Dietary Fiber and Melanoma: Exploring Microbiome-Driven Immune Modulation

Area of Science:

• Oncology
• Immunology
• Microbiome Research

Background:

• The gut microbiome significantly impacts melanoma development and response to immune checkpoint inhibitors (ICIs).
• Dietary fiber is a crucial modifiable factor influencing gut microbial composition and metabolite production.
• Understanding fiber's role is key to optimizing melanoma treatment outcomes.

Purpose of the Study:

• To review mechanistic, preclinical, and clinical evidence on how dietary fiber affects melanoma immunity and treatment.
• To explore the impact of fiber-rich diets and specific gut bacteria on melanoma immunotherapy.
• To identify potential fiber-based interventions for melanoma patients.

Main Methods:

• A comprehensive literature search was conducted across MEDLINE, Embase, and Scopus for studies within the last five years.
• 491 unique records were screened, and 49 relevant peer-reviewed studies were qualitatively synthesized.
• The review included mechanistic, preclinical, observational, and interventional research.

Main Results:

• Fiber fermentation yields short-chain fatty acids that regulate immune cell function and cytokine signaling.
• Preclinical models show fiber enhances anti-tumor immunity and ICI efficacy in a microbiota-dependent way.
• In humans, fiber intake and specific bacteria (e.g., Bifidobacterium, Faecalibacterium, Akkermansia) correlate with better ICI response, longer survival, and reduced colitis.

Conclusions:

• Dietary fiber shows promise as a safe adjunct therapy for melanoma immunotherapy.
• Further controlled trials are necessary to establish causality and optimize fiber interventions due to study variability and conflicting data.