Urinary Microbiome as a Biomarker for Melanoma Diagnosis and Response Prediction to Systemic Tumour Therapy

This pilot study investigates the urinary microbiome as a potential non-invasive biomarker in patients with melanoma undergoing systemic therapy. It aims to determine whether microbial composition in urine differs between melanoma patients and matched controls, and whether it is associated with and predictive of response to immune checkpoint inhibition or targeted therapy.

In a prospective observational matched cohort design, melanoma patients initiating systemic therapy and control participants are recruited. Patients provide urine and stool samples at baseline and at two follow-up time points during therapy, along with clinical and lifestyle data, while controls provide a single urine sample and questionnaire data. Microbiome profiling is performed using 16S rRNA gene sequencing, followed by bioinformatic and statistical analyses to assess microbial diversity, composition, and associations with clinical variables.

The study evaluates differences in urinary and gut microbiome composition between patients and controls, longitudinal changes during therapy, and associations with treatment response. Statistical approaches include matched analyses, correlation and regression models, and receiver operating characteristic analyses to assess the predictive potential of microbiome-derived biomarkers.

This study is expected to provide first insights into the role of the urinary microbiome in melanoma and its potential utility as a biomarker for diagnosis and prediction of therapeutic response, contributing to the development of personalized treatment strategies.

Inclusion criteria

• melanoma with indication for systemic therapy
• age above 18
• informed consent

Exclusion criteria

• - inability to provide informed consent
• antibiotic use (except for topical use) ≤ 8 weeks prior to screening
• consumption of probiotic or prebiotic supplements within 4 weeks prior to screening
• current diagnosis of any disease with systemic inflammation (e.g. cellulitis, herpes zoster, psoriasis, etc.)
• for the case group: diagnosis of any active malignancy other than melanoma (except for basal cell carcinoma)
• for the control group: diagnosis of any active malignancy (except for basal cell carcinoma)