To explore the immune microenvironment of RAS‐mutated (RASmt) microsatellite stable (MSS) colon cancer (CC), we retrospectively performed whole exome sequencing, RNA sequencing, and robust digital pathology analyses and studied immune markers in a cohort of 161 patients treated with standard‐of‐care therapies with early stage disease (both fresh frozen and formalin‐fixed paraffin‐embedded [FFPE] samples) or 121 patients with metastatic setting (primary tumor FFPE samples). Only a small proportion of cases exhibited a highly infiltrated immune microenvironment, with a strong association between Immunoscore® (IS)‐high (13% of the samples) and Tumor Lymphocytes Infiltrating Score (TuLIS)‐high scores (25% of the samples). Immunoscore Immune‐Checkpoint (ISIC)‐high tumors (52% of the samples) shared a similar microenvironment composition to IS‐high and TuLIS‐like high tumors and displayed higher mutational burdens than ISIC‐low tumors. In conclusion, a substantial proportion of MSS RASmt CCs exhibit high ISIC scores, meriting evaluation in prospective trials of immunotherapy‐based combination regimens.

INTRODUCTION: Preoperative characterization of pancreatic cystic lesions (PCLs) remains inaccurate when based on morphology alone. We aimed to determine whether integrating complementary imaging (cross-sectional imaging plus endoscopic ultrasound) and clinical history, particularly history of pancreatitis, improves diagnostic accuracy compared with single-modality imaging. METHODS: This retrospective study included consecutive patients with PCLs treated at a tertiary referral center (test cohort) and a confirmatory cohort from a second hospital. Preoperative diagnostic accuracy was assessed in patients with histological confirmation. Multivariable logistic regression identified independent predictors of correct preoperative diagnosis. Additionally, a secondary multivariable logistic regression analysis included all patients using final diagnosis at follow-up (mean 2.4 ± 0.3 years) was performed. RESULTS: In the test cohort, 258 patients were analyzed; 59 (23%) had histological confirmation. Overall preoperative accuracy was 63% (validation cohort: 68%). No significant difference was observed between MRI, CT or endoscopic ultrasound alone. Complementary imaging was independently associated with higher diagnostic accuracy in multivariable analysis, as was main pancreatic duct dilation. In the full cohort, a history of acute or chronic pancreatitis was the only independent predictor of correct diagnosis and strongly predicted pseudocysts (80% vs. 10% without pancreatitis; p<0.00001). Combining complementary imaging with pancreatitis history further improved overall diagnostic accuracy and significantly increased detection of malignant PCLs compared with MRI alone (p=0.03). CONCLUSION: Diagnostic accuracy of PCLs is limited with single-modality imaging. A stepwise strategy integrating complementary imaging and clinical history, particularly a history of pancreatitis, significantly improves identification of malignant lesions and may refine guideline-based management.

Tumor-associated macrophages (TAMs) and monocytes that accumulate in colorectal cancer (CRC) play a crucial role in shaping the tumor microenvironment (TME) and anti-tumor immune responses. Although TAMs have been linked to both pro- and anti-tumor functions, our understanding of the cues instructing their heterogeneous phenotypes and function in cancer patients remains limited. Here, we established co-cultures comprising primary human monocytes and patient-derived organoids (PDOs) from patients with microsatellite-stable CRC to emulate myeloid/tumor cell interactions in vitro. Upon encountering PDOs, monocytes acquire phenotypic changes that are distinct from those induced by typical polarization protocols. Single-cell RNA sequencing revealed that PDO-exposed monocytes transcriptionally resembled IL1B-programmed monocytes previously identified in the tumor tissues of CRC patients. This phenotype emerged independently of tumor mutational profiles or consensus molecular subtypes. Mechanistically, soluble PDO-derived mediators induced the production of CXCL2, CXCL5 and CXCL7 chemokines, whereas the phagocytic uptake of tumor debris impaired the MHC class II-mediated antigen presentation capabilities of monocytes in co-culture. In addition, our in vitro system allowed functional assessment of PDO-exposed monocytes demonstrating a compromised capacity to mount an inflammatory response upon TLR stimulation. Together, PDO-monocyte co-cultures offer a platform to dissect the interplay between cancer cells and monocytes, and advance our understanding of myeloid plasticity and function in cancer patients.

BACKGROUND:Fluoropyrimidines + angiogenesis inhibitor or dose-reduced doublets are used for (frail) elderly patients with metastatic colorectal cancer (mCRC). This non-comparative trial evaluated two 1st line regimens for patients not eligible for full-dose combinations. METHODS:This open-label, multicenter, phase II study randomized untreated mCRC patients ≥ 70 years ± frailty 1:1 to dose reduced mFOLFOX7 in Arm A or aflibercept (4 mg/kg) plus dose reduced mLV5FU2 in Arm B. Primary endpoint was the 6-months PFS rate (PFS@6), secondary endpoints included safety, overall survival (OS), overall response rate (ORR), patient reported outcomes and overall treatment utility (OTU). FINDINGS:The full analysis population comprised 120 patients (62 Arm A, 58 Arm B; 63% male), with a median age of 78.5 years. 82% frail patients were included. PFS@6 was 68% [95%CI 56%;80%] in Arm A and 46% [32%;59%] in Arm B. Median PFS was 7.9 and 5.5 months, median OS was 20.4 and 19.0 months and ORR was 47% and 22% in Arm A and B, respectively. At 3 months, 52% in Arm A and 35% in Arm B had a good OTU. Most frequent grade ≥ 3 AEs in Arm B were hypertension (41%) and proteinuria (10%). More patients in arm B had treatment-related SAEs grade ≥ 3 (17% in arm B and 5% in arm A). INTERPRETATION:Both regimens were feasible in this (frail) elderly population. Dose-reduced mFOLFOX7 and, to a lesser extent, 5-FU/aflibercept showed good PFS and 3-month OTU. Although most patients were regarded frail, survival rates were promising, most likely due to effective further-line treatments.

Interindividual variability in response to cancer therapy is a major challenge in the management of colorectal cancer (CRC). The gut microbiome contributes to differential therapeutic efficacy and toxicity by modifying the pharmacokinetics and pharmacodynamics of anticancer drugs. Furthermore, bacterial products interact with tumor and immune cells, altering therapeutic outcomes. This review focuses on the impact of pharmacomicrobiomics on CRC therapy. We describe how gut microbiota affects drug metabolism on a mechanistic level and outline the interactions of specific microbes and their products with chemo-, targeted, and immunotherapies employed in CRC. Finally, we provide an overview of current strategies, including probiotics, engineered bacteria, and fecal microbiota transplantation, that exploit the gut microbiome to improve therapeutic efficacy and reduce toxicity.

Abstract Background AXIN1 is a central regulatory hub of many oncogenic pathways in colorectal cancer (CRC). As the main scaffold protein and least abundant component of the beta-catenin destruction complex, changes in AXIN1 levels tightly control Wnt signaling activity. How other cancer pathways beyond Wnt signaling regulate cellular AXIN1 levels is incompletely understood. Methods Colorectal cancer cell lines, murine and patient-derived intestinal and cancer organoids were used as model systems. Changes in AXIN1 levels upon drug perturbation were profiled by immunoblot, qPCR and RNA-seq. Ubiquitin-affinity immunoprecipitation assays and mass spectrometry were used to determine mechanisms of AXIN1 loss. To characterize effects on protein synthesis, we performed polysome and ribosome profiling (Ribo-seq). Results We show that targeting the Ras-MAPK pathway using clinically approved MEK1/2 inhibitors induces AXIN1 loss across a panel of CRC cell lines and patient-derived organoids. In contrast to GSK3 inhibitors, MEK1/2 inhibition neither affects protein stability nor post-translational modifications of AXIN1 and only caused a minor reduction of AXIN1 transcript levels. Co-treatment with tankyrase inhibitors could partially prevent loss of AXIN1 upon MEK1/2 inhibition. Using isogenic CRC cell lines and murine intestinal organoids, we show that APC truncations strongly reduce basal cellular AXIN1 levels, but do not alter dynamics of AXIN1 loss after MEK1/2 inhibition. Polysome profiling and Ribo-seq revealed that MEK1/2 inhibitors reduce global protein synthesis via an mTOR associated pathway. This translational repression is sufficient to cause significant AXIN1 loss, as treatment with mTOR or S6K inhibitors phenocopies the effect of MEK1/2 inhibitors. Conclusion Our study demonstrates that AXIN1 protein homeostasis is critically controlled by Ras-MAPK signaling at the level of protein synthesis, and that MEK1/2 inhibitors cause AXIN1 loss by global translational repression.

Background & Aims: Immunotherapy with atezolizumab and bevacizumab (a + b) has improved the prognosis of patients with unresectable hepatocellular carcinoma (HCC). However, the outcome for individual patients is highly variable. This study aimed to (i) develop and validate a prognostic prediction model to estimate individual prognosis and (ii) compare it with established models. Methods: In this multicenter retrospective study, patients with HCC undergoing first-line immunotherapy with a + b from 24 centers (Europe, USA) were included. Statistical analysis and reporting followed the TRIPOD guidelines. The primary objective was overall survival (OS). A Cox model was developed and externally validated. Results: In total, 683 patients were included (training: 526, validation: 157). The C-reactive protein, albumin, bilirubin, lymphocytes, ECOG performance status, and extrahepatic spread (CABLE score) remained significantly associated with OS in Cox regression analysis. In the training set, the CABLE score had a higher discriminatory accuracy relative to ALBI, EZ-ALBI, mALBI, CRAFITY, PNI, NLR, PLR, and GPS (time-dependent AUC 0.79 and C-index 0.75 (95% CI 0.71-0.78) at 12 months). In the external validation set, the discriminatory performance of the CABLE score was comparable to ALBI, EZ-ALBI, and mALBI, but on average higher than PNI, CRAFITY, NLR, PLR, and GPS. In patients with Child-Pugh A, the CABLE score outperformed ALBI, EZ-ALBI, and mALBI in the first 9 months. We provide a web-based calculator for the CABLE score to allow estimation of individual prognosis for these patients (http://shiny.imbei.uni-mainz.de:3838/CABLE_Score/). Conclusions: The CABLE score shows good discriminatory performance in assessing the individual prognosis of patients undergoing first-line immunotherapy with a + b. Further validation studies are needed to investigate its performance compared with the ALBI score, in particular in subgroup analysis. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Background Extraintestinal symptoms (EIS) in inflammatory bowel diseases, including fatigue, depression and anxiety, are highly prevalent, but poorly understood. Alterations of brain function may contribute to EIS, but their association with disease activity is unclear. This study analyzed intrinsic neural activity (INA) of individuals with Crohn's disease (CD) in different disease states and examined the relationship between INA and EIS.Methods Patients with CD (n = 92) and healthy controls (n = 41) underwent functional magnetic resonance brain imaging and completed symptom-specific psychometry. Temporal (amplitude of low-frequency fluctuations, ALFF) and spatial (regional homogeneity, ReHo) markers of INA were compared between CD and controls and between active (patients with active Crohn's disease [aCD]) versus remitted (rCD) disease. Regression analyses explored disease-state-dependent associations between INA and EIS.Results Patients exhibited aberrant INA in frontotemporal, occipital, and thalamic regions. Patients with aCD exhibited lower ALFF in left subcallosal cortex and inferior temporal gyri compared to rCD. Regional homogeneity in aCD was lower in left medial orbital gyrus and higher in right superior frontal, left inferior temporal, and left precentral gyrus. Compared to rCD, aCD showed higher ALFF predominantly in superior, ventro-, and dorsolateral prefrontal regions. Distinct associations between INA and EIS were detected in patients, particularly in the remitted state.Conclusions Intrinsic brain function in patients with CD varies by disease state, with prominent frontal cortex changes in active disease. These brain activity changes are at least partly related to the magnitude of neuropsychiatric symptoms and highlight a role of disturbed brain-gut interactions in the development of EIS especially in rCD. This study examined the intrinsic brain function of individuals with Crohn's disease in different disease states and healthy controls. Brain activity differed between patients and controls and between disease states and correlated with fatigue and depression in remitted disease only.