Ancestry-Dependent Immunologic and Prognostic Effects Characterize the Prostate Cancer Urinary Proteome.

Urine is an attractive biomarker analyte for non-invasive longitudinal monitoring of health and disease, particularly for diseases of the genitourinary tract, like prostate and bladder cancer. The composition of an individual's urine reflects both genetic and lifestyle characteristics that differ across geographies and populations, like diet, hydration and other socio-economic factors. While men of African ancestry have elevated prostate cancer risk, it is unclear to what extent this influences urinary biomarkers. We therefore quantified the urinary proteomes of 329 localized prostate cancer patients: 135 self-identifying as White and 194 self-identifying as Black. We identified 110 proteins that significantly differed between these groups after controlling for age, PSA, and cISUP. Immune pathways were particularly dysregulated. The urinary proteome of Black patients harboured more features of cancers presented as higher grade than those of grade- and PSA-matched White patients. These observations highlight the importance of controlling for race- and ancestry-associated differences in the development of urinary biomarkers.