Diet-driven microbial ecology underpins associations between cancer immunotherapy outcomes and the gut microbiome

Biomarker-Driven Personalization of Neoadjuvant Immunotherapy in Melanoma

The introduction of immunotherapy has ushered in a new era of anticancer therapy for many cancer types including melanoma. Given the increasing development of novel compounds and combinations and the investigation in earlier disease stages, the need grows for biomarker-based treatment personalization. Stage III melanoma is one of the front-runners in the neoadjuvant immunotherapy field, facilitating quick biomarker identification by its immunogenic capacity, homogeneous patient population, and reliable efficacy readout. In this review, we discuss potential biomarkers for response prediction to neoadjuvant immunotherapy, and how the neoadjuvant melanoma platform could pave the way for biomarker identification in other tumor types.

SIGNIFICANCE

In accordance with the increasing rate of therapy development, the need for biomarker-driven personalized treatments grows. The current landscape of neoadjuvant treatment and biomarker development in stage III melanoma can function as a poster child for these personalized treatments in other tumors, assisting in the development of new biomarker-based neoadjuvant trials. This will contribute to personalized benefit-risk predictions to identify the most beneficial treatment for each patient.

16S rDNA profiling of Loach (Misgurnus anguillicus) fed with soybean fermented powder intestinal flora in response to Lipopolysaccharide (LPS) infection

Soybean fermentation has a balancing effect on the regulation of intestinal flora. Relative research between fermented soybeans and intestinal microbiota is limited. Our aim was to explore the effects of soybean fermented fowder on lipopolysaccharide (LPS) induced intestinal microflora and corresponding functions in loach. 16S rDNA high-throughout sequencing was applied to estimate differences in the intestinal microbiota and predict genes function. Analysis of the overall of sequencing data showed that the ratio of Effective Tags in both the control group and the treatment group was greater than 80 %. Based on six major classifications involved in the phylum, class, order, family, genus, and species, we acquired the changes in the composition of intestinal microorganisms after the supplement of soybean fermented powder. These results showed that the dominant bacteria in the two groups were basically distinct at different levels. Alpha diversity analysis indicated that the microbial richness and uniformity of soybean fermented powder decreased compared to the control group. PICRUSt and Taxfun tools analysis of intestinal flora illustrated the functional genes of the six groups were mainly involved in metabolism, genetic information processing, cellular processes, environmental information processing, and human diseases at the level 1. These data clearly demonstrated the effect of soybean fermented powder on the gut microbiome. Not only that, it provides new ideas and insights for achieving high-quality utilization of soybean fermented powder. The potential mechanisms of soybean fermented powder to alter gut flora and intestinal microbiome function can further be explored.

Dysbiotic Gut Microbiota-Derived Metabolites and Their Role in Non-Communicable Diseases

Dysbiosis, generally defined as the disruption to gut microbiota composition or function, is observed in most diseases, including allergies, cancer, metabolic diseases, neurological disorders and diseases associated with autoimmunity. Dysbiosis is commonly associated with reduced levels of beneficial gut microbiota-derived metabolites such as short-chain fatty acids (SCFA) and indoles. Supplementation with these beneficial metabolites, or interventions to increase their microbial production, has been shown to ameliorate a variety of inflammatory diseases. Conversely, the production of gut 'dysbiotic' metabolites or by-products by the gut microbiota may contribute to disease development. This review summarizes the various 'dysbiotic' gut-derived products observed in cardiovascular diseases, cancer, inflammatory bowel disease, metabolic diseases including non-alcoholic steatohepatitis and autoimmune disorders such as multiple sclerosis. The increased production of dysbiotic gut microbial products, including trimethylamine, hydrogen sulphide, products of amino acid metabolism such as p-Cresyl sulphate and phenylacetic acid, and secondary bile acids such as deoxycholic acid, is commonly observed across multiple diseases. The simultaneous increased production of dysbiotic metabolites with the impaired production of beneficial metabolites, commonly associated with a modern lifestyle, may partially explain the high prevalence of inflammatory diseases in western countries.

The impact of the gut microbiome on tumor immunotherapy: from mechanism to application strategies

Immunotherapy is one of the fastest developing areas in the field of oncology. Many immunological treatment strategies for refractory tumors have been approved and marketed. Nevertheless, much clinical and preclinical experimental evidence has shown that the efficacy of immunotherapy in tumor treatment varies markedly among individuals. The commensal microbiome mainly colonizes the intestinal lumen in humans, is affected by a variety of factors and exhibits individual variation. Moreover, the gut is considered the largest immune organ of the body due to its influence on the immune system. In the last few decades, with the development of next-generation sequencing (NGS) techniques and in-depth research, the view that the gut microbiota intervenes in antitumor immunotherapy through the immune system has been gradually confirmed. Here, we review important studies published in recent years focusing on the influences of microbiota on immune system and the progression of malignancy. Furthermore, we discuss the mechanism by which microbiota affect tumor immunotherapy, including immune checkpoint blockade (ICB) and adoptive T-cell therapy (ACT), and strategies for modulating the microbial composition to facilitate the antitumor immune response. Finally, opportunity and some challenges are mentioned to enable a more systematic understanding of tumor treatment in the future and promote basic research and clinical application in related fields.

Modulation of gut microbiota: a novel approach to enhancing the effects of immune checkpoint inhibitors

Although immune checkpoint inhibitors (ICIs) have greatly improved the prognosis of some cancer patients, the majority still fail to respond adequately, and the available biomarkers cannot reliably predict drug efficacy. The gut microbiota has received widespread attention among the various intrinsic and extrinsic factors contributing to drug resistance. As an essential regulator of physiological function, the impact of gut microbiota on host immunity and response to cancer therapy is increasingly recognized. Several studies have demonstrated significant differences in gut microbiota between responders and nonresponders. The gut microbiota associated with better clinical outcomes is called 'favorable gut microbiota'. Significantly, interventions can alter the gut microbiota. By shifting the gut microbiota to the 'favorable' one through various modifications, preclinical and clinical studies have yielded more pronounced responses and better clinical outcomes when combined with ICIs treatment, providing novel approaches to improve the efficacy of cancer immunotherapy. These findings may be attributed to the effects of gut microbiota and its metabolites on the immune microenvironment and the systemic immune system, but the underlying mechanisms remain to be discovered. In this review, we summarize the clinical evidence that the gut microbiota is strongly associated with the outcomes of ICI treatment and describe the gut microbiota characteristics associated with better clinical outcomes. We then expand on the current prevalent modalities of gut microbiota regulation, provide a comprehensive overview of preclinical and clinical research advances in improving the therapeutic efficacy and prognosis of ICIs by modulating gut microbiota, and suggest fundamental questions we need to address and potential directions for future research expansion.

Drug-microbiota interactions: an emerging priority for precision medicine

Individual variability in drug response (IVDR) can be a major cause of adverse drug reactions (ADRs) and prolonged therapy, resulting in a substantial health and economic burden. Despite extensive research in pharmacogenomics regarding the impact of individual genetic background on pharmacokinetics (PK) and pharmacodynamics (PD), genetic diversity explains only a limited proportion of IVDR. The role of gut microbiota, also known as the second genome, and its metabolites in modulating therapeutic outcomes in human diseases have been highlighted by recent studies. Consequently, the burgeoning field of pharmacomicrobiomics aims to explore the correlation between microbiota variation and IVDR or ADRs. This review presents an up-to-date overview of the intricate interactions between gut microbiota and classical therapeutic agents for human systemic diseases, including cancer, cardiovascular diseases (CVDs), endocrine diseases, and others. We summarise how microbiota, directly and indirectly, modify the absorption, distribution, metabolism, and excretion (ADME) of drugs. Conversely, drugs can also modulate the composition and function of gut microbiota, leading to changes in microbial metabolism and immune response. We also discuss the practical challenges, strategies, and opportunities in this field, emphasizing the critical need to develop an innovative approach to multi-omics, integrate various data types, including human and microbiota genomic data, as well as translate lab data into clinical practice. To sum up, pharmacomicrobiomics represents a promising avenue to address IVDR and improve patient outcomes, and further research in this field is imperative to unlock its full potential for precision medicine.

Gut Microbiome in Patients With Early-Stage and Late-Stage Melanoma

Importance

The gut microbiome modulates the immune system and responses to immunotherapy in patients with late-stage melanoma. It is unknown whether fecal microbiota profiles differ between healthy individuals and patients with melanoma or if microbiota profiles differ among patients with different stages of melanoma. Defining gut microbiota profiles in individuals without melanoma and those with early-stage and late-stage melanoma may reveal features associated with disease progression.

Objective

To characterize and compare gut microbiota profiles between healthy volunteers and patients with melanoma and between patients with early-stage and late-stage melanoma.

Design, Setting, and Participants

This single-site case-control study took place at an academic comprehensive cancer center. Fecal samples were collected from systemic treatment-naive patients with stage I to IV melanoma from June 1, 2015, to January 31, 2019, and from healthy volunteers from June 1, 2021, to January 31, 2022. Patients were followed up for disease recurrence until November 30, 2021.

Main Outcomes and Measures

Fecal microbiota was profiled by 16S ribosomal RNA sequencing. Clinical and pathologic characteristics, treatment, and disease recurrence were extracted from electronic medical records. Fecal microbiome diversity, taxonomic profiles and inferred functional profiles were compared between groups.

Results

A total of 228 participants were enrolled (126 men [55.3%]; median age, 59 [range, 21-90] years), including 49 volunteers without melanoma, 38 patients with early-stage melanoma (29 with stage I or melanoma in situ and 9 with stage II), and 141 with late-stage melanoma (66 with stage III and 75 with stage IV). Community differences were observed between patients with melanoma and volunteers. Patients with melanoma had a higher relative abundance of Fusobacterium compared with controls on univariate analysis (0.19% vs 0.003%; P < .001), but this association was attenuated when adjusted for covariates (log2 fold change of 5.18 vs controls; P = .09). Microbiomes were distinct between patients with early-stage and late-stage melanoma. Early-stage melanoma had a higher alpha diversity (Inverse Simpson Index 14.6 [IQR, 9.8-23.0] vs 10.8 [IQR, 7.2-16.8]; P = .003), and a higher abundance of the genus Roseburia on univariate analysis (2.4% vs 1.2%; P < .001) though statistical significance was lost with covariate adjustment (log2 fold change of 0.86 vs controls; P = .13). Multiple functional pathways were differentially enriched between groups. No associations were observed between the microbial taxa and disease recurrence in patients with stage III melanoma treated with adjuvant immunotherapy.

Conclusions and Relevance

The findings of this case-control study suggest that fecal microbiota profiles were significantly different among patients with melanoma and controls and between patients with early-stage and late-stage melanoma. Prospective investigations of the gut microbiome and changes that occur with disease progression may identify future microbial targets for intervention.

Towards modulating the gut microbiota to enhance the efficacy of immune-checkpoint inhibitors

The gut microbiota modulates immune processes both locally and systemically. This includes whether and how the immune system reacts to emerging tumours, whether antitumour immune responses are reactivated during treatment with immune-checkpoint inhibitors (ICIs), and whether unintended destructive immune pathologies accompany such treatment. Advances over the past decade have established that the gut microbiota is a promising target and that modulation of the microbiota might overcome resistance to ICIs and/or improve the safety of treatment. However, the specific mechanisms through which the microbiota modulates antitumour immunity remain unclear. Understanding the biology underpinning microbial associations with clinical outcomes in patients receiving ICIs, as well as the landscape of a 'healthy' microbiota would provide a critical foundation to facilitate opportunities to effectively manipulate the microbiota and thus improve patient outcomes. In this Review, we explore the role of diet and the gut microbiota in shaping immune responses during treatment with ICIs and highlight the key challenges in attempting to leverage the gut microbiome as a practical tool for the clinical management of patients with cancer.

Can physiologic colonic [18F]FDG uptake in PET/CT imaging predict response to immunotherapy in metastatic melanoma?

AIM

The development of biomarkers that can reliably and early predict response to immune checkpoint inhibitors (ICIs) is crucial in melanoma. In recent years, the gut microbiome has emerged as an important regulator of immunotherapy response, which may, moreover, serve as a surrogate marker and prognosticator in oncological patients under immunotherapy. Aim of the present study is to investigate if physiologic colonic [18F]FDG uptake in PET/CT before start of ICIs correlates with clinical outcome of metastatic melanoma patients. The relation between [18F]FDG uptake in lymphoid cell-rich organs and long-term patient outcome is also assessed.

METHODOLOGY

One hundred nineteen stage IV melanoma patients scheduled for immunotherapy with ipilimumab, applied either as monotherapy or in combination with nivolumab, underwent baseline [18F]FDG PET/CT. PET/CT data analysis consisted of standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) calculations in the colon as well as measurements of the colon-to-liver SUV ratios (CLRmean, CLRmax). Visual grading of colon uptake based on a four-point scale was also performed. Moreover, the spleen-to-liver SUV ratios (SLRmean, SLRmax) and the bone marrow-to-liver SUV ratios (BLRmean, BLRmax) were calculated. We also measured serum lipopolysaccharide (LPS) levels as a marker for bacterial translocation and surrogate for mucosal defense homeostasis. The results were correlated with patients' best clinical response, progression-free survival (PFS), and overall survival (OS) as well as clinical signs of colitis.

RESULTS

Median follow-up [95%CI] from the beginning of immunotherapy was 64.6 months [61.0-68.6 months]. Best response to treatment was progressive disease (PD) for 60 patients, stable disease (SD) for 37 patients, partial response (PR) for 18 patients, and complete response (CR) for 4 patients. Kaplan-Meier curves demonstrated a trend for longer PFS and OS in patients with lower colonic SUV and CLR values; however, no statistical significance for these parameters as prognostic factors was demonstrated. On the other hand, patients showing disease control as best response to treatment (SD, PR, CR) had significantly lower colonic MTV and TLG than those showing PD. With regard to lymphoid cell-rich organs, significantly lower baseline SLRmax and BLRmax were observed in patients responding with disease control than progression to treatment. Furthermore, patients with lower SLRmax and BLRmax values had a significantly longer OS when dichotomized at their median. In multivariate analysis, PET parameters that were found to significantly adversely correlate with patient survival were colonic MTV for PFS, colonic TLG for PFS, and BLRmax for PFS and OS.

CONCLUSIONS

Physiologic colonic [18F]FDG uptake in PET/CT, as assessed by means of SUV, before start of ipilimumab-based treatment does not seem to independently predict patient survival of metastatic melanoma. On the other hand, volumetric PET parameters, such as MTV and TLG, derived from the normal gut may identify patients showing disease control to immunotherapy and significantly correlate with PFS. Moreover, the investigation of glucose metabolism in the spleen and the bone marrow may offer prognostic information.

Non-pharmaceutical interventions to optimize cancer immunotherapy

The traditional picture of cancer patients as weak individuals requiring maximum rest and protection is beginning to dissolve. Too much focus on the medical side and one's own vulnerability and mortality might be counterproductive and not doing justice to the complexity of human nature. Unlike cytotoxic and lympho-depleting treatments, immune-engaging therapies strengthen the immune system and are typically less harmful for patients. Thus, cancer patients receiving checkpoint inhibitors are not viewed as being vulnerable per se, at least not in immunological and physical terms. This perspective article advocates a holistic approach to cancer immunotherapy, with an empowered patient in the center, focusing on personal resources and receiving domain-specific support from healthcare professionals. It summarizes recent evidence on non-pharmaceutical interventions to enhance the efficacy of immune checkpoint blockade and improve quality of life. These interventions target behavioral factors such as diet, physical activity, stress management, circadian timing of checkpoint inhibitor infusion, and waiving unnecessary co-medication curtailing immunotherapy efficacy. Non-pharmaceutical interventions are universally accessible, broadly applicable, instantly actionable, scalable, and economically sustainable, creating value for all stakeholders involved. Most importantly, this holistic framework re-emphasizes the patient as a whole and harnesses the full potential of anticancer immunity and checkpoint blockade, potentially leading to survival benefits. Digital therapeutics are proposed to accompany the patients on their mission toward change in lifestyle-related behaviors for creating optimal conditions for treatment efficacy and personal growth.

Learning from the microbes: exploiting the microbiome to enforce T cell immunotherapy

The opportunities genetic engineering has created in the field of adoptive cellular therapy for cancer are accelerating the development of novel treatment strategies using chimeric antigen receptor (CAR) and T cell receptor (TCR) T cells. The great success in the context of hematologic malignancies has made especially CAR T cell therapy a promising approach capable of achieving long-lasting remission. However, the causalities involved in mediating resistance to treatment or relapse are still barely investigated. Research on T cell exhaustion and dysfunction has drawn attention to host-derived factors that define both the immune and tumor microenvironment (TME) crucially influencing efficacy and toxicity of cellular immunotherapy. The microbiome, as one of the most complex host factors, has become a central topic of investigations due to its ability to impact on health and disease. Recent findings support the hypothesis that commensal bacteria and particularly microbiota-derived metabolites educate and modulate host immunity and TME, thereby contributing to the response to cancer immunotherapy. Hence, the composition of microbial strains as well as their soluble messengers are considered to have predictive value regarding CAR T cell efficacy and toxicity. The diversity of mechanisms underlying both beneficial and detrimental effects of microbiota comprise various epigenetic, metabolic and signaling-related pathways that have the potential to be exploited for the improvement of CAR T cell function. In this review, we will discuss the recent findings in the field of microbiome-cancer interaction, especially with respect to new trajectories that commensal factors can offer to advance cellular immunotherapy.

Biomarkers of immune checkpoint inhibitor response and toxicity: Challenges and opportunities

Immune checkpoint inhibitors have transformed cancer therapy, but their optimal use is still constrained by lack of response and toxicity. Biomarkers of response may facilitate drug development by allowing appropriate therapy selection and focusing clinical trial enrollment. However, aside from PD-L1 staining in a subset of tumors and rarely mismatch repair deficiency, no biomarkers are routinely used in the clinic. In addition, severe toxicities may cause severe morbidity, therapy discontinuation, and even death. Here, we review the state of the field with a focus on our research in therapeutic biomarkers and toxicities from immune checkpoint inhibitors.

Gut OncoMicrobiome Signatures (GOMS) as next-generation biomarkers for cancer immunotherapy

Oncogenesis is associated with intestinal dysbiosis, and stool shotgun metagenomic sequencing in individuals with this condition might constitute a non-invasive approach for the early diagnosis of several cancer types. The prognostic relevance of antibiotic intake and gut microbiota composition urged investigators to develop tools for the detection of intestinal dysbiosis to enable patient stratification and microbiota-centred clinical interventions. Moreover, since the advent of immune-checkpoint inhibitors (ICIs) in oncology, the identification of biomarkers for predicting their efficacy before starting treatment has been an unmet medical need. Many previous studies addressing this question, including a meta-analysis described herein, have led to the description of Gut OncoMicrobiome Signatures (GOMS). In this Review, we discuss how patients with cancer across various subtypes share several GOMS with individuals with seemingly unrelated chronic inflammatory disorders who, in turn, tend to have GOMS different from those of healthy individuals. We discuss findings from the aforementioned meta-analysis of GOMS patterns associated with clinical benefit from or resistance to ICIs across different cancer types (in 808 patients), with a focus on metabolic and immunological surrogate markers of intestinal dysbiosis, and propose practical guidelines to incorporate GOMS in decision-making for prospective clinical trials in immuno-oncology.

Gut microbiota interactions with antitumor immunity in colorectal cancer: From understanding to application

Colorectal cancer (CRC) is one of highly prevalent cancer. Immunotherapy with immune checkpoint inhibitors (ICIs) has dramatically changed the landscape of treatment for many advanced cancers, but CRC still exhibits suboptimal response to immunotherapy. The gut microbiota can affect both anti-tumor and pro-tumor immune responses, and further modulate the efficacy of cancer immunotherapy, particularly in the context of therapy with ICIs. Therefore, a deeper understanding of how the gut microbiota modulates immune responses is crucial to improve the outcomes of CRC patients receiving immunotherapy and to overcome resistance in nonresponders. The present review aims to describe the relationship between the gut microbiota, CRC, and antitumor immune responses, with a particular focus on key studies and recent findings on the effect of the gut microbiota on the antitumor immune activity. We also discuss the potential mechanisms by which the gut microbiota influences host antitumor immune responses as well as the prospective role of intestinal flora in CRC treatment. Furthermore, the therapeutic potential and limitations of different modulation strategies for the gut microbiota are also discussed. These insights may facilitate to better comprehend the interplay between the gut microbiota and the antitumor immune responses of CRC patients and provide new research pathways to enhance immunotherapy efficacy and expand the patient population that could be benefited by immunotherapy.

TIME for Bugs: The Immune Microenvironment and Microbes in Precancer

Major advances in our understanding of the tumor immune microenvironment (TIME) in established cancer have been made, including the influence of host-intrinsic (host genomics) and -extrinsic factors (such as diet and the microbiome) on treatment response. Nonetheless, the immune and microbiome milieu across the spectrum of precancerous tissue and early neoplasia is a growing area of interest. There are emerging data describing the contribution of the immune microenvironment and microbiota on benign and premalignant tissues, with opportunities to target these factors in cancer prevention and interception. Throughout this review, we provide rationale for not only the critical need to further elucidate the premalignant immune microenvironment, but also for the utility of pharmacologic and lifestyle interventions to alter the immune microenvironment of early lesions to reverse carcinogenesis. Novel research methodologies, such as implementing spatial transcriptomics and proteomics, in combination with innovative sampling methods will advance precision targeting of the premalignant immune microenvironment. Additional studies defining the continuum of immune and microbiome evolution, which emerges in parallel with tumor development, will provide novel opportunities for cancer interception at the earliest steps in carcinogenesis.

The Microbiome in Advanced Melanoma: Where Are We Now?

PURPOSE OF REVIEW

This review summarizes recent data linking gut microbiota composition to ICI outcomes and gut microbiota-specific interventional clinical trials in melanoma.

RECENT FINDINGS

Preclinical and clinical studies have demonstrated the effects of the gut microbiome modulation upon ICI response in advanced melanoma, with growing evidence supporting the ability of the gut microbiome to restore or improve ICI response in advanced melanoma through dietary fiber, probiotics, and FMT. Immune checkpoint inhibitors (ICI) targeting the PD-1, CTLA-4, and LAG-3 negative regulatory checkpoints have transformed the management of melanoma. ICIs are FDA-approved in advanced metastatic disease, stage III resected melanoma, and high-risk stage II melanoma and are being investigated more recently in the management of high-risk resectable melanoma in the peri-operative setting. The gut microbiome has emerged as an important tumor-extrinsic modulator of both response and immune-related adverse event (irAE) development in ICI-treated cancer in general, and melanoma in particular.

The Role of Artificial Intelligence in Deciphering Diet-Disease Relationships: Case Studies

Modernization of society from a rural, hunter-gatherer setting into an urban and industrial habitat, with the associated dietary changes, has led to an increased prevalence of cardiometabolic and additional noncommunicable diseases, such as cancer, inflammatory bowel disease, and neurodegenerative and autoimmune disorders. However, while dietary sciences have been rapidly evolving to meet these challenges, validation and translation of experimental results into clinical practice remain limited for multiple reasons, including inherent ethnic, gender, and cultural interindividual variability, among other methodological, dietary reporting-related, and analytical issues. Recently, large clinical cohorts with artificial intelligence analytics have introduced new precision and personalized nutrition concepts that enable one to successfully bridge these gaps in a real-life setting. In this review, we highlight selected examples of case studies at the intersection between diet-disease research and artificial intelligence. We discuss their potential and challenges and offer an outlook toward the transformation of dietary sciences into individualized clinical translation.

Fecal microbiota transplantation plus anti-PD-1 immunotherapy in advanced melanoma: a phase I trial

Fecal microbiota transplantation (FMT) represents a potential strategy to overcome resistance to immune checkpoint inhibitors in patients with refractory melanoma; however, the role of FMT in first-line treatment settings has not been evaluated. We conducted a multicenter phase I trial combining healthy donor FMT with the PD-1 inhibitors nivolumab or pembrolizumab in 20 previously untreated patients with advanced melanoma. The primary end point was safety. No grade 3 adverse events were reported from FMT alone. Five patients (25%) experienced grade 3 immune-related adverse events from combination therapy. Key secondary end points were objective response rate, changes in gut microbiome composition and systemic immune and metabolomics analyses. The objective response rate was 65% (13 of 20), including four (20%) complete responses. Longitudinal microbiome profiling revealed that all patients engrafted strains from their respective donors; however, the acquired similarity between donor and patient microbiomes only increased over time in responders. Responders experienced an enrichment of immunogenic and a loss of deleterious bacteria following FMT. Avatar mouse models confirmed the role of healthy donor feces in increasing anti-PD-1 efficacy. Our results show that FMT from healthy donors is safe in the first-line setting and warrants further investigation in combination with immune checkpoint inhibitors. ClinicalTrials.gov identifier NCT03772899 .

Corticosteroids and Cancer Immunotherapy

Despite revolutionizing cancer management, immunotherapies dysregulate the immune system, leading to immune-mediated adverse events. These common and potentially dangerous toxicities are often treated with corticosteroids, which are among the most prescribed drugs in oncology for a wide range of cancer and noncancer indications. While steroids exert several mechanisms to reduce immune activity, immunotherapies, such as immune checkpoint inhibitors (ICI), are designed to enhance the immune system's inherent antitumor activity. Because ICI requires an intact and robust immune response, the immunosuppressive properties of steroids have led to a widespread concern that they may interfere with antitumor responses. However, the existing data of the effect of systemic steroids on immunotherapy efficacy remain somewhat conflicted and unclear. To inform clinical decision-making and improve outcomes, we review the impact of steroids on antitumor immunity, recent advances in the knowledge of their impact on ICI efficacy in unique populations and settings, associated precautions, and steroid-sparing treatment approaches.

Immune Checkpoint Inhibitors and the Exposome: Host-Extrinsic Factors Determine Response, Survival, and Toxicity

Cancer immunotherapy, largely represented by immune checkpoint inhibitors (ICI), has led to substantial changes in preclinical cancer research and clinical oncology practice over the past decade. However, the efficacy and toxicity profiles of ICIs remain highly variable among patients, with only a fraction achieving a significant benefit. New combination therapeutic strategies are being investigated, and the search for novel predictive biomarkers is ongoing, mainly focusing on tumor- and host-intrinsic components. Less attention has been directed to all the external, potentially modifiable factors that compose the exposome, including diet and lifestyle, infections, vaccinations, and concomitant medications, that could affect the immune system response and its activity against cancer cells. We hereby provide a review of the available clinical evidence elucidating the impact of host-extrinsic factors on ICI response and toxicity.

Cutaneous immune-related adverse events to immune checkpoint inhibitors: from underlying immunological mechanisms to multi-omics prediction

The development of immune checkpoint inhibitors (ICIs) has dramatically altered the landscape of therapy for multiple malignancies, including urothelial carcinoma, non-small cell lung cancer, melanoma and gastric cancer. As part of their anti-tumor properties, ICIs can enhance susceptibility to inflammatory side effects known as immune-related adverse events (irAEs), in which the skin is one of the most commonly and rapidly affected organs. Although numerous questions still remain unanswered, multi-omics technologies have shed light into immunological mechanisms, as well as the correlation between ICI-induced activation of immune systems and the incidence of cirAE (cutaneous irAEs). Therefore, we reviewed integrated biological layers of omics studies combined with clinical data for the prediction biomarkers of cirAEs based on skin pathogenesis. Here, we provide an overview of a spectrum of dermatological irAEs, discuss the pathogenesis of this "off-tumor toxicity" during ICI treatment, and summarize recently investigated biomarkers that may have predictive value for cirAEs via multi-omics approach. Finally, we demonstrate the prognostic significance of cirAEs for immune checkpoint blockades.

Potential role of gut microbes in the efficacy and toxicity of immune checkpoints inhibitors

In recent years, Immune checkpoint inhibitors have been extensively used in the treatment of a variety of cancers. However, the response rates ranging from 13% to 69% depending on the tumor type and the emergence of immune-related adverse events have posed significant challenges for clinical treatment. As a key environmental factor, gut microbes have a variety of important physiological functions such as regulating intestinal nutrient metabolism, promoting intestinal mucosal renewal, and maintaining intestinal mucosal immune activity. A growing number of studies have revealed that gut microbes further influence the anticancer effects of tumor patients through modulation of the efficacy and toxicity of immune checkpoint inhibitors. Currently, faecal microbiota transplantation (FMT) have been developed relatively mature and suggested as an important regulator in order to enhance the efficacy of treatment. This review is dedicated to exploring the impact of differences in flora composition on the efficacy and toxicity of immune checkpoint inhibitors as well as to summarizing the current progress of FMT.

An updated review of gastrointestinal toxicity induced by PD-1 inhibitors: from mechanisms to management

PD-1 inhibitors, as one of commonly used immune checkpoint inhibitors, enable T-cell activation and prevent immune escape by blocking the PD-1/PD-L1 signaling pathway. They have transformed the treatment landscape for cancer in recent years, due to the advantages of significantly prolonging patients' survival and improving their life quality. However, the ensuing unpredictable immune-related adverse effects (irAEs) plague clinicians, such as colitis and even potentially fatal events like intestinal perforation and obstruction. Therefore, understanding the clinical manifestations and grading criteria, underlying mechanisms, available diverse therapies, accessible biomarkers, and basis for risk stratification is of great importance for the management. Current evidence suggests that irAEs may be a marker of clinical benefit to immunotherapy in patients, so whether to discontinue PD-1 inhibitors after the onset of irAEs and rechallenge after remission of irAEs requires further evaluation of potential risk-reward ratios as well as more data from large-scale prospective studies to fully validate. At the end, the rare gastrointestinal toxicity events caused by PD-1 inhibitors are also sorted out. This review provides a summary of available data on the gastrointestinal toxicity profile caused by PD-1 inhibitors, with the aim of raising clinicians' awareness in daily practice, so that patients can safely benefit from therapy.

Comparative Analysis of Fecal Microbiota in Vegetarians and Omnivores

Diet has a significant impact on fecal microbiota, which in turn plays an important role in human health. To evaluate the impact of dietary habits on fecal microbiota, we investigated the fecal microbial composition in vegetarians and omnivores using 16S rRNA gene sequencing, and estimated the correlation between fecal microbiota, body mass and diet. The dietary data showed that vegetarians consumed more plant-based foods rich in dietary fiber, omnivores consumed more animal-based foods rich in fat and overweight and obese people consumed more high-energy foods. Compared to omnivores, vegetarians had greater richness and diversity in their fecal microbiota. The Firmicutes/Bacteroidetes ratio was lower and the Prevotella/Bacteroides ratio was higher in vegetarians. The meat intake correlated positively with the proportion of Bacteroides and negatively with the proportion of Prevotella. The composition and diversity in fecal microbiota in the normal weight group, overweight group and obesity group were similar to that of vegetarians and omnivores, respectively. This paper revealed the distinctive characteristics of fecal microbiota in vegetarians and omnivores. The omnivorous diet contained more fat, which reduced the fecal microbial diversity, and was more likely to lead to being overweight or obese.

Gut microbiota in colorectal cancer development and therapy

Colorectal cancer (CRC) is one of the commonest cancers globally. A unique aspect of CRC is its intimate association with the gut microbiota, which forms an essential part of the tumour microenvironment. Research over the past decade has established that dysbiosis of gut bacteria, fungi, viruses and Archaea accompanies colorectal tumorigenesis, and these changes might be causative. Data from mechanistic studies demonstrate the ability of the gut microbiota to interact with the colonic epithelia and immune cells of the host via the release of a diverse range of metabolites, proteins and macromolecules that regulate CRC development. Preclinical and some clinical evidence also underscores the role of the gut microbiota in modifying the therapeutic responses of patients with CRC to chemotherapy and immunotherapy. Herein, we summarize our current understanding of the role of gut microbiota in CRC and outline the potential translational and clinical implications for CRC diagnosis, prevention and treatment. Emphasis is placed on how the gut microbiota could now be better harnessed by developing targeted microbial therapeutics as chemopreventive agents against colorectal tumorigenesis, as adjuvants for chemotherapy and immunotherapy to boost drug efficacy and safety, and as non-invasive biomarkers for CRC screening and patient stratification. Finally, we highlight the hurdles and potential solutions to translating our knowledge of the gut microbiota into clinical practice.

A review of the impact of energy balance on triple-negative breast cancer

Cancer cells cannot proliferate without sufficient energy to generate biomass for rapid cell division, as well as to fuel their functions at baseline. For this reason, many recent observational and interventional studies have focused on increasing energy expenditure and/or reducing energy intake during and after cancer treatment. The impact of variance in diet composition and in exercise on cancer outcomes has been detailed extensively elsewhere and is not the primary focus of this review. Instead, in this translational, narrative review we examine studies of how energy balance impacts anticancer immune activation and outcomes in triple-negative breast cancer (TNBC). We discuss preclinical, clinical observational, and the few clinical interventional studies on energy balance in TNBC. We advocate for the implementation of clinical studies to examine how optimizing energy balance-through changes in diet and/or exercise-may optimize the response to immunotherapy in people with TNBC. It is our conviction that by taking a holistic approach that includes energy balance as a key factor to be considered during and after treatment, cancer care may be optimized, and the detrimental effects of cancer treatment and recovery on overall health may be minimized.

An integrated tumor, immune and microbiome atlas of colon cancer

The lack of multi-omics cancer datasets with extensive follow-up information hinders the identification of accurate biomarkers of clinical outcome. In this cohort study, we performed comprehensive genomic analyses on fresh-frozen samples from 348 patients affected by primary colon cancer, encompassing RNA, whole-exome, deep T cell receptor and 16S bacterial rRNA gene sequencing on tumor and matched healthy colon tissue, complemented with tumor whole-genome sequencing for further microbiome characterization. A type 1 helper T cell, cytotoxic, gene expression signature, called Immunologic Constant of Rejection, captured the presence of clonally expanded, tumor-enriched T cell clones and outperformed conventional prognostic molecular biomarkers, such as the consensus molecular subtype and the microsatellite instability classifications. Quantification of genetic immunoediting, defined as a lower number of neoantigens than expected, further refined its prognostic value. We identified a microbiome signature, driven by Ruminococcus bromii, associated with a favorable outcome. By combining microbiome signature and Immunologic Constant of Rejection, we developed and validated a composite score (mICRoScore), which identifies a group of patients with excellent survival probability. The publicly available multi-omics dataset provides a resource for better understanding colon cancer biology that could facilitate the discovery of personalized therapeutic approaches.

Neoadjuvant Checkpoint Immunotherapy and Melanoma: The Time Is Now

The role of neoadjuvant therapy is undergoing an historic shift in oncology. The emergence of potent immunostimulatory anticancer agents has transformed neoadjuvant therapy from a useful tool in minimizing surgical morbidity to a life-saving treatment with curative promise, led by research in the field of melanoma. Health practitioners have witnessed remarkable improvements in melanoma survival outcomes over the past decade, beginning with checkpoint immunotherapies and BRAF-targeted therapies in the advanced setting that were successfully adopted into the postsurgical adjuvant setting for high-risk resectable disease. Despite substantial reductions in postsurgical recurrence, high-risk resectable melanoma has remained a life-altering and potentially fatal disease. In recent years, data from preclinical models and early-phase clinical trials have pointed to the potential for greater clinical efficacy when checkpoint inhibitors are administered in the neoadjuvant rather than adjuvant setting. Early feasibility studies showed impressive pathologic response rates to neoadjuvant immunotherapy, which were associated with recurrence-free survival rates of over 90%. Recently, the randomized phase II SWOG S1801 trial (ClinicalTrials.gov identifier: NCT03698019) reported a 42% reduction in 2-year event-free survival risk with neoadjuvant versus adjuvant pembrolizumab in resectable stage IIIB-D/IV melanoma (72% v 49%; hazard ratio, 0.58; P = .004), establishing neoadjuvant single-agent immunotherapy as a new standard of care. A randomized phase III trial of neoadjuvant immunotherapy in resectable stage IIIB-D melanoma, NADINA (ClinicalTrials.gov identifier: NCT04949113), is ongoing, as are feasibility studies in high-risk stage II disease. With a swathe of clinical, quality-of-life, and economic benefits, neoadjuvant immunotherapy has the potential to redefine the contemporary management of resectable tumors.

Leveraging the microbiome in the treatment of sepsis: potential pitfalls and new perspectives

PURPOSE OF REVIEW

This review aims to provide an overview of the current knowledge about microbiota-targeted therapies in sepsis, and calls out - despite recent negative studies - not to halt our efforts of translating these tools into regular medical practice.

RECENT FINDINGS

The intestinal microbiome has an important role in shaping our immune system, and microbiota-derived metabolites prime innate and adaptive inflammatory responses to infectious pathogens. Microbiota composition is severely disrupted during sepsis, which has been linked to increased risk of mortality and secondary infections. However, efforts of using these microbes as a tool for prognostic or therapeutic purposes have been unsuccessful so far, and recent trials studying the impact of probiotics in critical illness did not improve patient outcomes. Despite these negative results, researchers must continue their attempts of harnessing the microbiome to improve sepsis survival in patients with a high risk of clinical deterioration. Promising research avenues that could potentially benefit sepsis patients include the development of next-generation probiotics, use of the microbiome as a theranostic tool to direct therapy, and addressing the restoration of microbial communities following ICU discharge.

SUMMARY

Although research focused on microbiome-mediated therapy in critically ill patients has not yielded the results that were anticipated, we should not abandon our efforts to translate promising preclinical findings into clinical practice.

The Microbiome and Liver Cancer

ABSTRACT

The gut microbiome and liver are anatomically and functionally connected. The impact of the gut microbiota or microbial metabolites on liver cancer progression via immune cells has been recently revealed across various preclinical models. Commensal gut microbes of liver cancer patients differ from control subjects, and their composition is affected by the etiology of the hepatocellular carcinoma. The gut microbiota represents a potential novel target for intervention as shown in patients with melanoma, but we still lack data in patients with hepatocellular carcinoma. Fecal microbiota transplantation and dietary approaches may improve immunotherapy efficacy, and a couple of clinical trials are ongoing. In liver cancer, the ongoing recognition of interactions between gut microbes and the tumor immune microenvironment provides an exciting therapeutic avenue to complement established immunotherapy.

Fecal Microbiota Transplantation as a Cancer Therapeutic

ABSTRACT

For decades, cancer research and treatment focused on the cellular level, viewing cancer as a genetic disease of cell transformation. In the era of chemotherapy and radiotherapy, studies from the second half of the 19th century suggesting an association between the microbiota and cancer were almost neglected. The main focus of the field was limited to identification of specific viruses and bacteria that may serve as direct carcinogens leading to the recognition of 7 viruses (i.e., human papillomavirus, hepatitis B virus, and Kaposi sarcoma-associated herpesvirus) and 1 bacterium (Helicobacter pylori) as human carcinogens by the International Agency for Research on Cancer (https://monographs.iarc.who.int/agents-classified-by-the-iarc/). Shortly after the publication of the first draft of the human genome project in February 2001, the Nobel laureate microbiologist Joshua Lederberg raised the question: "Is human identity all in the genes?" It took more than a decade later and the development of multiomic techniques to confirm that his answer "each one of us is a small ecological community" was correct (Lederberg J. Keynote Address: Beyond the Genome. Brooklyn Law Rev 67). This ecological notion became relevant to cancer prevention, prediction, and treatment following the immunotherapy revolution and the understanding of the metabolic and immunologic roles of the microbiota in health and disease. Recently, the microbiota was recognized as an emerging hallmark of cancer following a large body of research showing its role in tumorigenesis, treatment efficacy and toxicity, and initial data regarding the role of microbial modulation in cancer therapy (Cancer Discov 2022;12(1):31-46). In the current review, we will focus on the role of fecal microbiota transplantation, the first microbial modulation technique that is used mainly in low-complexity conditions such as recurrent Clostridium difficile infections (Aliment Pharmacol Ther 2017;46(5):479-493), as a possible cancer therapeutic. However, to better understand the suggested roles of fecal microbiota transplantation in medical oncology, we first need to understand cancer as an ecological niche and the role of the microbiota in tumorigenesis and cancer treatment, specifically immunotherapy.

Association of a Mediterranean Diet With Outcomes for Patients Treated With Immune Checkpoint Blockade for Advanced Melanoma

Importance

Immune checkpoint blockade (ICB) has improved the survival of patients with advanced melanoma. Durable responses are observed for 40% to 60% of patients, depending on treatment regimens. However, there is still large variability in the response to treatment with ICB, and patients experience a range of immune-related adverse events of differing severity. Nutrition, through its association with the immune system and gut microbiome, is a poorly explored but appealing target with potential to improve the efficacy and tolerability of ICB.

Objective

To investigate the association between habitual diet and response to treatment with ICB.

Design, Setting, and Participants

This multicenter cohort study (the PRIMM study) was conducted in cancer centers in the Netherlands and UK and included 91 ICB-naive patients with advanced melanoma who were receiving ICB between 2018 and 2021.

Exposures

Patients were treated with anti-programmed cell death 1 and anti-cytotoxic T lymphocyte-associated antigen 4 monotherapy or combination therapy. Dietary intake was assessed through food frequency questionnaires before treatment.

Main Outcomes and Measures

Clinical end points were defined as overall response rate (ORR), progression-free survival at 12 months (PFS-12), and immune-related adverse events that were grade 2 or higher.

Results

There were a total of 44 Dutch participants (mean [SD] age, 59.43 [12.74] years; 22 women [50%]) and 47 British participants (mean [SD] age, 66.21 [16.63] years; 15 women [32%]). Dietary and clinical data were prospectively collected from 91 patients receiving ICB between 2018 and 2021 for advanced melanoma in the UK and the Netherlands. Logistic generalized additive models revealed positive linear associations between a Mediterranean dietary pattern that was high in whole grains, fish, nuts, fruit, and vegetables and the probability of ORR and PFS-12 (probability of 0.77 for ORR; P = .02; false discovery rate, 0.032; effective degrees of freedom, 0.83; probability of 0.74 for PFS-12; P = .01; false discovery rate, 0.021; effective degrees of freedom, 1.54).

Conclusions and Relevance

This cohort study found a positive association between a Mediterranean diet, a widely recommended model of healthy eating, and response to treatment with ICB. Large prospective studies from different geographies are needed to confirm the findings and further elucidate the role of diet in the context of ICB.

The Gut Microbiome and Metastatic Renal Cell Carcinoma

The introduction of targeted therapy (TT) and immuno-oncology (IO) agents have revolutionized the treatment of metastatic renal cell carcinoma (mRCC). However, despite the significant improvements in survival and clinical response yielded by these agents, a significant percentage of patients still experience progressive disease. Evidence now suggests that microorganisms living in the gut (i.e., the gut microbiome) could be used as a biomarker for response and may also have utility in increasing response to these treatments. In this review, we present an overview of the role of the gut microbiome in cancer and its potential implications in the treatment of mRCC.

The Geriatric Nutritional Risk Index (GNRI) as a Prognostic Biomarker for Immune Checkpoint Inhibitor Response in Recurrent and/or Metastatic Head and Neck Cancer

Malnutrition is a frequent comorbidity in head and neck cancer patients and has been shown to impair immunotherapy response in other cancer types. The geriatric nutritional risk index (GNRI) assesses malnutrition using the patient's ideal weight, actual weight, and serum albumin. The aim of this study was to evaluate the prognostic relevance of malnutrition as determined by the GNRI for the response to immunotherapy in recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC). A total of 162 patients with R/M HNSCC who received immune checkpoint inhibitors were included. The associations between the GNRI and progression-free survival (PFS), overall survival (OS), and the disease control rate (DCR) were computed. Univariable analysis showed worse PFS for GNRI ≤ 98 (p < 0.001), ECOG performance status (PS) ≥ 2 (p = 0.012), and enteral (p = 0.009) and parenteral (p = 0.015) nutritional supplementation, and worse OS for GNRI < 92 (p < 0.001), ECOG PS ≥ 2 (p < 0.001), and enteral (p = 0.008) and parenteral (p = 0.023) nutritional supplementation. In our multivariable model, GNRI ≤ 98 (p = 0.012) and ECOG PS ≥ 2 (p = 0.025) were independent prognostic factors for PFS. For OS, GNRI < 92 (p < 0.001) and ECOG PS ≥ 2 (p < 0.001) were independent prognostic factors. A GNRI ≤ 98 was significantly associated with a lower DCR compared to a GNRI > 98 (p = 0.001). In conclusion, our findings suggest that the GNRI may be an effective predictor for response to immunotherapy in R/M HNSCC.

Dietary fiber and SCFAs in the regulation of mucosal immunity

Gut bacterial metabolites such as short-chain fatty acids (SCFAs) have important effects on immune cells and the gut. SCFAs derive from the fermentation of dietary fiber by gut commensal bacteria. Insufficient fiber intake thus compromises SCFA production and, as a consequence, the host's physiology (particularly immune functions). We propose that many Western diseases, including those associated with impaired mucosal responses such as food allergy and asthma, may be affected by insufficient fiber intake and reduced SCFA levels in the gut and blood. Insufficient fiber intake is 1 alternative, or contributor, on top of the "hygiene hypothesis" to the rise of Western lifestyle diseases, and the 2 ideas need to be reconciled. The mechanisms by which SCFAs influence immunity and gut homeostasis are varied; they include stimulation of G protein-coupled receptors (GPCRs), such as GPR43 or GPR41; inhibition of histone deacetylases (and hence, gene transcription changes); and induction of intracellular metabolic changes. SCFAs modulate at many different levels to alter mucosal homeostasis, including changes to gut epithelial integrity, increases in regulatory T-cell numbers and function, and decreased expression of numerous inflammatory cytokines. There is scope for preventing and/or treating diseases by using diets that alter SCFA levels.

Implication of the Gut Microbiome and Microbial-Derived Metabolites in Immune-Related Adverse Events: Emergence of Novel Biomarkers for Cancer Immunotherapy

Immune checkpoint inhibitors (ICIs) have changed how we think about tumor management. Combinations of anti-programmed death ligand-1 (PD-L1) immunotherapy have become the standard of care in many advanced-stage cancers, including as a first-line therapy. Aside from improved anti-tumor immunity, the mechanism of action of immune checkpoint inhibitors (ICIs) exposes a new toxicity profile known as immune-related adverse effects (irAEs). This novel toxicity can damage any organ, but the skin, digestive and endocrine systems are the most frequently afflicted. Most ICI-attributed toxicity symptoms are mild, but some are severe and necessitate multidisciplinary side effect management. Obtaining knowledge on the various forms of immune-related toxicities and swiftly changing treatment techniques to lower the probability of experiencing severe irAEs has become a priority in oncological care. In recent years, there has been a growing understanding of an intriguing link between the gut microbiome and ICI outcomes. Multiple studies have demonstrated a connection between microbial metagenomic and metatranscriptomic patterns and ICI efficacy in malignant melanoma, lung and colorectal cancer. The immunomodulatory effect of the gut microbiome can have a real effect on the biological background of irAEs as well. Furthermore, specific microbial signatures and metabolites might be associated with the onset and severity of toxicity symptoms. By identifying these biological factors, novel biomarkers can be used in clinical practice to predict and manage potential irAEs. This comprehensive review aims to summarize the clinical aspects and biological background of ICI-related irAEs and their potential association with the gut microbiome and metabolome. We aim to explore the current state of knowledge on the most important and reliable irAE-related biomarkers of microbial origin and discuss the intriguing connection between ICI efficacy and toxicity.

Monitoring and Modulating Diet and Gut Microbes to Enhance Response and Reduce Toxicity to Cancer Treatment

The gut microbiome comprises a diverse array of microbial species that have been shown to dynamically modulate host immunity both locally and systemically, as well as contribute to tumorigenesis. In this review, we discuss the scientific evidence on the role that gut microbes and diet play in response and toxicity to cancer treatment. We highlight studies across multiple cancer cohorts that have shown an association between particular gut microbiome signatures and an improved response to immune checkpoint blockade, chemotherapy, and adoptive cell therapies, as well as the role of particular microbes in driving treatment-related toxicity and how the microbiome can be modulated through strategies, such as fecal transplant. We also summarize the current literature that implicate high fiber and ketogenic diets in improved response rates to immunotherapy and chemotherapy, respectively. Finally, we discuss the relevance of these findings in the context of patient care, advocate for a holistic approach to cancer treatment, and comment on the next frontier of targeted gut and tumor microbiome modulation through novel therapeutics, dietary intervention, and precision-medicine approaches.

Microbiome influencers of checkpoint blockade-associated toxicity

Immunotherapy has greatly improved cancer outcomes, yet variability in response and off-target tissue damage can occur with these treatments, including immune checkpoint inhibitors (ICIs). Multiple lines of evidence indicate the host microbiome influences ICI response and risk of immune-related adverse events (irAEs). As the microbiome is modifiable, these advances indicate the potential to manipulate microbiome components to increase ICI success. We discuss microbiome features associated with ICI response, with focus on bacterial taxa and potential immune mechanisms involved in irAEs, and the overall goal of driving novel approaches to manipulate the microbiome to improve ICI efficacy while avoiding irAE risk.

Bodywide ecological interventions on cancer

Historically, cancer research and therapy have focused on malignant cells and their tumor microenvironment. However, the vascular, lymphatic and nervous systems establish long-range communication between the tumor and the host. This communication is mediated by metabolites generated by the host or the gut microbiota, as well by systemic neuroendocrine, pro-inflammatory and immune circuitries-all of which dictate the trajectory of malignant disease through molecularly defined biological mechanisms. Moreover, aging, co-morbidities and co-medications have a major impact on the development, progression and therapeutic response of patients with cancer. In this Perspective, we advocate for a whole-body 'ecological' exploration of malignant disease. We surmise that accumulating knowledge on the intricate relationship between the host and the tumor will shape rational strategies for systemic, bodywide interventions that will eventually improve tumor control, as well as quality of life, in patients with cancer.

Cross communication of diet-microbiome-immune interactions in cancer immunotherapy

Simpson et al. have highlighted a diet-driven microbiome community, which paves the way for landmark therapeutic avenues for facilitating efficacy and minimizing immune-related adverse events during neoadjuvant immune checkpoint inhibitor treatment in melanoma patients. This innovative attempt inspires application of the diet-microbiome-immune interaction axis to maximize clinical benefits.