Pancreatic ductal adenocarcinoma is one of the most lethal malignant diseases, with a mortality rate being close to incidence. Due to its heterogeneity and plasticity, as well as the lack of distinct symptoms in the early phases, it is very often diagnosed at an advanced stage, resulting in poor prognosis. Traditional tissue biopsies remain the gold standard for making a diagnosis, but have an obvious disadvantage in their inapplicability for frequent sampling. Blood-based biopsies represent a non-invasive method which potentially offers easy and repeated sampling, leading to the early detection and real-time monitoring of the disease and hopefully an accurate prognosis. Given the urgent need for a reliable biomarker that can estimate a patient’s condition and response to an assigned treatment, blood-based biopsies are emerging as a potential new tool for improving patients’ survival and surveillance. In this article, we discuss the current advances and challenges in using liquid biopsies for pancreatic cancer, focusing on circulating tumour DNA (ctDNA), extracellular vesicles (EVs), and circulating tumour cells (CTCs), and compare the performance and reliability of different biomarkers and combinations of biomarkers.

Pancreatic ductal adenocarcinoma (PDAC) represents a formidable challenge due to its aggressive nature and poor prognosis. The tumor microenvironment (TME) in PDAC, characterized by intense stromal desmoplastic reactions and a dominant presence of cancer-associated fibroblasts (CAFs), significantly contributes to therapeutic resistance. However, within the heterogeneous CAF population, fibroblast activation protein (FAP) emerges as a promising target for Gallium-68 FAP inhibitor positron emission tomography (Ga68FAPI-PET) imaging. Notably, 68Ga-FAPI-PET demonstrates promising diagnostic sensitivity and specificity, especially in conjunction with low tracer uptake in non-tumoral tissues. Moreover, it provides valuable insights into tumor–stroma interactions, a critical aspect of PDAC tumorigenesis not adequately visualized through conventional methods. The clinical implications of this innovative imaging modality extend to its potential to reshape treatment strategies by offering a deeper understanding of the dynamic TME. However, while the potential of 68Ga-FAPI-PET is evident, ongoing correlative studies are essential to elucidate the full spectrum of CAF heterogeneity and to validate its impact on PDAC management. This article provides a comprehensive review of CAF heterogeneity in PDAC and explores the potential impact of 68Ga-FAPI-PET on disease management.

Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with poor prognosis. Gemcitabine is the first-line therapy for PDAC, but gemcitabine resistance is a major impediment to achieving satisfactory clinical outcomes. This study investigated whether methylglyoxal (MG), an oncometabolite spontaneously formed as a by-product of glycolysis, notably favors PDAC resistance to gemcitabine. We observed that human PDAC tumors expressing elevated levels of glycolytic enzymes together with high levels of glyoxalase 1 (GLO1), the major MG-detoxifying enzyme, present with a poor prognosis. Next, we showed that glycolysis and subsequent MG stress are triggered in PDAC cells rendered resistant to gemcitabine when compared with parental cells. In fact, acquired resistance, following short and long-term gemcitabine challenges, correlated with the upregulation of GLUT1, LDHA, GLO1, and the accumulation of MG protein adducts. We showed that MG-mediated activation of heat shock response is, at least in part, the molecular mechanism underlying survival in gemcitabine-treated PDAC cells. This novel adverse effect of gemcitabine, i.e., induction of MG stress and HSR activation, is efficiently reversed using potent MG scavengers such as metformin and aminoguanidine. We propose that the MG blockade could be exploited to resensitize resistant PDAC tumors and to improve patient outcomes using gemcitabine therapy.

Background: A resemblance of pancreatic tumours to their native tissue architecture remains largely unexplored, while it may reveal novel insights into healthy and diseased tissue. Objective: This study aims at generating a spatially resolved map of human pancreatic duct cell populations in the native tissue and in tumours, that is, pancreatic ductal adenocarcinoma (PDAC) and adenosquamous carcinoma of the pancreas (ASCP). Design: New datasets were acquired with several spatial transcriptomics platforms integrated with public single-cell RNAseq datasets and validated by multiplex immunofluorescence. Cell lines and primary human cell cultures were genetically manipulated. Results: Groups of Keratin-5 ⁺ cells in larger ducts have a gene signature reminiscent of stem cells and (supra)basal cells from other tissues. At single cell resolution, this group comprises ∆Np63 ⁺ basal cells (BAS) and ∆Np63 ⁻ supra-basally residing luminal-B cells (LUM-B). The latter express previously unreported MUC4 and MUC16 and are distinct from other luminal cells in the ducts. In cancer, BAS and LUM-B signatures associate with basal-like (BL) PDAC and correlate with lower survival. However, PDAC exhibits a random spatial pattern and fragmented native expression programmes while ASCP preserves the identity of LUM-B and BAS in a spatially unmixed pattern. ∆Np63 drives cell plasticity to BAS, conserved from the native tissue to cancer. Conclusion: Spatially distinct duct cell populations are revealed, and the extent of preservation of the native cell identities in pancreatic cancer underpins distinct tumour identities. This warrants separate consideration in research and therapy.

Purpose Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive malignancies, largely due to chemoresistance arising from prominent cellular heterogeneity and a complex tumor microenvironment. Given this challenge, understanding the mechanisms of driving chemoresistance is essential for guiding our chemotherapeutic choice. Emerging evidence suggests that methylglyoxal (MG), a reactive glycolytic byproduct, may play a role in modulating tumor behavior and therapy response, offering a novel angle for patient stratification. Our recent study indicates that the accumulation of MG in PDAC cells leads to MG-induced cellular stress associated with gemcitabine (GEM) resistance. The primary objective of this study was to identify a predictive transcriptomic signature associated with MG stress in PDAC and compare it to the recently reported GemPred signature. Patients and methods MG stress classification was applied to the Puleo et al. cohort (n=309), enabling differential gene expression analysis and the development of a prognostic 16-gene MG-GEM signature through LASSO Cox regression. The signature was validated for survival prediction and diagnostic performance using cross-validation and ROC analysis. Results The prognostic significance and predictive performance of the signature were validated in both internal and external cohorts, including this from the phase III PRODIGE-24/CCTG PA6 trial, composed of 167 GEM and 183 FOLFIRINOX (mFFX) patients. Importantly, the MG-GEM signature demonstrated independent and complementary predictive value relative to GemPred. Conclusion We present a novel clinically actionable 16-gene transcriptomic signature reflecting MG-induced stress that enables robust stratification of PDAC patients likely to benefit from adjuvant GEM therapy. This model supports the development of personalized treatment strategies in pancreatic cancer. Key Objective Can metabolic gemcitabine (GEM) resistant inducer methylglyoxal stress be used to predict resistance to adjuvant GEM through a transcriptomic signature? Knowledge Generated The transcriptomic MG-GEM signature demonstrated the ability to distinguish between GEM sensitive and GEM resistant patients in the internal cohorts from Erasme University Hospital. MG-GEMs predictive capacity was further validated in the independent PRODIGE-24/CCTG PA6 clinical trial data. When compared to the established GemPred transcriptomic signature, MG-GEM exhibited an independent predictive behaviour. Moreover, combining both independent signatures enhanced the identification of GEM sensitive and GEM resistant patient subgroups. This combined approach may be particularly valuable in identifying patient subsets with treatment- specific responses.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest tumors with slow progress in systemic therapies due to its peculiar and resistant tumor microenvironment. Inclusion of isotoxic high-dose stereotactic body radiation therapy (iHD-SBRT) into a total neoadjuvant strategy (TNT) is promising for the treatment of localized PDAC. However, the histo-molecular effects of iHD-SBRT are still poorly explored. In this study, we have shown that TNT, associating FOLFIRINOX [FFX] followed by iHD-SBRT, leads to significant and long-lasting remodeling of PDAC, affecting its stromal, metabolic, and molecular features. Contrary to FFX alone, TNT is able to enrich tumors with Classical and Inactive stromal signatures associated with better prognosis. Furthermore, iHD-SBRT seems capable to counteract several of the detrimental modulatory effects induced by FFX such as Epithelial-to-Mesenchymal Transition or angiogenesis. Additionally, we identified inflammatory cancer-associated fibroblasts signatures as an important prognostic factor. This work provides new rationale to sequentially combine FFX with iHD-SBRT and suggests new pathways that can be targeted in combination with a TNT.