DIFFERENCES in gut microbiome between patients with early- or late-stage melanoma compared with controls were identified in a new single-site, case-controlled study. “The gut microbiome represents the largest collection of microbial communities within the human body and has become increasingly recognised for its potential effect on clinical cancer outcomes,” wrote Russel G. Witt, The University of Texas MD Anderson Cancer Center, Houston, USA, and colleagues.
Preclinical models and patient cohorts with metastatic melanoma have previously shown an association between the presence of some microbes in the gut and patient response to immunotherapy; however, data on microbiome composition in patients with melanoma is limited.
The team profiled faecal samples from 228 patients, including 38 with early-stage melanoma, 141 with late-stage melanoma, and 49 control subjects without melanoma, using 16S ribosomal RNA gene sequencing. Patients with melanoma had a higher relative abundance of Fusobacterium, compared with controls (0.190% versus 0.003%; p<0.001), but this association was lessened when adjusted for covariates (p=0.090). The authors noted that “Fusobacterium has been previously implicated in colorectal cancer, upper aerodigestive squamous cell carcinoma, and breast cancer tumorigenesis and progression by activating the Wnt pathway and inhibiting antitumoral immune responses.” Researchers further noted higher abundance of Roseburia and higher alpha diversity in those with early-stage melanoma, compared with patients with late-stage disease.
The study suggests that there is a link between melanomagenesis and diseases; however, more research is needed to whether development and progression could be influenced by modifying the gut microbiome.
