The development of colorectal cancer (CRC) is largely influenced by hereditary factors, with up to one-third of cases linked to genetic predisposition. In parallel, environmental factors such as diet and intestinal microbiota play a significant role. Lynch syndrome (LS), the most common form of hereditary CRC, is due to mutations in DNA mismatch repair genes. Diet interventions such as calorie restriction (CR) can modify the course of the disease, altering nutrient supply and promoting beneficial microbial populations. Fasting-mimicking diets (FMD) are plant-based CR regimens that showed promise in modulating the gut microbiota and suppressing CRC progression in pre-clinical ectopic cancer models. In this study, Villin-Cre/Msh2-floxed (VCM) mice, modelling LS, were subjected to periodic FMD cycles for 10 months. FMD regimen influenced animal weight in a sexually dimorphic manner, stably reducing animal body weight only in males. Moreover, shotgun metagenomic sequencing revealed that FMD mitigated the dysbiotic longitudinal changes associated with cancer onset, preserving beneficial species, such as Lactobacillus johnsonii, and reducing adverse species, such as Escherichia coli. Metabolic pathway analysis also showed significant differences, with FMD preventing the upregulation of pathways involved in amino acid and nucleotide synthesis, potentially promoting tumour growth. Overall, the findings suggest that periodic FMD may result useful in a multimodal approach for LS management, counteracting gut microbiota alterations.

Faecal microRNAs are promising molecular biomarkers for non-invasive colorectal cancer detection because of their stability in stool and disease-associated expression profiles. miR-451a is highly enriched in red blood cells and is therefore linked to erythrocyte-derived material associated with lesion-related bleeding. Here, we developed a direct chemiluminescent Dynamic Chemistry Labelling assay for miR-451a detection in a non-invasive colorectal cancer testing workflow. A chemiluminescent Dynamic Chemistry Labelling assay was developed for direct analysis of clarified stool lysates without RNA extraction, reverse transcription or enzymatic amplification. Analytical performance was evaluated using synthetic canonical miR-451a, abundant miR-451a isomiR variants and red blood cell spike-ins. Clinical performance was assessed in stool samples from 90 colonoscopy-characterised individuals, including 44 colorectal cancer cases and 46 colonoscopy-negative controls. Small RNA sequencing was used as an orthogonal comparison method. Group differences were assessed using non-parametric tests, agreement with sequencing data using Spearman correlation, and diagnostic performance using colonoscopy as the reference standard. The assay achieved a limit of detection of 4.25 pg/mL and a lower limit of quantification of 13 pg/mL. It detected canonical miR-451a and its abundant isomiR variants with sequence specificity. Red blood cell spike-in experiments confirmed detection of erythrocyte-derived miR-451a within the stool matrix, with the lowest quantifiable input corresponding to 1,689 red blood cells/µL. Using a predefined positivity threshold of 26 pg/mL, 36 of 44 colorectal cancer cases were miR-451a-positive and 36 of 46 colonoscopy-negative controls were miR-451a-negative, corresponding to 81.8% sensitivity and 78.3% specificity. Ten colonoscopy-negative controls were miR-451a-positive, whereas eight colorectal cancer cases were below the threshold. Dynamic Chemistry Labelling showed a positive association with small RNA sequencing and detected miR-451a in selected colorectal cancer samples with sequencing non-detection. This study establishes a direct PCR-free strategy for interrogating microRNAs in stool samples. miR-451a provides a sequence-defined molecular readout of erythrocyte-derived material and a CRC-relevant target suitable for stool-based nucleic acid testing. This approach provides a translational route toward future multiplexed faecal microRNA panels for colorectal cancer detection.

Psychosocial stress is a major risk factor for mental and physical illness, with emerging evidence pointing to oral microRNAs (miRNAs) and the microbiome as potential biomarkers. This study investigated stress-associated molecular changes in saliva from 113 male police officers stratified by perceived stress response (SR) into low, intermediate, or high responders. Salivary miRNA profiles were analyzed using small RNA sequencing, and microbiome composition was assessed through shotgun metagenomics. Eighteen miRNAs were dysregulated between high- and low-SR groups and reported a progressive alteration from low- to high-SR groups. Functional enrichment analysis indicated that dysregulated miRNA targets were involved in apoptosis, cellular stress responses, and metabolic regulation. Distinct alterations in salivary microbial communities were observed alongside SR levels. Functional analysis indicated enhanced inositol degradation and reduced pathways for L-tryptophan and thiamine biosynthesis in high-SR individuals. These findings suggest that salivary miRNAs and microbiota may serve as putative non-invasive biomarkers of psychosocial stress and provide insight into mechanisms linking chronic stress to physiological and behavioral outcomes.

The progression to critical COVID-19 arises predominantly from a dysregulated host immune response although the underlying regulatory mechanisms still remain partially elusive. This limits a prompt prediction of the disease progression, reduces the therapeutic options and restrains our understanding of “long COVID”. Here, we analyzed the transcriptome of peripheral blood mononuclear cells (PBMCs) collected from COVID-19 patients experiencing different degrees of the disease (mild and critical), and control patients enrolled in the clinical trial COntAGIouS as well as independent bulk RNA-seq, single-cell RNA-seq and proteomic datasets. In critical COVID-19 patients, the integrative analysis of transcriptomic data revealed an altered regulatory network involving microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and coding genes that control mRNA translation-related genes, epigenetics, and metabolism. In parallel, we observed an upregulation of tRNA aminoacylation genes in critical COVID-19 patients by the analysis of either bulk or single-cell RNA-seq data from publicly available independent cohorts. Additionally, we found increased expression of coding genes enriched for the cognate amino acids (glycine, alanine, isoleucine and tyrosine), all related to protein localization, post-translational modifications, and cell metabolism in our cohort. Similar alterations in amino acid frequency were found in an independent proteomic dataset. Collectively, our findings indicate a broad perturbation of the gene expression landscape that characterizes the aberrant host immune response in critical COVID-19 patients and is potentially coordinated by miRNA and tRNA metabolism alterations. COntAGIouS, NCT04327570. Registered 26 March 2020, https://clinicaltrials.gov/ct2/show/NCT04327570.

BACKGROUND:Large, prospective cohorts are needed to research the gut microbiome's role in colorectal cancer (CRC) risk. We evaluated the gut microbiome leveraging residual fecal immunochemical tests (FIT) from a CRC screening program in Turin, Italy, and conducted one of the largest population-based case-control studies across the adenoma-carcinoma sequence to date. METHODS:We extracted DNA from residual FIT stool, used whole-genome shotgun sequencing, and included those with CRC (N = 44), advanced adenomas (N = 269), early adenomas (N = 134), and FIT-negative controls (N = 478). Alpha diversity, beta diversity, and species, gene, and pathway relative abundances were estimated. Multivariable logistic regression models were used to estimate associations of these metrics with colorectal neoplasms. RESULTS:Alpha diversity was mostly inversely associated with colorectal neoplasms, particularly early adenomas (OR: 0.45, 95% CI: 0.25-0.80; P = 0.01). Presence of oral pathogens, including Parvimonas micra, was associated with higher odds of CRC. Furthermore, Escherichia coli and Bacteroides fragilis were strongly associated with higher odds of all colorectal neoplasms. Several genes and pathways were associated with colorectal neoplasms. CONCLUSIONS:Our findings align with smaller studies of the gut microbiome and colorectal neoplasms, supporting that CRC screening programs provide opportunities to prospectively study the gut microbiome's association with cancer risk in large populations.

Advanced Glycation Endproducts (AGEs) arise from the reaction of proteins with highly reactive dicarbonyl compounds such as methylglyoxal (MGO), glyoxal (GO) and 3-deoxyglucosone (3-DG), which have been implicated in inflammation and carcinogenesis. How dicarbonyls and AGEs are distributed across tumor tissue and surrogate specimens, and how they relate to systemic metabolism, AGE-related pathways, and alterations in gut microbiota in colon cancer, remains poorly understood. An integrative multi-specimen analysis of MGO, GO, 3-DG and major AGEs was performed using targeted tandem mass spectrometry in matched tumor tissue, adjacent normal mucosa, plasma, and stool from 26 sporadic colon cancer patients. These measurements were combined with tumor RNA-sequencing, untargeted plasma metabolomics, and stool shotgun metagenomics generated from the same individuals. A marked accumulation of MGO was observed in tumor tissue when compared with adjacent mucosa, accompanied by higher levels of the MGO-derived AGE Nδ-[5-hydro-5-methyl-4-imidazolon-2-yl]-ornithine (MG-H1). Tissue MG-H1 concentrations significantly correlated with corresponding plasma levels. Elevated tumor MGO levels were associated with up-regulation of GLO1 (encoding for the detoxifying enzyme glyoxalase-1), DDOST (coding for the AGE-clearance receptor AGE-R1), and the glycolytic flux marker triose phosphate isomerase (TPI), alongside down-regulation of the AGE-scavenger receptor CD36. These findings suggest a candidate remodeling of dicarbonyl-handling pathways. The MGO/GO ratio in tumors was positively associated with the relative abundances of Fusobacterium nucleatum and Parvimonas micra, two bacterial species related to colorectal carcinogenesis, and with metagenomic signatures of oral-derived taxa colonizing the gut. This pilot integrative analysis highlighted novel coherent associations among tissue, circulating, and stool levels of MGO-derived AGEs, the expression of AGE-related metabolic pathways, and microbial signatures in colon cancer. If confirmed in larger studies, these candidate molecular and microbial interactions may provide novel insights into the dicarbonyl stress involvement in tumor biology.

Diagnosis of inhalation injury (INHI) is invasive and subjective. Molecular biomarkers, such as microRNAs (miRNAs) in bronchoalveolar lavage (BAL; invasive) or urine (non-invasive) samples may help standardize the diagnosis. This study aimed to compare miRNA expression profiles in these two matrices from burn patients with INHI at two time points of hospitalization and to relate them to INHI severity. In this pilot prospective study, BAL and urine samples from burn patients with high-grade (HG) and low-grade (LG) INHI were collected on days 1 (immediately after injury) and 14 (after the acute effects had subsided) of hospitalization. The whole miRNome was investigated by next-generation sequencing. Expression of 34 miRNAs in BAL samples and 10 in urine differed between the two time points. Twelve BAL and eight urine miRNAs were overexpressed on day 1 compared to day 14. Eight miRNAs in BAL were linked with INHI severity: in particular, miR-34c-3p and miR-12136 were associated with HG INHI on day 1, but differences disappeared by day 14. No miRNAs in urine were associated with INHI severity. The association of miR-34c-3p with HG INHI in BAL confirms findings from an animal model, supporting its potential as a biomarker for HG INHI.

Psychosocial stress is a significant risk factor for mental and physical illness, and emerging evidence suggests that altered oral microRNAs (miRNAs) and microbiome may act as biomarkers or mediators of stress responses.This study investigated stress-associated molecular changes in saliva from 113 male police officers. Based on repeated administrations of the Karasek Demand/Control and Effort/Reward Imbalance questionnaires, subjects were stratified by perceived stress response (SR) to homogeneous occupational stressors into low, intermediate, or high responders. Salivary miRNA profiles were analyzed using small RNA sequencing, and microbiome composition was assessed through shotgun metagenomics.Eighteen miRNAs were significantly differentially expressed between high- and low-SR groups, with four miRNAs with increasing (miR-10400-5p, miR-1290, miR-6074-5p, and miR-9902) and fourteen with decreasing (including miR-21-5p and mirR-142-3p) levels in the high SR group (adj.p<0.05). The identified salivary miRNAs showed a progressive alteration from low- to high-SR groups. Functional enrichment analysis indicated that dysregulated miRNA targets are involved in apoptosis, cellular stress responses, and metabolic regulation.Distinct salivary microbial communities were also observed across SR groups. Several taxa displayed progressive abundance shifts, with Prevotella baroniae and Schaalia odontolytica increasing and Actinomyces naeslundii and Capnocytophaga ochracea decreasing in the high SR group. Functional predictions revealed, in this group, a significant enrichment of inositol degradation pathways, paralleled by a reduction in bacteria involved in L-tryptophan and thiamine biosynthesis.These findings suggest that salivary miRNAs and microbiota profiles may serve as non-invasive biomarkers of psychosocial stress and provide insight into molecular mechanisms linking chronic stress to physiological and behavioral outcomes.

We are delighted to share with you our fifteenth Journal Club and highlight some of the most interesting papers published recently [...].

BACKGROUND:MicroRNAs (miRNAs) have been proposed as diagnostic biomarkers of asbestos-related cancers, but their role in asbestos-related interstitial lung diseases (ILDs) is unknown. RESEARCH DESIGN AND METHODS:We conducted a pilot study in 30 subjects: 11 unexposed population controls, 8 ILD-free asbestos-exposed subjects, and 11 asbestos-related ILD cases. We used the Receiver Operator Characteristic (ROC) Area Under the Curve (AUC) to estimate the diagnostic accuracy of miRNAs, and volcano plots to assess their differential expression between the study groups. RESULTS:miR-548h-5p was over-expressed in ILD-free asbestos-exposed subjects and demonstrated a 90% accuracy (95% CI: 0.75-1.00) in discriminating them from unexposed subjects, as well as a 96% diagnostic accuracy (95% CI: 0.88-1.00) in differentiating asbestos-related ILD cases from ILD-free asbestos-exposed subjects. miR-6127-3p was over-expressed and showed an accuracy of 85% (95% CI: 0.66-1.00) in discriminating asbestos-related ILD cases from unexposed subjects in plasma. let-7f-5p was over-expressed in the exhaled breath condensate (EBC) of ILD-free asbestos-exposed subjects and showed a 90% accuracy (95% CI: 0.76-1.00) in discriminating them from unexposed subjects. CONCLUSIONS:Our results suggest that the plasma and EBC miRNA profile might serve as a diagnostic biomarker of asbestos-related ILDs.

Early detection of colorectal cancer (CRC) significantly improves its management and patients’ survival. Circular RNAs (circRNAs) are peculiar covalently closed transcripts involved in gene expression modulation whose dysregulation has been extensively reported in CRC cells. However, little is known about their alterations in the early phases of colorectal carcinogenesis. In this study, we performed an integrative analysis of circRNA profiles in RNA-sequencing (RNA-Seq) data of 96 colorectal cancers, 27 adenomas, and matched adjacent mucosa tissues. We also investigated the levels of cognate linear transcripts and those of regulating RNA-binding proteins (RBPs). Levels of circRNA-interacting microRNAs (miRNAs) were explored by integrating data of small RNA-Seq performed on the same samples. Our results revealed a significant dysregulation of 34 circRNAs (paired adj. p < 0.05), almost exclusively downregulated in tumor tissues and, prevalently, in early disease stages. This downregulation was associated with decreased expression of circRNA host genes and those encoding for RBPs involved in circRNA biogenesis, including NOVA1, RBMS3, and MBNL1. Guilt-by-association analysis showed that dysregulated circRNAs correlated with increased predicted activity of cell proliferation, DNA repair, and c-Myc signaling pathways. Functional analysis showed interactions among dysregulated circRNAs, RBPs, and miRNAs, which were supported by significant correlations among their expression levels. Findings were validated in independent cohorts and public datasets, and the downregulation of circLPAR1(2,3) and circLINC00632(5) was validated by ddPCR. These results support that multiple altered regulatory mechanisms may contribute to the reduction of circRNA levels that characterize early colorectal carcinogenesis.

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide, but large screening programs can effectively reduce both incidence and mortality. Fecal immunochemical test (FIT) is widely used in CRC screening programs and cost-effective. However, FIT test shows a low sensitivity for advanced adenomas (AA) and is also prone to false positive results, resulting in unnecessary total colonoscopies (TC). Leftover from FIT samples after hemoglobin measurement may offer unique opportunity to study alternative biomarkers, which may allow adopting a tailored screening approach. Altered miRNA profiles can be detected non-invasively in fecal samples. Our group studying the whole miRNome in stool recently contributed to the identification of a miRNA signature that accurately discriminates sporadic CRC at diagnosis (Pardini et al, Gastroenterology 2023) and demonstrated the feasibility of miRNA profiling in FIT leftovers (Birkeland et al. Mol Cancer 2023). However, a potential implementation of miRNA markers in FIT-based screening has not been fully explored. The aim of the study was to investigate the association of miRNA expression profiles with CRC or adenomas as well as the predictivity of miRNA signatures for outcomes at the subsequent screening round among screens examined within the population-based screening program in Turin, Italy. Small RNA sequencing was performed on leftover FIT samples of 438 subjects: 183 FIT positive (FIT+) detected with colorectal neoplasm (45 early adenomas, 110 AA, and 28 CRC), 93 with FIT+ and negative TC and 162 FIT negative (FIT-) controls. We compared the miRNA expression profiles of FIT+ screens with a negative TC and of those detected with neoplasia. For a subset of 213 subjects with a negative FIT at the previous round, we compared the miRNA profile at the first sample among screens with persistent negative results with those with a positive FIT and neoplasms. An average of 691 miRNAs were detected and 198 among them identified in more than 90% of the samples. Differential expression analyses between FIT+ and FIT- samples showed 379 miRNAs with significantly different levels (adj. p<0.05), mainly in AA or CRC. Notably, the previously identified 5-miRNA signature in stool was confirmed able to distinguish in FIT+ subjects with AA or CRC with respect to FIT-. miR-1246 was able to distinguish also subjects with neoplasm from those with negative TC. An increase of miR-1246 levels was observed in leftover samples of subjects at first round of screening who were detected AA or CRC following a positive FIT result at second round with respect to those with FIT- test. The previously identified miRNA signature shows a good performance in discriminating subject with neoplasm within FIT+ subjects. Further analyses to investigate the performance of various miRNA sets according to different FIT levels or screening rounds are ongoing. Barbara Pardini, Giulio Ferrero, Sara Bulfamante, Sonia Tarallo, Giulia Francescato, Davide Ricupero, Gianluigi Ferrante, Carlo Senore, Alessio Naccarati. Profiling microRNAs in fecal immunochemical test leftover buffer to improve colorectal cancer screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2342.

Background High sodium intake is associated with arterial hypertension and cardiovascular disease, through mechanisms that go beyond hemodynamic changes, including endothelial dysfunction, oxidative stress, and induction of a proinflammatory milieu. The aim of this study was to assess the role of dietary sodium modulation on renal pathophysiology through evaluation of small RNA cargos on urinary extracellular vesicles. Methods Fourteen high‐risk normotensive subjects with normal kidney function were prospectively enrolled to undergo a low‐sodium diet followed by a high‐sodium diet (HSD). The urinary extracellular vesicles were isolated from a 24‐hour urine collection at the end of each diet phase and profiled by small RNA sequencing. Selected differentially expressed miRNAs were validated in human proximal tubular cell line (human kidney 2 cells) to assess miRNA‐mRNA target interactions. Results We identified 111 small RNA species, of which 30 were significantly different between the low‐sodium diet and HSD. Bioinformatic network analysis showed that pathways related to the innate and adaptive immune system, interleukin and interferon signaling were enriched in the HSD, whereas pathways related to PPARα (peroxisome proliferator‐activated receptor α) regulation were enriched in the low‐sodium diet. In human kidney 2 cells, the inhibition of miR‐320b, downregulated in the HSD, increased ICAM‐1 (intercellular adhesion molecule 1), with renal proinflammatory effects. The inhibition of miR‐10b‐5p, downregulated in the low‐sodium diet, increased PPARα, which has an antifibrotic and anti‐inflammatory role in the kidney. Conclusions Small RNA characterization from extracellular vesicles revealed that an HSD is associated with proinflammatory changes, potentially contributing to sodium‐induced low‐grade renal inflammation.

Associations between the gut microbiome and colorectal cancer (CRC) have been uncovered, but larger and more diverse studies are needed to assess their potential clinical use. We expanded upon 12 metagenomic datasets of patients with CRC (n = 930), adenomas (n = 210) and healthy control individuals (n = 976; total n = 2,116) with 6 new cohorts (n = 1,625) providing granular information on cancer stage and the anatomic location of tumors. We improved CRC prediction accuracy based solely on gut metagenomics (average area under the curve = 0.85) and highlighted the contribution of 19 newly profiled species and distinct Fusobacterium nucleatum clades. Specific gut species distinguish left-sided versus right-sided CRC (area under the curve = 0.66) with an enrichment of oral-typical microbes. We identified strain-specific CRC signatures with the commensal Ruminococcus bicirculans and Faecalibacterium prausnitzii showing subclades associated with late-stage CRC. Our analysis confirms that the microbiome can be a clinical target for CRC screening and characterizes it as a biomarker for CRC progression.

Objective: The high morbidity and mortality associated with colorectal cancer (CRC) and the recent increases in early-onset CRC obviate the need for novel methods to detect and treat this disease, particularly at early stages. We hypothesize that aberrant expression of genes involved in the crypt-luminal migration of colon epithelial cells, a process necessary for their growth arrest and maturation, may disrupt differentiation and transition cells from a normal to tumorigenic state. Methods: We searched for contractility- and motility-related genes that are dysregulated in human CRC relative to normal colon. RNA expression of one such gene, tropomyosin 4 (TPM4), was measured by qRT-PCR and RNA-seq in human colorectal tissues at various stages of tumorigenesis: CRC, adenoma, and at-risk (grossly normal mucosa from a patient with Familial Adenomatous Polyposis, or FAP), relative to controls. Effects of aberrant TPM4 expression on colon epithelial cell proliferation and maturation were determined by overexpression using stable transfection in spontaneously differentiating Caco2 cells or silencing using siRNA in proliferating cells. Results: TPM4 is overexpressed at various stages of tumorigenesis, including CRC, adenoma, and grossly normal FAP colon tissue, as well as in proliferating versus differentiating Caco2 cells. TPM4.2 overexpression in differentiating Caco2 cells markedly inhibits certain aspects of maturation, notably sucrase isomaltase and glutathione-S-transferase alpha1 expression, and causes morphological and cell junction abnormalities. Conversely, siRNA-mediated suppression of TPM4.2 inhibits Caco2 proliferation. Conclusions: TPM4 overexpression attenuates colon epithelial cell differentiation and promotes proliferation. Therefore, TPM4 expression may be a biomarker to enhance strategies for CRC diagnosis and treatment.

Colorectal cancer (CRC) is the third most common and lethal cancer type worldwide. Although CRC incidence in the older population has decreased in many countries, early-onset CRC cases (< 50 years age, EOCRC) have been rapidly increasing globally. The fecal microbiome has been reproducibly associated with CRC. However, microbiome differences according to age of onset, stage, anatomic location, and genomic instability remain only minimally explored. Here, we integrated data generated from the ONCOBIOME consortium, Cancer Grand Challenges PROSPECT project and the ARETHUSA study, providing seven new cohorts of gut microbiome samples from healthy, adenoma- and CRC individuals (n total = 1, 668) combined with 12 public studies, for a total of 3, 784 metagenomic samples, including 190 EOCRC and 270 age-matched control samples. Information on tumor stage, anatomic location, microsatellite stability/instability-high (MSS/MSI-H) has been curated and harmonized across datasets. Metagenomes were analyzed using the bioBakery suite for community-, species-, strain-level, and gene-level profiling, and downstream integrative analysis was performed via meta-analysis and leave-one-dataset-out learning tasks. We obtained increased microbiome-based CRC prediction capabilities (average leave-one-dataset-out AUC = 0.84) and accurate species- and strain-level characterization of CRC stages (e.g., Slackia exigua and Ruminococcus bicirculans, respectively, between stage 0-II and III/IV), while the microbiome in adenoma samples did not differ substantially from controls (average leave-one-dataset-out AUC < 0.6). The fecal microbiome of right-sided CRC cases presented lower species and higher oral commensals richness than left-sided cases. The gut microbiome composition of MSI-H CRC was significantly different than MSS, as reflected by machine learning discrimination performances (average cross-validation AUC = 0.71), and characterized by reduced alpha-diversity and fewer biomarkers than in MSS cases, such as Ligilactobacillus salivarius and Limosilactobacillus fermentum. We confirmed that EOCRC microbiome was significantly different from age-matched controls (average leave-one-dataset-out AUC = 0.84), harboring typical CRC-associated bacteria, such as F. nucleatum and D. pneumosintes. Overall, we defined cross-cohort reproducible microbiome associations across tumor stages, primary location, genetic instability, and EOCRC, providing improved resolution within the CRC microbiome and more refined targets for diagnosis and therapeutic stratification. Gianmarco Piccinno, Kelsey N. Thompson, Paolo Manghi, Luca Lazzari, Chiara Pozzi, Andrew R. Ghazi, Andrew M. Thomas, Aitor Blanco-Miguez, Francesco Asnicar, Katarina Mladenovic, Federica Pinto, Federica Armanini, Giulio Ferrero, Sonia Tarallo, Long H. Nguyen, Yan Yan, Mingyang Song, Veronika Vymetalkova, Mario Trompetto, Vaclav Liska, Tomas Hucl, Pavel Vodicka, Beatrix Bencsiková, Martina Čarnogurská, Vlad Popovici, Salvatore Siena, Andrea Sartore-Bianchi, Michela Lizier, Carmen Correale, Alessandra Raimondi, Filippo Pietrantonio, Federica Marmorino, Chiara Cremolini, Barbara Pardini, Francesca Cordero, Lisa Derosa, Silvia Marsoni, Alberto Bardelli, Maria Rescigno, Yin Cao, Andrew T. Chan, Laurence Zitvogel, Curtis Huttenhower, Alessio Naccarati, Eva Budinska, Nicola Segata. Microbiome alterations of colorectal cancer according to age of onset, stage, anatomic location, and mismatch repair deficiency. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2370.

The field of non-coding RNA research is advancing at a breathtaking pace, continually uncovering new layers of regulatory complexity and functional diversity [...]

The diagnostic performance of molecular markers in surrogate tissues like stool may be affected by colorectal cancer (CRC) morphological heterogeneity. The mucinous histotype represents a subgroup of CRC with a peculiar molecular program and unfavorable disease progression. However, the percentage of mucinous morphology necessary to define this subtype is still a matter of debate. In this study, we investigated whether stool miRNA profiles of CRC patients differ in patients with mucinous histopathological subtypes compared to non-mucinous cancers. In this respect, we also explored how the stool miRNA signature reported in our previous multicentric study behaves in this histotype. Small-RNA sequencing was performed in fecal and tissue samples of an Italian cohort (n = 172), including 27 CRC with mucinous morphology (mucinous cancers with ≥ 50% mucinous morphology and those with mucinous component ≥ 5% but < 50%), 58 non-mucinous CRC, and 87 colonoscopy-negative controls. Results were compared with fecal miRNA profiles of a cohort from the Czech Republic (n = 98). Most of the differentially expressed (DE) stool miRNAs (n = 324) were in common between CRC with mucinous morphology and non-mucinous histopathological subtypes in comparison with healthy controls. Interestingly, the altered levels of 25 fecal miRNAs previously identified distinguishing CRC cases from controls in both cohorts were also confirmed after stratification for mucinous morphology. Forty-nine miRNAs were DE exclusively in CRC with mucinous morphology and 61 in non-mucinous CRC. Mucinous cancers and those with mucinous component showed fairly similar profiles that were comparable in the Czech cohort. Among the stool DE miRNAs observed in CRC with mucinous morphology, 20 were also altered in the comparison between tumor and adjacent mucosa tissue. This study highlights miRNAs specifically altered in CRC with mucinous morphology. Nevertheless, the performance of our stool miRNA signature in accurately distinguishing CRC cases from controls was not significantly affected by this histological subtype. This aspect further supports the use of stool miRNAs for noninvasive diagnosis and screening strategies.