis on Gnas R201C induction.

CONCLUSION

Multiple orthogonal approaches demonstrate that Kras G12D and Gnas R201C co-expression results in a gene signature of gastric pyloric metaplasia and glycolytic dependency during IPMN pathogenesis. The observed metabolic reprogramming may provide a potential target for therapeutics and interception of IPMNs.

Mural nodules and prevalence of high-grade dysplasia in branch duct intraductal papillary mucinous neoplasm of the pancreas undergoing resection

BACKGROUND

A mural module (MN) within a branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) could be a potential target for local treatment. The main aim was to describe the location of the highest grade of dysplasia relative to the mural module to assess the relevance of local treatment.

METHODS

Observational study of patients who underwent a pancreatic resection for suspected high-risk IPMN because of a mural module within a BD-IPMN (2012-2022). All patients had preoperative imaging confirming the enhancing mural module. The mural module was considered as a theoretical appropriate target for local destruction if no cancer or high-grade dysplasia (HGD) was described elsewhere than in the mural module.

RESULTS

Eighty-two patients (male: 44 (54%); mean age: 65 ± 9.2 years) were included. The mean size of BD-IPMN containing the mural module was 32 ± 14.8 mm. The mural module mean diameter was 10.5 ± 5.6 mm, and the main pancreatic duct (MPD) mean diameter was 5.2 ± 3.6 mm. Six patients presented invasive carcinoma (7%), 37 had HGD (45%), and 39 (48%) had exclusively low-grade dysplasia. The mural module was dysplastic in 70 cases (85%). The mural module was considered a relevant target for local ablation in 45 patients (55%), whereas 37 patients (45%) had HGD/invasive carcinoma distant from the mural module. HGD was exclusively present in the mural module in 6/82 patients (7%). Factors independently associated with 'relevant indication for local treatment' were female gender (P = 0.004; OR = 5.2, 95% c.i. 1.7 to 15.9) and MPD < 5 mm (P < 0.0001; OR = 8.6, 95% c.i. 2.7 to 26.8).

CONCLUSION

In resected pancreata, BD-IPMN mural modules are associated with HGD distant from the mural module almost half of cases. The findings question the safety of local treatment, supporting pancreatectomy as the best approach.

An Overview for Clinicians on Intraductal Papillary Mucinous Neoplasms (IPMNs) of the Pancreas

Currently, there is no reliable method of discerning between low-risk and high-risk intraductal papillary mucinous neoplasms (IPMNs). Operative resection is utilized in an effort to resect those lesions with high-grade dysplasia (HGD) prior to the development of invasive disease. The current guidelines recommend resection for IPMN that involve the main pancreatic duct. Resecting lesions with HGD before their progression to invasive disease and the avoidance of resection in those patients with low-grade dysplasia is the optimal clinical scenario. Therefore, the importance of developing preoperative models able to discern HGD in IPMN patients cannot be overstated. Low-risk patients should be managed with nonsurgical treatment options (typically MRI surveillance), while high-risk patients would undergo resection, hopefully prior to the formation of invasive disease. Current research is evolving in multiple directions. First, there is an ongoing effort to identify reliable markers for predicting malignant transformation of IPMN, mainly focusing on genomic and transcriptomic data from blood, tissue, and cystic fluid. Also, multimodal models of combining biomarkers with clinical and radiographic data seem promising for providing robust and accurate answers of risk levels for IPMN patients.

Molecular and Clinicopathologic Impact of GNAS Variants Across Solid Tumors

PURPOSE

The molecular drivers underlying mucinous tumor pathogenicity are poorly understood. GNAS mutations predict metastatic burden and treatment resistance in mucinous appendiceal adenocarcinoma. We investigated the pan-cancer clinicopathologic relevance of GNAS variants.

METHODS

We assessed 58,043 patients with Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (IMPACT)-sequenced solid tumors to identify oncogenic variants, including GNAS, associated with mucinous tumor phenotype. We then performed comprehensive molecular analyses to compare GNAS-mutant (mut) and wild-type tumors across cancers. Gene expression patterns associated with GNAS-mut tumors were assessed in a The Cancer Genome Atlas cohort. Associations between GNAS variant status and peritoneal metastasis, first-line systemic therapy response, progression-free survival (PFS), and overall survival (OS) were determined using a propensity-matched subcohort of patients with metastatic disease.

RESULTS

Mucinous tumors were enriched for oncogenic GNAS variants. GNAS was mutated in >1% of small bowel, cervical, colorectal, pancreatic, esophagogastric, hepatobiliary, and GI neuroendocrine cancers. Across these cancers, GNAS-mut tumors exhibited a generally conserved C-to-T mutation-high, aneuploidy-low molecular profile with co-occurring prevalent KRAS variants (65% of GNAS-mut tumors) and fewer TP53 alterations. GNAS-mut tumors exhibited recurrently comutated alternative tumor suppressors (RBM10, INPPL1) and upregulation of MAPK and cell surface modulators. GNAS-mut tumors demonstrate an increased prevalence of peritoneal metastases (odds ratio [OR], 1.7 [95% CI, 1.1 to 2.5]; P = .006), worse response to first-line systemic therapy (OR, 2.2 [95% CI, 1.3 to 3.8]; P = .003), and shorter PFS (median, 5.6 v 7.0 months; P = .047). In a multivariable analysis, GNAS mutated status was independently prognostic of worse OS (hazard ratio, 1.25 [95% CI, 1.01 to 1.56]; adjusted P = .04).

CONCLUSION

Across the assessed cancers, GNAS-mut tumors exhibit a conserved molecular and clinical phenotype defined by mucinous tumor status, increased peritoneal metastasis, poor response to first-line systemic therapy, and worse survival.

Light-gated integrator for highlighting kinase activity in living cells

Protein kinases are key signaling nodes that regulate fundamental biological and disease processes. Illuminating kinase signaling from multiple angles can provide deeper insights into disease mechanisms and improve therapeutic targeting. While fluorescent biosensors are powerful tools for visualizing live-cell kinase activity dynamics in real time, new molecular tools are needed that enable recording of transient signaling activities for post hoc analysis and targeted manipulation. Here, we develop a light-gated kinase activity coupled transcriptional integrator (KINACT) that converts dynamic kinase signals into "permanent" fluorescent marks. KINACT enables robust monitoring of kinase activity across scales, accurately recording subcellular PKA activity, highlighting PKA activity distribution in 3D cultures, and identifying PKA activators and inhibitors in high-throughput screens. We further leverage the ability of KINACT to drive signaling effector expression to allow feedback manipulation of the balance of GαsR201C-induced PKA and ERK activation and dissect the mechanisms of oncogenic G protein signaling.

Neoplastic Progression in Macroscopic Precursor Lesions of the Pancreas

CONTEXT.—

Macroscopic precursor lesions of the pancreas represent a complex clinical management problem. Molecular characterization of pancreatic cysts has helped to confirm and refine clinical and pathologic classifications of these lesions, inform our understanding of tumorigenesis in the pancreas, and provide opportunities for preoperative diagnosis.

OBJECTIVE.—

To review the pathologic classification of macroscopic cystic lesions of the pancreas: intraductal papillary mucinous neoplasms (IPMNs), mucinous cystic neoplasms (MCNs), intraductal oncocytic papillary neoplasms (IOPNs), and intraductal tubulopapillary neoplasms (ITPNs), and to describe our current state of understanding of their molecular underpinnings, relationship to invasive carcinomas, and implications for diagnosis and prognostication.

DATA SOURCES.—

We assessed the current primary literature and current World Health Organization Classification of Digestive System Tumours.

CONCLUSIONS.—

Macroscopic cystic lesions of the pancreas are morphologically and molecularly diverse. IPMNs and MCNs share mucinous cytoplasm with papillae. MCNs are defined by ovarian-type stroma. IOPNs have granular eosinophilic cytoplasm, prominent nucleoli, and complex, arborizing papillae. ITPNs demonstrate complex, back-to-back tubules and anastomosing papillae and lack prominent intracellular mucin. IPMNs and MCNs are characterized by driver mutations in KRAS/GNAS (IPMNs) and KRAS (MCNs), with later driver events in RNF43, CDKN2A, SMAD4, and TP53. In contrast, IOPNs and ITPNs have recurrent rearrangements in PRKACA/PRKACB and MAPK-associated genes, respectively. The recurrent alterations described in cysts provide an opportunity for diagnosis using aspirated cyst fluid. Molecular characterization of IPMNs shows a striking spatial and mutational heterogeneity, challenging traditional models of neoplastic development and creating challenges to interpretation of cyst fluid sequencing results.

KRAS and GNAS mutations in cell-free DNA and in circulating epithelial cells in patients with intraductal papillary mucinous neoplasms-an observational pilot study

Intraductal papillary mucinous neoplasms (IPMNs) are potential precursor lesions of pancreatic cancer. We assessed the efficacy of screening for KRAS proto-oncogene, GTPase (KRAS), and GNAS complex locus (GNAS) mutations in cell-free DNA (cfDNA)-using digital droplet polymerase chain reaction (ddPCR) and circulating epithelial cell (CEC) detection-as biomarkers for risk stratification in IPMN patients. We prospectively collected plasma samples from 25 resected patients at risk of malignant progression, and 23 under clinical surveillance. Our findings revealed KRAS mutations in 10.4% and GNAS mutations in 18.8% of the overall cohort. Among resected IPMN patients, KRAS and GNAS mutation detection rates were 16.0% and 32.0%, respectively, whereas both rates were 4.0% in conservatively managed IPMN. GNAS mutations in cfDNA were significantly more prevalent in resected IPMN (P = 0.024) compared with IPMN under surveillance. No CECs were detected. The absence of KRAS and GNAS mutations could be a reliable marker for branch duct IPMN without worrisome features. The emergence of GNAS mutations could prompt enhanced imaging surveillance. Neither the presence of established worrisome features nor GNAS or KRAS mutations appear effective in identifying high-grade dysplasia among IPMN patients.

Neoplastic Progression in Intraductal Papillary Neoplasm of the Bile Duct

CONTEXT.—

Intraductal papillary neoplasm of the bile duct (IPNB) is classified into types 1 and 2 based on criteria proposed in 2019. Recent studies investigated the clinicopathologic and molecular features of IPNB, which contributed to a more detailed understanding of this undercharacterized neoplasm.

OBJECTIVE.—

To summarize driver gene mutations, radiologic tumor evolution, and a potentially unique pattern of tumor progression in IPNB.

DATA SOURCES.—

Data were derived from a literature review and personal clinical and research experiences.

CONCLUSIONS.—

In contrast to de novo cholangiocarcinoma, type 1 IPNB often has mutations in APC, CTNNB1, STK11, and GNAS. These molecular features are shared with intraductal papillary mucinous neoplasm of the pancreas; however, the frequencies of individual gene abnormalities differ between these 2 neoplasms. A radiologic review of sequential images suggested that type 1 IPNB is a slow-growing neoplasm, with an ∼1-cm increase in size every 2 to 3 years, and remains in a noninvasive state for many years. A similar papillary neoplasm may develop in the biliary tree years after the complete surgical resection of IPNB. The second neoplasm has the same genetic abnormalities as the first neoplasm, indicating intrabiliary implantation rather than multifocal lesions. In contrast to type 1 IPNB, most cases of type 2 IPNB have invasive malignancy at the initial presentation. Type 2 IPNB shares many clinicopathologic and molecular features with de novo cholangiocarcinoma, questioning the distinctness of this tumor entity. The molecular mechanisms underlying malignant transformation in IPNB warrant further study.

Duodenal Fluid Analysis as a Rewarding Approach to Detect Low-Abundance Mutations in Biliopancreatic Cancers

Diagnosis of biliopancreatic cancers by the available serum tumor markers, imaging, and histopathological tissue specimen examination remains a challenge. Circulating cell-free DNA derived from matched pairs of secretin-stimulated duodenal fluid (DF) and plasma from 10 patients with biliopancreatic diseases and 8 control subjects was analyzed using AmpliSeq™ HD technology for Ion Torrent Next-Generation Sequencing to evaluate the potential of liquid biopsy with DF in biliopancreatic cancers. The median cfDNA concentration was greater in DF-derived than in plasma-derived samples. A total of 13 variants were detected: 11 vs. 1 were exclusive for DF relative to the plasma source, and 1 was shared between the two body fluids. According to the four-tier systems, 10 clinical tier-I-II (76.9%), 1 tier-III (7.7%), and 2 tier-IV (15.4%) variants were identified. Notably, the 11 tier-I-III variants were exclusively found in DF-derived cfDNA from five patients with biliopancreatic cancers, and were detected in seven genes (KRAS, TP53, BRAF, CDKN2A, RNF43, GNAS, and PIK3CA); 82% of the tier-I-III variants had a low abundance, with a VAF < 6%. The mutational profiling of DF seems to be a reliable and promising tool for identifying cancer-associated alterations in malignant cancers of the biliopancreatic tract.

Oncogenic GNAS Uses PKA-Dependent and Independent Mechanisms to Induce Cell Proliferation in Human Pancreatic Ductal and Acinar Organoids

IMPLICATIONS

The study identifies an opportunity to discover a PKA-independent pathway downstream of oncogene GNAS for managing IPMN lesions and their progression to PDAC.

3D genomic mapping reveals multifocality of human pancreatic precancers

Pancreatic intraepithelial neoplasias (PanINs) are the most common precursors of pancreatic cancer, but their small size and inaccessibility in humans make them challenging to study1. Critically, the number, dimensions and connectivity of human PanINs remain largely unknown, precluding important insights into early cancer development. Here, we provide a microanatomical survey of human PanINs by analysing 46 large samples of grossly normal human pancreas with a machine-learning pipeline for quantitative 3D histological reconstruction at single-cell resolution. To elucidate genetic relationships between and within PanINs, we developed a workflow in which 3D modelling guides multi-region microdissection and targeted and whole-exome sequencing. From these samples, we calculated a mean burden of 13 PanINs per cm3 and extrapolated that the normal intact adult pancreas harbours hundreds of PanINs, almost all with oncogenic KRAS hotspot mutations. We found that most PanINs originate as independent clones with distinct somatic mutation profiles. Some spatially continuous PanINs were found to contain multiple KRAS mutations; computational and in situ analyses demonstrated that different KRAS mutations localize to distinct cell subpopulations within these neoplasms, indicating their polyclonal origins. The extensive multifocality and genetic heterogeneity of PanINs raises important questions about mechanisms that drive precancer initiation and confer differential progression risk in the human pancreas. This detailed 3D genomic mapping of molecular alterations in human PanINs provides an empirical foundation for early detection and rational interception of pancreatic cancer.

Comparative molecular profiling of pancreatic ductal adenocarcinoma of the head versus body and tail

Pancreatic ductal adenocarcinoma (PDAC) of the head (H) and body/tail (B/T) differ in embryonic origin, cell composition, blood supply, lymphatic and venous drainage, and innervation. We aimed to compare the molecular and tumor immune microenvironment (TIME) profiles of PDAC of the H vs. B/T. A total of 3499 PDAC samples were analyzed via next-generation sequencing (NGS) of RNA (whole transcriptome, NovaSeq), DNA (NextSeq, 592 genes or NovaSeq, whole exome sequencing), and immunohistochemistry (Caris Life Sciences, Phoenix, AZ). Significance was determined as p values adjusted for multiple corrections (q) of <0.05. Anatomic subsites of PDAC tumors were grouped by primary tumor sites into H (N = 2058) or B/T (N = 1384). There were significantly more metastatic tumors profiled from B/T vs. H (57% vs. 44%, p < 0.001). KRAS mutations (93.8% vs. 90.2%), genomic loss of heterozygosity (12.7% vs. 9.1%), and several copy number alterations (FGF3, FGF4, FGF19, CCND1, ZNF703, FLT4, MUTYH, TNFRS14) trended higher in B/T when compared to H (p < 0.05 but q > 0.05). Expression analysis of immuno-oncology (IO)-related genes showed significantly higher expression of CTLA4 and PDCD1 in H (q < 0.05, fold change 1.2 and 1.3) and IDO1 and PDCD1LG2 expression trended higher in B/T (p < 0.05, fold change 0.95). To our knowledge, this is one of the largest cohorts of PDAC tumors subjected to broad molecular profiling. Differences in IO-related gene expression and TIME cell distribution suggest that response to IO therapies may differ in PDAC arising from H vs. B/T. Subtle differences in the genomic profiles of H vs. B/T tumors were observed.

Light-gated Integrator for Highlighting Kinase Activity in Living Cells

Protein kinases are key signaling nodes that regulate fundamental biological and disease processes. Illuminating kinase signaling from multiple angles can provide deeper insights into disease mechanisms and improve therapeutic targeting. While fluorescent biosensors are powerful tools for visualizing live-cell kinase activity dynamics in real time, new molecular tools are needed that enable recording of transient signaling activities for post hoc analysis and targeted manipulation. Here, we develop a light-gated kinase activity coupled transcriptional integrator (KINACT) that converts dynamic kinase signals into "permanent" fluorescent marks. KINACT enables robust monitoring of kinase activity across scales, accurately recording subcellular PKA activity, highlighting PKA signaling heterogeneity in 3D cultures, and identifying PKA activators and inhibitors in high-throughput screens. We further leverage the ability of KINACT to drive signaling effector expression to allow feedback manipulation of the balance of GαsR201C-induced PKA and ERK activation and dissect the mechanisms of oncogenic G protein signaling.

Molecular Pathology of Pancreatic Cystic Lesions with a Focus on Malignant Progression

The malignant progression of pancreatic cystic lesions (PCLs) remains understudied with a knowledge gap, yet its exploration is pivotal for effectively stratifying patient risk and detecting cancer at its earliest stages. Within this review, we delve into the latest discoveries on the molecular level, revealing insights into the IPMN molecular landscape and revised progression model, associated histologic subtypes, and the role of inflammation in the pathogenesis and malignant progression of IPMN. Low-grade PCLs, particularly IPMNs, can develop into high-grade lesions or invasive carcinoma, underscoring the need for long-term surveillance of these lesions if they are not resected. Although KRAS and GNAS remain the primary oncogenic drivers of neoplastic development in IPMNs, additional genes that are important in tumorigenesis have been recently identified by whole exome sequencing. A more complete understanding of the genes involved in the molecular progression of IPMN is critical for effective monitoring to minimize the risk of malignant progression. Complicating these strategies, IPMNs are also frequently multifocal and multiclonal, as demonstrated by comparative molecular analysis. Algorithms for preoperative cyst sampling and improved radiomic techniques are emerging to model this spatial and temporal genetic heterogeneity better. Here, we review the molecular pathology of PCLs, focusing on changes associated with malignant progression. Developing models of molecular risk stratification in PCLs which can complement radiologic and clinical features, facilitate the early detection of pancreatic cancer, and enable the development of more personalized surveillance and management strategies are summarized.

Dysplasia and Early Carcinoma of the Gallbladder and Bile Ducts: Terminology, Classification, and Significance

Most precursor lesions and early cancerous changes in the gallbladder and bile ducts present as clinically/grossly inapparent lesions. Low-grade dysplasia is difficult to define and clinically inconsequential by itself; however, extra sampling is required to exclude accompanying significant lesions. For high-grade dysplasia ('carcinoma in situ'), a complete sampling is necessary to rule out invasion. Tumoral intramucosal neoplasms (ie, intracholecystic and intraductal neoplasia) form radiologically/grossly visible masses, and they account for (present in the background of) about 5% to 10% of invasive cancers of the region. These reveal a spectrum of papilla/tubule formation, cell lineages, and dysplastic transformation. Some subtypes such as intracholecystic tubular non-mucinous neoplasm of the gallbladder (almost never invasive) and intraductal oncocytic or intraductal tubulopapillary neoplasms of the bile ducts (may have a protracted clinical course even when invasive) are to be noted separately. Other types of intracholecystic/intraductal neoplasia have a high frequency of invasive carcinoma and progressive behavior, which often culminates in mortality.

ASO Practice Guidelines Series: Management of Resectable, Borderline Resectable, and Locally Advanced Pancreas Cancer

Pancreatic adenocarcinoma is an aggressive disease marked by high rates of both local and distant failure. In the minority of patients with potentially resectable disease, multimodal treatment paradigms have allowed for prolonged survival in an increasingly larger pool of well-selected patients. Therefore, it is critical for surgical oncologists to be abreast of current guideline recommendations for both surgical management and multimodal therapy for pancreas cancer. We discuss these guidelines, as well as the underlying data supporting these positions, to offer surgical oncologists a framework for managing patients with pancreatic adenocarcinoma.

Early Cancerous Lesions of the Pancreas and Ampulla: Current Concepts and Challenges

Owing to the increased use of advanced imaging techniques, mass-forming (cystic/intraductal) preinvasive neoplasms are being detected much more frequently and they have rapidly become one of the main focuses of interests in medical field. These neoplasms have very distinctive clinical and radiographic findings, exhibit a spectrum of dysplastic transformation, from low-grade dysplasia to high-grade dysplasia, and may be associated with an invasive carcinoma. Accounting for about 5% to 10% of pancreatic ductal adenocarcinomas, they provide a curable target subset in an otherwise biologically dismal pancreas cancer category.

[Challenges of cytopathological pancreas diagnostics]

The cytologic diagnostics of solid and cystic pancreatic lesions with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an integral part of the clinical workup and the decision of a surgical versus a conservative approach. Cystic lesions are increasingly being diagnosed due to improved imaging and represent numerous neoplastic as well as non-neoplastic epithelial and non-epithelial entities, which differ in biological behavior and prognosis. In particular, the differentiation of mucinous and non-mucinous cysts is significant for further clinical management. Regressive cellular changes, gastrointestinal contaminants, and overlapping morphologic changes of reactively altered ductal epithelial cells and cells of well-differentiated neoplasms and preneoplasms are special challenges of cytological diagnostics. For a uniform cytological classification of findings, an internationally developed seven-level classification system has been published and co-published by the World Health Organization (WHO). This classification system takes into account both morphological findings and further procedures on cytological material such as next-generation sequencing and immunocytochemistry and is based on the WHO classification for pancreatic tumors. Against this background, important cytologic diagnostic criteria of various solid and cystic lesions relevant in clinical practice are presented in this article, considering diagnostic possibilities and pitfalls as well as differential diagnoses.

Premalignant Lesions in the Kidney Transplant Candidate

End-stage kidney disease patients who are referred for transplant undergo an extensive evaluation process to ensure their health prior to transplant due in part to the shortage of available organs. Although management and surveillance guidelines exist for malignancies identified in the transplant and waitlist populations, less is written about the management of premalignant lesions in this population. This review covers the less common premalignant lesions (intraductal papillary mucinous neoplasm, gastrointestinal stromal tumor, thymoma, and pancreatic neuroendocrine tumor) that can be found in the transplant candidate population. High-level evidence for the management of these rarer premalignant lesions in the transplant population is lacking, and this review extrapolates evidence from the general population and should not be a substitute for a multidisciplinary discussion with medical and surgical oncologists.

Case report: Genetic analysis of a novel intronic inversion variant in the SPTB gene associated with hereditary spherocytosis

Background: Hereditary spherocytosis (HS) is a congenital haemolytic anaemia attributed to dysregulation or abnormal quantities of erythrocyte membrane proteins. Currently, the most common erythrocytic gene, spectrin β (SPTB), variants are located in exons and give rise to mRNA defects. However, the genetic characteristics and pathogenic mechanisms of SPTB intronic variants are not completely understood. This study aimed to analyse a rare intronic inversion variant in the SPTB gene associated with HS, and explore the impact of the variant on SPTB mRNA splicing. Method: The clinical manifestations of the patient were summarised and analysed for spherocytosis phenotype diagnosis. The pathogenic variant was identified in the proband using targeted next-generation and Sanger sequencing. RNA sequencing was performed to analyse whether SPTB gene splicing and expression were affected. Results: Targeted next-generation sequencing identified a novel disease-associated intronic inversion variant of the SPTB gene in the proband. The inversion variant was located between intron 19 and 20, and contained the entire exon 20 and partial sequences of adjacent introns. Sanger sequencing confirmed that the intronic inversion variant only appeared in the genome of the proband, not in his parents. RNA sequencing revealed that the variant could result in the skipping of exon 20 and reduced expression of SPTB mRNA. Conclusion: This study identifies a rare intronic inversion variant in the SPTB gene associated with hereditary spherocytosis. The pathogenic variant can lead to exon 20 skipping and decreased SPTB gene expression. This finding has not been previously reported in any literature. This study can expand the intronic variant spectrum of the SPTB gene, deepen our understanding of HS pathogenesis, and contribute to the genetic diagnosis and clinical management of patients.

Spectrum of variants in a large Chinese Gitelman syndrome cohort

Gitelman syndrome (GS) is caused by SLC12A3 biallelic variants. A previous study showed that large rearrangements (LRGs) of SLC12A3 accounted for the low sensitivity of genetic testing. However, a systematic screening for LRGs in Chinese GS patients is lacking. Massively parallel sequencing (MPS) and multiplex ligation-dependent probe amplification (MLPA) were performed to sequence the genomic DNA of patients with clinically diagnosed GS. Of 165 index cases, MPS identified 151 cases with two or more affected alleles and 14 cases with one variant allele. LRGs were detected by MLPA in 20 out of 27 cases, including 15 cases with suspected LRGs by MPS. Among these 20 cases with LRGs, the results of MPS and MLPA were identical in only 8 cases. Additional LRGs in 6 cases were detected by MLPA alone. In 6 cases, E4_E6del was identified by MPS, while E4_E5del and Intron6del were identified by MLPA. Among the 102 distinct variants, 30 are novel. LRGs were found in 20 cases (12.1%). LRGs were found in 12.1% of our Chinese GS patients cohort. We show that MPS and MLPA are two complementary techniques with the ability to improve the diagnostic yield of GS.

KRAS Wild-Type Pancreatic Cancer: Decoding Genomics, Unlocking Therapeutic Potential

In a landscape dominated by pivotal KRAS mutations, there has been limited exploration of KRAS wild-type pancreatic cancer. A recent study highlights other mitogen-activated kinase pathway alterations as alternative drivers in these tumors, which holds the key to unlocking a realm of targeted therapies for patients with this understudied cancer subtype. See related article by Singh et al., p. 4627.

Circulating tumor DNA in unresectable pancreatic cancer is a strong predictor of first-line treatment efficacy: The KRASCIPANC prospective study

BACKGROUND

There is no robust predictor of response to chemotherapy (CT) in unresectable pancreatic adenocarcinomas (UPA). The objective of the KRASCIPANC study was to analyze the kinetics of cell-free DNA (cfDNA)/circulating tumor DNA (ctDNA) as a predictor of response to CT in UPA.

METHODS

Blood samples were collected just before first CT and at day 28. The primary endpoint was the kinetics of KRAS-mutated ctDNA by digital droplet PCR between D0 and D28 as a predictor of progression-free survival (PFS).

RESULTS

We analyzed 65 patients with a KRAS-mutated tumor. A high level of cfDNA and KRAS-mutated ctDNA at D0, as well as the presence of KRAS-mutated ctDNA at D28, were strongly associated with lower centralized disease control rate (cDCR), shorter cPFS and OS in multivariate analysis. A score combining cfDNA level at diagnosis ≥ or <30 ng/mL and presence or not of KRAS-mutated ctDNA at D28 was an optimal predictor of cDCR (OR=30.7, IC95% 4.31-218 P=.001), PFS (HR=6.79, IC95% 2.76-16.7, P<.001) and OS (HR=9.98, IC95% 4.14-24.1, P<.001).

CONCLUSION

A combined score using cfDNA level at diagnosis and KRAS-mutated ctDNA at D28 is strongly associated with patient survival/response to chemotherapy in UPA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04560270.

Activation of melanocortin-1 receptor signaling in melanoma cells impairs T cell infiltration to dampen antitumor immunity

Inhibition of T cell infiltration dampens antitumor immunity and causes resistance to immune checkpoint blockade (ICB) therapy. By in vivo CRISPR screening in B16F10 melanoma in female mice, here we report that loss of melanocortin-1 receptor (MC1R) in melanoma cells activates antitumor T cell response and overcomes resistance to ICB. Depletion of MC1R from another melanocytic melanoma model HCmel1274 also enhances ICB efficacy. By activating the GNAS-PKA axis, MC1R inhibits interferon-gamma induced CXCL9/10/11 transcription, thus impairing T cell infiltration into the tumor microenvironment. In human melanomas, high MC1R expression correlates with reduced CXCL9/10/11 expression, impaired T cell infiltration, and poor patient prognosis. Whereas MC1R activation is restricted to melanoma, GNAS activation by hotspot mutations is observed across diverse cancer types and is associated with reduced CXCL9/10/11 expression. Our study implicates MC1R as a melanoma immunotherapy target and suggests GNAS-PKA signaling as a pan-cancer oncogenic pathway inhibiting antitumor T cell response.

Low-Pass Genomic Sequencing Reveals Novel Subtypes of Pancreatic Cystic Neoplasms

BACKGROUND

Over the years, the detection rate of pancreatic cystic neoplasms (PCNs) has significantly increased; however, the differential diagnosis and identification of high-risk PCNs remain challenging. We sought to investigate whether chromosomal instability (CIN) features in cell-free DNA in the cystic fluid of PCNs could help to identify high-risk PCNs.

METHODS

Pancreatic cystic fluid samples from 102 patients with PCNs were intraoperatively collected for detection of CIN using an ultrasensitive chromosomal aneuploidy detector. Clinical and imaging data were retrospectively collected, and statistical analysis was performed to assess the potential role of CIN in clinical practice.

RESULTS

CIN was investigated in a total of 100 patients. Sixteen of 26 serous cystic cystadenomas (SCAs) harbored deletions of chr3p and/or chr6p, whereas low rates of CIN were detected in mucinous cystic neoplasms. Most malignant PCNs presented with more than one type of CIN; amplification of chr1q and chr8q found in nine and seven of 11 malignant PCNs (81.8% and 63.6%), respectively, could aid in distinguishing high-risk IPMNs from low-risk ones, with a higher sensitivity than imaging. A combination of the mural nodule imaging feature and amplification of chr1q and chr8q achieved a sensitivity of 70.0% and a specificity of 82.4% in identifying high-risk IPMNs.

CONCLUSIONS

Our work revealed the distinct CIN signature of different types of PCNs. Deletions of chr3p and chr6p defined a subtype of SCAs. Gains of chr1q and chr8q were associated with insidious malignant PCNs and helped identify high-risk IPMNs.

The Dual Role of Necroptosis in Pancreatic Ductal Adenocarcinoma

Pancreatic cancer (PC) is the seventh leading cause of cancer-related death. PC incidence has continued to increase by about 1% each year in both men and women. Although the 5-year relative survival rate of PC has increased from 3% to 12%, it is still the lowest among cancers. Hence, novel therapeutic strategies are urgently needed. Challenges in PC-targeted therapeutic strategies stem from the high PC heterogeneity and from the poorly understood interplay between cancer cells and the surrounding microenvironment. Signaling pathways that drive PC cell growth have been the subject of intense scrutiny and interest has been attracted by necroptosis, a distinct type of programmed cell death. In this review, we provide a historical background on necroptosis and a detailed analysis of the ongoing debate on the role of necroptosis in PC malignant progression.

Pancreatic Cyst Fluid Analysis

Pancreatic cyst fluid analysis can help diagnose pancreatic cyst type and the risk of high-grade dysplasia and cancer. Recent evidence from molecular analysis of cyst fluid has revolutionized the field with multiple markers showing promise in accurate diagnosis and prognostication of pancreatic cysts. The availability of multi-analyte panels has great potential for more accurate prediction of cancer.

Circulating tumour DNA kinetics in recurrent/metastatic head and neck squamous cell cancer patients

PURPOSE

Immune checkpoint blockade (ICB) has become a standard of care in the treatment of recurrent/metastatic head and neck squamous cell cancer (R/M HNSCC). However, only a subset of patients benefit from treatment. Quantification of plasma circulating tumour DNA (ctDNA) levels and on-treatment kinetics may permit real-time assessment of disease burden under selective pressures of treatment.

PATIENTS AND METHODS

R/M HNSCC patients treated with systemic therapy, platinum-based chemotherapy (CT) or ICB, underwent serial liquid biopsy sampling. Biomarkers tested included ctDNA measured by CAncer Personalized Profiling by deep Sequencing (CAPP-Seq) and markers of host inflammation measured by neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR).

RESULTS

Among 53 eligible patients, 16 (30%) received CT, 30 (57%) ICB [anti-PD1/L1] monotherapy and 7 (13%) combination immunotherapy (IO). Median progression-free survival (PFS) and overall survival (OS) were 2.8 months (95% CI, 1.3-4.3) and 8.2 months (95% CI, 5.6-10.8), respectively. Seven (13%) patients experienced a partial response and 21 (40%) derived clinical benefit. At baseline, median ctDNA variant allele frequency (VAF) was 4.3%. Baseline ctDNA abundance was not associated with OS (p = 0.56) nor PFS (p = 0.54). However, a change in ctDNA VAF after one cycle of treatment (ΔVAF (T1-2)) was predictive of both PFS (p< 0.01) and OS (p< 0.01). Additionally, decrease in ΔVAF identified patients with longer OS despite early radiological progression, 8.2 vs 4.6 months, hazard ratio 0.44 (95% CI, 0.19-0.87) p = 0.03. After incorporating NLR and PLR into multivariable Cox models, ctDNA ∆VAF retained an association with OS.

CONCLUSIONS

Early dynamic changes in ctDNA abundance, after one cycle of treatment, compared to baseline predicted both OS and PFS in R/M HNSCC patients on systemic therapy.

Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Challenging Diagnosis

Intraductal papillary mucinous neoplasm of the pancreas (IPMN) was classified as a distinct entity from mucinous cystic neoplasm by the WHO in 1995. It represents a mucin-producing tumor that originates from the ductal epithelium and can evolve from slight dysplasia to invasive carcinoma. In addition, different aspects of tumor progression may be seen in the same lesion. Three types are recognized, the branch duct variant, the main duct variant, which shows a much higher prevalence for malignancy, and the mixed-type variant, which combines branch and main duct characteristics. Advances in cross-sectional imaging have led to an increased rate of IPMN detection. The main imaging characteristic of IPMN is the dilatation of the pancreatic duct without the presence of an obstructing lesion. The diagnosis of a branch duct IPMN is based on the proof of its communication with the main pancreatic duct on MRI-MRCP examination. Early identification by imaging of the so-called worrisome features or predictors for malignancy is an important and challenging task. In this review, we will present recent imaging advances in the diagnosis and characterization of different types of IPMNs, as well as imaging tools available for early recognition of worrisome features for malignancy. A critical appraisal of current IPMN management guidelines from both a radiologist's and surgeon's perspective will be made. Special mention is made of complications that might arise during the course of IPMNs as well as concomitant pancreatic neoplasms including pancreatic adenocarcinoma and pancreatic endocrine neoplasms. Finally, recent research on prognostic and predictive biomarkers including radiomics will be discussed.

Comprehensive DNA Methylation Analysis Indicates That Pancreatic Intraepithelial Neoplasia Lesions Are Acinar-Derived and Epigenetically Primed for Carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) is believed to arise from the accumulation of a series of somatic mutations and is also frequently associated with pancreatic intraepithelial neoplasia (PanIN) lesions. However, there is still debate as to whether the cell type-of-origin of PanINs and PDACs in humans is acinar or ductal. As cell type identity is maintained epigenetically, DNA methylation changes during pancreatic neoplasia can provide a compelling perspective to examine this question. Here, we performed laser-capture microdissection on surgically resected specimens from 18 patients to isolate, with high purity, DNA for whole-genome bisulfite sequencing from four relevant cell types: acini, nonneoplastic ducts, PanIN lesions, and PDAC lesions. Differentially methylated regions (DMR) were identified using two complementary analytical approaches: bsseq, which identifies any DMRs but is particularly useful for large block-like DMRs, and informME, which profiles the potential energy landscape across the genome and is particularly useful for identifying differential methylation entropy. Both global methylation profiles and block DMRs clearly implicated an acinar origin for PanINs. At the gene level, PanIN lesions exhibited an intermediate acinar-ductal phenotype resembling acinar-to-ductal metaplasia. In 97.6% of PanIN-specific DMRs, PanIN lesions had an intermediate methylation level between normal and PDAC, which suggests from an information theory perspective that PanIN lesions are epigenetically primed to progress to PDAC. Thus, epigenomic analysis complements histopathology to define molecular progression toward PDAC. The shared epigenetic lineage between PanIN and PDAC lesions could provide an opportunity for prevention by targeting aberrantly methylated progression-related genes.

SIGNIFICANCE

Analysis of DNA methylation landscapes provides insights into the cell-of-origin of PanIN lesions, clarifies the role of PanIN lesions as metaplastic precursors to human PDAC, and suggests potential targets for chemoprevention.

Research progress and future directions on intraductal papillary mucinous neoplasm: A bibliometric and visualized analysis of over 30 years of research

BACKGROUND

Malignant change from low-grade dysplasia to high-grade dysplasia and invasive carcinoma following an adenoma-carcinoma sequence is becoming more common in intraductal papillary mucinous neoplasm (IPMN) of the pancreas. The aim of this study is to analyze their main characteristics and recent research trends in IPMNs and consequently create better understandings of the current situation and trends.

METHODS

A comprehensive search was performed in The Science Citation Index Expanded of the Web of Science. All articles between 1990 and 2021 were searched. VOS viewer (Leiden University, Leiden, Netherlands) was used for a qualitative and quantitative analysis of keywords, constituting maps based on co-occurrence matrix.

RESULTS

A total of 1658 eligible articles were screened among the 3950 identified articles for this subject. Finally, 879 articles were included in this study. Many articles on IPMN have been published in Japan and South Korea. Tanaka published the highest number of articles (n = 26, citations = 11,143). The Pancreas published the highest number of articles. (n = 100, citations = 2533). These articles were grouped into 4 clusters including basic research, disease overview, management/prognosis and malignant IPMN by using bibliometric keywords network analysis. Overlay visualization demonstrates, a trend of the studies has been changed from basic research or disease to management or prognosis.

CONCLUSIONS

In this study, we found and highlight the most cited and influential articles related to IPMN. Plus, this study analyzed global research trends in IPMN over the past 30 years and provides insight into the features and research hotspots of the articles in IPMN research.

Molecular Classification of Appendiceal Adenocarcinoma

PURPOSE

Appendiceal adenocarcinomas (ACs) are rare, histologically diverse malignancies treated as colorectal cancers despite having distinct biology and clinical behavior. To guide clinical decision making, we defined molecular subtypes of AC associated with patient survival, metastatic burden, and chemotherapy response.

PATIENTS AND METHODS

A comprehensive molecular analysis was performed in patients with AC to define molecular subtypes. Associations between molecular subtype and overall survival, intraoperative peritoneal cancer index, and first-line chemotherapy response were assessed adjusting for histopathologic and clinical variables using multivariable Cox proportional hazards, linear regression, and logistic regression models.

RESULTS

We defined distinct molecular lineages of mucinous appendiceal adenocarcinoma (MAAP) from co-occurring mutations in GNAS, RAS, and TP53. Of 164 MAAP tumors, 24 were RAS-mutant (mut) predominant (RAS-mut/GNAS-wild-type [wt]/TP53-wt) with significantly decreased mutations and chromosomal alterations compared with tumors with GNAS mutations (GNAS-mut predominant) or TP53 mutations (TP53-mut predominant). No patient with RAS-mut predominant subtype metastatic MAAP died of cancer, and overall survival in this subgroup was significantly improved compared with patients with GNAS-mut (P = .05) and TP53-mut (P = .004) predominant subtypes. TP53-mut predominant subtypes were highly aneuploid; increased tumor aneuploidy was independently (P = .001) associated with poor prognosis. The findings retained significance in patients with any metastatic AC. RAS-mut predominant metastases exhibited reduced peritoneal tumor bulk (P = .04) and stromal invasion (P < .001) compared with GNAS-mut or TP53-mut predominant tumors, respectively. Patients with RAS-mut predominant MAAP responded more to first-line chemotherapy (50%) compared with patients with GNAS-mut predominant tumors (6%, P = .03).

CONCLUSION

AC molecular patterns identify distinct molecular subtypes: a clinically indolent RAS-mut/GNAS-wt/TP53-wt subtype; a chemotherapy-resistant GNAS-mut predominant subtype; and an aggressive, highly aneuploid TP53-mut predominant subtype. Each subtype exhibits conserved clinical behavior irrespective of histopathology.

Adenosquamous carcinoma coexisting with intraductal papillary mucinous neoplasm of the pancreas: a case report

BACKGROUND

Adenosquamous carcinoma of the pancreas is a rare variant, with a worse prognosis than pancreatic ductal adenocarcinoma; moreover, it has characteristic clinical and histopathological features. Studies have mentioned the differentiation of intraductal papillary mucinous neoplasms into mucinous/tubular adenocarcinomas; however, their transdifferentiation into adenosquamous carcinoma remains unclear.

CASE PRESENTATION

An 80-year-old Japanese woman was referred to our hospital for further examination of multiple pancreatic cysts. Enhanced computed tomography after close follow-up for 6 years revealed a new nodule with poor enhancement on the pancreatic body. Distal pancreatectomy and splenectomy were performed. Histopathological examination revealed an adenosquamous carcinoma with coexisting intraductal papillary mucinous neoplasms; moreover, the intraductal papillary mucinous neoplasms lacked continuity with the adenosquamous carcinoma. Immunohistochemical analysis revealed squamous cell carcinoma and differentiation from adenocarcinoma to squamous cell carcinoma. Gene mutation analysis revealed KRASG12D and KRASG12R mutations in adenosquamous carcinoma components and intraductal papillary mucinous neoplasm lesions, respectively, with none showing the mutation of GNAS codon 201. The final histopathological diagnosis was adenosquamous carcinoma with coexisting intraductal papillary mucinous neoplasms of the pancreas.

CONCLUSIONS

This is the rare case of adenosquamous carcinoma with coexisting intraductal papillary mucinous neoplasms of the pancreas. To investigate the underlying transdifferentiation pathway of intraductal papillary mucinous neoplasms into this rare subtype of pancreatic cancer, we explored gene mutation differences as a clinicopathological parameter.

Three-dimensional genomic mapping of human pancreatic tissue reveals striking multifocality and genetic heterogeneity in precancerous lesions

Pancreatic intraepithelial neoplasia (PanIN) is a precursor to pancreatic cancer and represents a critical opportunity for cancer interception. However, the number, size, shape, and connectivity of PanINs in human pancreatic tissue samples are largely unknown. In this study, we quantitatively assessed human PanINs using CODA, a novel machine-learning pipeline for 3D image analysis that generates quantifiable models of large pieces of human pancreas with single-cell resolution. Using a cohort of 38 large slabs of grossly normal human pancreas from surgical resection specimens, we identified striking multifocality of PanINs, with a mean burden of 13 spatially separate PanINs per cm3 of sampled tissue. Extrapolating this burden to the entire pancreas suggested a median of approximately 1000 PanINs in an entire pancreas. In order to better understand the clonal relationships within and between PanINs, we developed a pipeline for CODA-guided multi-region genomic analysis of PanINs, including targeted and whole exome sequencing. Multi-region assessment of 37 PanINs from eight additional human pancreatic tissue slabs revealed that almost all PanINs contained hotspot mutations in the oncogene KRAS, but no gene other than KRAS was altered in more than 20% of the analyzed PanINs. PanINs contained a mean of 13 somatic mutations per region when analyzed by whole exome sequencing. The majority of analyzed PanINs originated from independent clonal events, with distinct somatic mutation profiles between PanINs in the same tissue slab. A subset of the analyzed PanINs contained multiple KRAS mutations, suggesting a polyclonal origin even in PanINs that are contiguous by rigorous 3D assessment. This study leverages a novel 3D genomic mapping approach to describe, for the first time, the spatial and genetic multifocality of human PanINs, providing important insights into the initiation and progression of pancreatic neoplasia.

Genetics, Genomics and Emerging Molecular Therapies of Pancreatic Cancer

The number of cases of pancreatic cancers in 2019 in Poland was 3852 (approx. 2% of all cancers). The course of the disease is very fast, and the average survival time from the diagnosis is 6 months. Only <2% of patients live for 5 years from the diagnosis, 8% live for 2 years, and almost half live for only about 3 months. A family predisposition to pancreatic cancer occurs in about 10% of cases. Several oncogenes in which somatic changes lead to the development of tumours, including genes BRCA1/2 and PALB2, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1, are involved in pancreatic cancer. Between 4% and 10% of individuals with pancreatic cancer will have a mutation in one of these genes. Six percent of patients with pancreatic cancer have NTRK pathogenic fusion. The pathogenesis of pancreatic cancer can in many cases be characterised by homologous recombination deficiency (HRD)-cell inability to effectively repair DNA. It is estimated that from 24% to as many as 44% of pancreatic cancers show HRD. The most common cause of HRD are inactivating mutations in the genes regulating this DNA repair system, mainly BRCA1 and BRCA2, but also PALB2, RAD51C and several dozen others.

Oncogenic GNAS uses PKA-dependent and independent mechanisms to induce cell proliferation in human pancreatic ductal and acinar organoids

Ductal and acinar pancreatic organoids generated from human pluripotent stem cells (hPSCs) are promising models to study pancreatic diseases, including precursor lesions of pancreatic cancer. Genome sequencing studies have revealed that mutations in a G-protein (GNASR201C) are exclusively observed in intraductal papillary mucinous neoplasms (IPMNs), one of the most common cystic pancreatic precancerous lesions. GNASR201C cooperates with oncogenic KRASG12V/D to produce IPMN lesions in mice; however, the biological mechanisms by which oncogenic GNAS affects the ductal and acinar exocrine pancreas are not understood. In this study, we use pancreatic ductal and acinar organoids generated from human embryonic stem cells to investigate mechanisms by which GNASR201C functions. As expected, GNASR201C-induced cell proliferation in acinar organoids was PKA-dependent. Surprisingly, GNASR201C-induced cell proliferation independent of the canonical PKA signaling in short-term and stable, long-term cultures of GNAS-expressing ductal organoids and in an immortalized ductal epithelial cell line, demonstrating that GNASR201C uses PKA-dependent and independent mechanisms to induce cell proliferation in the exocrine pancreas. Co-expression of oncogenic KRASG12V and GNASR201C induced cell proliferation in ductal and acini organoids in a PKA-independent and dependent manner, respectively. Thus, we identify cell lineage-specific roles for PKA signaling driving pre-cancerous lesions and report the development of a human pancreatic ductal organoid model system to investigate mechanisms regulating GNASR201C-induced IPMNs.

Surgical treatment for pancreatic cystic lesions-implications from the multi-center and prospective German StuDoQ|Pancreas registry

PURPOSE

The detection of pancreatic cystic lesions (PCL) causes uncertainty for physicians and patients, and international guidelines are based on low evidence. The extent and perioperative risk of resections of PCL in Germany needs comparison with these guidelines to highlight controversies and derive recommendations.

METHODS

Clinical data of 1137 patients who underwent surgery for PCL between 2014 and 2019 were retrieved from the German StuDoQ|Pancreas registry. Relevant features for preoperative evaluation and predictive factors for adverse outcomes were statistically identified.

RESULTS

Patients with intraductal papillary mucinous neoplasms (IPMN) represented the largest PCL subgroup (N = 689; 60.6%) while other entities (mucinous cystic neoplasms (MCN), serous cystic neoplasms (SCN), neuroendocrine tumors, pseudocysts) were less frequently resected. Symptoms of pancreatitis were associated with IPMN (OR, 1.8; P = 0.012) and pseudocysts (OR, 4.78; P < 0.001), but likewise lowered the likelihood of MCN (OR, 0.49; P = 0.046) and SCN (OR, 0.15, P = 0.002). A total of 639 (57.2%) patients received endoscopic ultrasound before resection, as recommended by guidelines. Malignancy was histologically confirmed in 137 patients (12.0%), while jaundice (OR, 5.1; P < 0.001) and weight loss (OR, 2.0; P = 0.002) were independent predictors. Most resections were performed by open surgery (N = 847, 74.5%), while distal lesions were in majority treated using minimally invasive approaches (P < 0.001). Severe morbidity was 28.4% (N = 323) and 30d mortality was 2.6% (N = 29). Increased age (P = 0.004), higher BMI (P = 0.002), liver cirrhosis (P < 0.001), and esophageal varices (P = 0.002) were independent risk factors for 30d mortality.

CONCLUSION

With respect to unclear findings frequently present in PCL, diagnostic means recommended in guidelines should always be considered in the preoperative phase. The therapy of PCL should be decided upon in the light of patient-specific factors, and the surgical strategy needs to be adapted accordingly.

Current Status of the Diagnosis of Early-Stage Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) can be treated with surgery, chemotherapy, and radiotherapy. Despite medical progress in each field in recent years, it is still insufficient for managing PDAC, and at present, the only curative treatment is surgery. A typical pancreatic cancer is relatively easy to diagnose with imaging. However, it is often not recommended for surgical treatment at the time of diagnosis due to metastatic spread beyond the pancreas. Even if it is operable, it often recurs during postoperative follow-up. In the case of PDAC with a diameter of 10 mm or less, the 5-year survival rate is as good as 80% or more, and the best index for curative treatment is tumor size. The early detection of pancreatic cancer with a diameter of less than 10 mm or carcinoma in situ is critical. Here, we provide an overview of the current status of diagnostic imaging features and genetic tests for the accurate diagnosis of early-stage PDAC.

Functional Assessment of Cancer-Linked Mutations in Sensitive Regions of Regulators of G Protein Signaling Predicted by Three-Dimensional Missense Tolerance Ratio Analysis

Regulators of G protein signaling (RGS) proteins modulate G protein-coupled receptor (GPCR) signaling by acting as negative regulators of G proteins. Genetic variants in RGS proteins are associated with many diseases, including cancers, although the impact of these mutations on protein function is uncertain. Here we analyze the RGS domains of 15 RGS protein family members using a novel bioinformatic tool that measures the missense tolerance ratio (MTR) using a three-dimensional (3D) structure (3DMTR). Subsequent permutation analysis can define the protein regions that are most significantly intolerant (P < 0.05) in each dataset. We further focused on RGS14, RGS10, and RGS4. RGS14 exhibited seven significantly tolerant and seven significantly intolerant residues, RGS10 had six intolerant residues, and RGS4 had eight tolerant and six intolerant residues. Intolerant and tolerant-control residues that overlap with pathogenic cancer mutations reported in the COSMIC cancer database were selected to define the functional phenotype. Using complimentary cellular and biochemical approaches, proteins were tested for effects on GPCR-Gα activation, Gα binding properties, and downstream cAMP levels. Identified intolerant residues with reported cancer-linked mutations RGS14-R173C/H and RGS4-K125Q/E126K, and tolerant RGS14-S127P and RGS10-S64T resulted in a loss-of-function phenotype in GPCR-G protein signaling activity. In downstream cAMP measurement, tolerant RGS14-D137Y and RGS10-S64T and intolerant RGS10-K89M resulted in change of function phenotypes. These findings show that 3DMTR identified intolerant residues that overlap with cancer-linked mutations cause phenotypic changes that negatively impact GPCR-G protein signaling and suggests that 3DMTR is a potentially useful bioinformatics tool for predicting functionally important protein residues. SIGNIFICANCE STATEMENT: Human genetic variant/mutation information has expanded rapidly in recent years, including cancer-linked mutations in regulator of G protein signaling (RGS) proteins. However, experimental testing of the impact of this vast catalogue of mutations on protein function is not feasible. We used the novel bioinformatics tool three-dimensional missense tolerance ratio (3DMTR) to define regions of genetic intolerance in RGS proteins and prioritize which cancer-linked mutants to test. We found that 3DMTR more accurately classifies loss-of-function mutations in RGS proteins than other databases thereby offering a valuable new research tool.

Clinical and Molecular Attributes and Evaluation of Pancreatic Cystic Neoplasm

Intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are all considered "Pancreatic cystic neoplasms (PCNs)" and show a varying risk of developing into pancreatic ductal adenocarcinoma (PDAC). These lesions display different molecular characteristics, mutations, and clinical manifestations. A lack of detailed understanding of PCN subtype characteristics and their molecular mechanisms limits the development of efficient diagnostic tools and therapeutic strategies for these lesions. Proper in vivo mouse models that mimic human PCNs are also needed to study the molecular mechanisms and for therapeutic testing. A comprehensive understanding of the current status of PCN biology, mechanisms, current diagnostic methods, and therapies will help in the early detection and proper management of patients with these lesions and PDAC. This review aims to describe all these aspects of PCNs, specifically IPMNs, by describing the future perspectives.

Prospective, Multi-Institutional, Real-Time Next-Generation Sequencing of Pancreatic Cyst Fluid Reveals Diverse Genomic Alterations That Improve the Clinical Management of Pancreatic Cysts

BACKGROUND & AIMS

Next-generation sequencing (NGS) of pancreatic cyst fluid is a useful adjunct in the assessment of patients with pancreatic cyst. However, previous studies have been retrospective or single institutional experiences. The aim of this study was to prospectively evaluate NGS on a multi-institutional cohort of patients with pancreatic cyst in real time.

METHODS

The performance of a 22-gene NGS panel (PancreaSeq) was first retrospectively confirmed and then within a 2-year timeframe, PancreaSeq testing was prospectively used to evaluate endoscopic ultrasound-guided fine-needle aspiration pancreatic cyst fluid from 31 institutions. PancreaSeq results were correlated with endoscopic ultrasound findings, ancillary studies, current pancreatic cyst guidelines, follow-up, and expanded testing (Oncomine) of postoperative specimens.

RESULTS

Among 1933 PCs prospectively tested, 1887 (98%) specimens from 1832 patients were satisfactory for PancreaSeq testing. Follow-up was available for 1216 (66%) patients (median, 23 months). Based on 251 (21%) patients with surgical pathology, mitogen-activated protein kinase/GNAS mutations had 90% sensitivity and 100% specificity for a mucinous cyst (positive predictive value [PPV], 100%; negative predictive value [NPV], 77%). On exclusion of low-level variants, the combination of mitogen-activated protein kinase/GNAS and TP53/SMAD4/CTNNB1/mammalian target of rapamycin alterations had 88% sensitivity and 98% specificity for advanced neoplasia (PPV, 97%; NPV, 93%). Inclusion of cytopathologic evaluation to PancreaSeq testing improved the sensitivity to 93% and maintained a high specificity of 95% (PPV, 92%; NPV, 95%). In comparison, other modalities and current pancreatic cyst guidelines, such as the American Gastroenterology Association and International Association of Pancreatology/Fukuoka guidelines, show inferior diagnostic performance. The sensitivities and specificities of VHL and MEN1/loss of heterozygosity alterations were 71% and 100% for serous cystadenomas (PPV, 100%; NPV, 98%), and 68% and 98% for pancreatic neuroendocrine tumors (PPV, 85%; NPV, 95%), respectively. On follow-up, serous cystadenomas with TP53/TERT mutations exhibited interval growth, whereas pancreatic neuroendocrine tumors with loss of heterozygosity of ≥3 genes tended to have distant metastasis. None of the 965 patients who did not undergo surgery developed malignancy. Postoperative Oncomine testing identified mucinous cysts with BRAF fusions and ERBB2 amplification, and advanced neoplasia with CDKN2A alterations.

CONCLUSIONS

PancreaSeq was not only sensitive and specific for various pancreatic cyst types and advanced neoplasia arising from mucinous cysts, but also reveals the diversity of genomic alterations seen in pancreatic cysts and their clinical significance.

Pancreatic Cystic Lesions: A Focused Review on Cyst Clinicopathological Features and Advanced Diagnostics

Macroscopic, endomicroscopic, and histologic findings and correlation are an integral part of the diagnostic evaluation of pancreatic cystic lesions (PCLs), as complementing morphologic features seen by different specialties are combined to contribute to a final diagnosis. However, malignancy risk stratification of PCLs with worrisome features can still be challenging even after endoscopic ultrasound guided-fine needle aspiration (EUS-FNA) with cytological evaluation. This review aims to summarize cyst clinicopathological features from the pathologists' perspective, coupled with knowledge from advanced diagnostics-confocal laser endomicroscopy and cyst fluid molecular analysis, to demonstrate the state-of-art risk stratification of PCLs. This review includes illustrative photos of surgical specimens, endomicroscopic and histologic images, and a summary of cyst fluid molecular markers.