WEDNESDAY, Sept. 6, 2023 -- The fecal microbiota profile differs significantly between patients with melanoma and healthy controls, and for those in early- and late-stage melanoma, according to a study published online Aug. 30 in JAMA Dermatology.

Russell G. Witt, M.D., from the University of Texas MD Anderson Cancer Center in Houston, and colleagues characterized and compared gut microbiota profiles between healthy volunteers and patients with melanoma and between those with early- and late-stage melanoma in a single-site case-control study. Fecal samples were collected from systemic treatment-naive patients with stage I to IV melanoma and from healthy volunteers (38 patients with early-stage melanoma [29 with stage I or melanoma in situ and nine with stage II], 141 with late-stage melanoma [66 with stage III and 75 with stage IV], and 49 volunteers without melanoma). There were community differences observed between patients with melanoma and the volunteers.

The researchers found that in a univariate analysis, patients with melanoma had a higher relative abundance of Fusobacterium (0.19 versus 0.003 percent; P < 0.001), but after adjustment for covariates, the association was attenuated (P = 0.09). Patients with early- and late-stage melanoma had distinct microbiomes. Higher alpha diversity was seen in patients with early-stage melanoma (Inverse Simpson Index, 14.6 versus 10.8), and they had a higher abundance of the genus Roseburia in a univariate analysis (2.4 versus 1.2 percent); statistical significance was no longer seen after adjustment for covariates. Between the groups, multiple functional pathways were differentially enriched.

"Further investigation is needed to confirm these findings and determine whether modifying the gut microbiome could influence melanoma development and progression," the authors write. "The gut microbiome is a crucial piece of the puzzle in our health, therapy responses, and treatment outcomes. Witt et al. provide another piece of this puzzle by identifying key features of gut dysbiosis in patients with melanoma," Amrit K. Greene, M.D., and Amanda M. Nelson, Ph.D., of the Penn State College of Medicine in Hershey, Pennsylvania, write in a companion editorial.

Several study authors disclosed ties to the pharmaceutical industry.