Malignant pleural mesothelioma (MPM) is a tumour associated with asbestos exposure. Approximately, 10% of patients with MPM carry a germline pathogenic variant (PV), mostly in DNA repair genes, suggesting the occurrence of inherited predispositions. This article aimed to 1) search for new predisposing genes and assess the prevalence of PVs in DNA repair genes, by next-generation sequencing (NGS) analysis of germline DNA from 113 unselected patients with MPM and 2) evaluate whether these patients could be sensitive to tailored treatments. NGS was performed using a custom panel of 107 cancer-predisposing genes. To investigate the response to selected drugs in conditions of DNA repair insufficiency, we created a three-dimensional-MPM cell model that had a defect in ataxia telangiectasia mutated (ATM), the master regulator of DNA repair. We identified PVs in approximately 7% of patients with MPM (8/113) and a new PV in BAP1 in a further patient with familial MPM. Most of these PVs were in genes involved or supposedly involved in DNA repair (BRCA1, BRIP1, CHEK2, SLX4, FLCN and BAP1). In vitro studies showed apoptosis induction in ATM-silenced/inhibited MPM spheroids treated with an enhancer of zeste homologue 2 inhibitor (tazemetostat). Overall these data suggest that patients with MPM and DNA repair insufficiency may benefit from this treatment, which induces synthetic lethality.

Growing evidence highlights the pivotal role of the gut microbiota in cancer development, progression, response to therapy, and survivorship. Diet plays a central role in shaping gut microbiota composition, influencing the immune system and overall host health. Plant-based diets and the Mediterranean diet promote health-associated microbial communities that increase the production of several metabolic-end products, including short-chain fatty acids that support mucosal barrier integrity, anti-inflammatory effects, and modulation of the immunity of the host. Conversely, Western dietary patterns promote cancer progression and negatively impact the response to standard treatments. Furthermore, gut microbiota influences the effectiveness of cancer therapies, including chemotherapy, radiotherapy and, mainly, immunotherapy. Modulating microbial species, their metabolites, or their activities in the cancer microenvironment through dietary interventions, common or engineered probiotics, prebiotics, postbiotics, antibiotics or fecal microbial transplant are emerging as promising strategies for cancer prevention and tailored management in survivorship. In this review, we explore the intricate interplay between diet, gut microbiota, and cancer, focusing on how specific microbial communities’ impact therapeutic outcomes, and the challenges in the modulation of the microbiota environment through several interventions, including diet. This emerging paradigm paves the way for integrating nutrition and microbiota-targeted strategies as innovative tools in the context of precision medicine.

According to the driver–passenger model for colorectal cancer (CRC), the tumor-associated microbiota is a dynamic ecosystem of bacterial species where bacteria with carcinogenic features linked to CRC initiation are defined as “drivers”, while opportunistic bacteria colonizing more advanced tumor stages are known as “passengers”. We reasoned that also gut microbiota-associated metabolites may be differentially enriched according to tumor stage, and be potential determinants of CRC development. Thus, we characterized the mucosa- and lumen-associated microbiota (MAM and LAM, respectively) and mucosa-associated metabolites in low- vs. high-grade dysplastic colon polyps from 78 patients. We show that MAM, obtained with a new biopsy-preserving approach, and LAM differ in composition and α/β-diversity. By stratifying patients for polyp histology, we found that bacteria proposed as passengers by previous studies colonized high-grade dysplastic adenomas, whereas driver taxa were enriched in low-grade polyps. Furthermore, we report altered “mucosa-associated metabolite” levels in low- vs. high-grade groups. Integrated microbiota-metabolome analysis suggests the involvement of the gut microbiota in the production and consumption of these metabolites. Altogether, our findings support the involvement of bacterial species and associated metabolites in CRC mucosal homeostasis in a tumor-stage-specific manner. These distinct signatures may be used to distinguish low-grade from high-grade dysplastic polyps.

Here, we aim to improve our understanding of various colorectal cancer (CRC) risk factors (obesity, unhealthy diet, and gut microbiota/metabolome alteration), analyzing 120 patients with colon polyps, divided in normal-weight (NW) or overweight/obese (OB). Dietary habits data (validated EPIC questionnaires) revealed a higher consumption of processed meat among OB vs. NW patients. Both mucosa-associated microbiota (MAM) on polyps and lumen-associated microbiota (LAM) analyses uncovered distinct bacterial signatures in the two groups. Importantly, we found an enrichment of the pathogenic species Finegoldia magna in MAM of OB patients, regardless of their polyp stage. We observed distinct mucosal-associated metabolome signatures, with OB patients showing increased pyroglutamic acid and reduced niacin levels, and performed microbiota-metabolome integrated analysis. These findings support a model where different risk factors may contribute to tumorigenesis in OB vs. NW patients, highlighting the potential impact of processed meat consumption and F. magna on CRC development among OB patients.

Malignant pleural mesothelioma (MPM) is a rare and aggressive neoplasm. Patients are usually diagnosed when current treatments have limited benefits, highlighting the need for noninvasive tests aimed at an MPM risk assessment tool that might improve life expectancy. Three hundred asbestos-exposed subjects (163 MPM cases and 137 cancer-free controls), from the same geographical region in Italy, were recruited. The evaluation of asbestos exposure was conducted considering the frequency, the duration and the intensity of occupational, environmental and domestic exposure. A genome-wide methylation array was performed to identify novel blood DNA methylation (DNAm) markers of MPM. Multiple regression analyses adjusting for potential confounding factors and interaction between asbestos exposure and DNAm on the MPM odds ratio were applied. Epigenome-wide analysis (EWAS) revealed 12 single-CpGs associated with the disease. Two of these showed high statistical power (99%) and effect size (>0.05) after false discovery rate (FDR) multiple comparison corrections: (i) cg03546163 in FKBP5, significantly hypomethylated in cases (Mean Difference in beta values (MD) = −0.09, 95% CI = −0.12|−0.06, p = 1.2 × 10⁻⁷), and (ii) cg06633438 in MLLT1, statistically hypermethylated in cases (MD = 0.07, 95% CI = 0.04|0.10, p = 1.0 × 10⁻⁶). Based on the interaction analysis, asbestos exposure and epigenetic profile together may improve MPM risk assessment. Above-median asbestos exposure and hypomethylation of cg03546163 in FKBP5 (OR = 20.84, 95% CI = 8.71|53.96, p = 5.5 × 10⁻¹¹) and hypermethylation of cg06633438 in MLLT1 (OR = 11.71, 95% CI = 4.97|29.64, p = 5.9 × 10⁻⁸) genes compared to below-median asbestos exposure and hyper/hypomethylation of single-CpG DNAm, respectively. Receiver Operation Characteristics (ROC) for Case-Control Discrimination showed a significant increase in MPM discrimination when DNAm information was added in the model (baseline model, BM: asbestos exposure, age, gender and white blood cells); area under the curve, AUC = 0.75; BM + cg03546163 at FKBP5. AUC = 0.89, 2.1 × 10⁻⁷; BM + cg06633438 at MLLT1. AUC = 0.89, 6.3 × 10⁻⁸. Validation and replication procedures, considering independent sample size and a different DNAm analysis technique, confirmed the observed associations. Our results suggest the potential application of DNAm profiles in blood to develop noninvasive tests for MPM risk assessment in asbestos-exposed subjects.