Role of the Microbiome in Immunotherapy of Melanoma

Abstract

Novel immunotherapeutics for advanced melanoma have drastically changed survival rates and management strategies in recent years. Immune checkpoint inhibitors have emerged as efficacious agents for some patients but have not been proven to be as beneficial in other patient cohorts. Recent investigation into this observation has implicated the gut microbiome as a potential immunomodulator in regulating patient response to therapy. Numerous studies have provided evidence for this link. Bacterial colonization patterns have been associated with therapeutic outcomes, under the notion that favorable commensal organisms improve host immune response. This review aims to report the most recent and pertinent findings related to the relationship between gut microbial communities and melanoma therapy efficacy. This article also highlights the emerging frontier of artificial intelligence in its application regarding patient microbial composition evaluation, predictive models for therapy response, and recommendations for the future of probiotics and dietary interventions to optimize melanoma survival and outcomes.

The Gut Microbiome in Melanoma: A Piece of a Complex Puzzle

“…Immune checkpoint inhibitors have revolutionized treatment of late-stage melanoma, but it is still unclear why there is a variable response among patients. Increasing evidence substantiates the gut microbiome as a key contributor to a patient’s successful response . When stratifying patients with melanoma taking immune checkpoint inhibitors by treatment response, many studies identify key bacterial taxa associated with successful response, but no specific bacterial taxa or diversity is consistently associated with response across all studies.…”

“…Increasing evidence substantiates the gut microbiome as a key contributor to a patient's successful response. 12 When stratifying patients with melanoma taking immune checkpoint inhibitors by treatment response, many studies identify key bacterial taxa associated with successful response, but no specific bacterial taxa or diversity is consistently associated with response across all studies. Witt et al 4 evaluated baseline (treatment-naive) microbiome features in patients with stage III disease who had subsequent adjuvant treatment and monitored for disease recurrence, but also found no significant bacterial taxa associated with recurrence.…”