Variation in Molecularly Defined Prostate Tumor Subtypes by Self-identified Race

Background: Socioeconomic and health care utilization factors are major drivers of prostate cancer (PC) mortality disparities in the USA; however, tumor molecular heterogeneity may also contribute to the higher mortality among Black men.Objective: To compare differences in PC subtype frequency and genomic aggressiveness by self-identified race.Design, setting, and participants: Five molecular subtype classifiers were applied for 426 Black and 762 White PC patients in the Decipher Genomics ResourceOutcome measurements and statistical analysis: Differences in subtype frequency and tumor genomic risk (Decipher score >0.6) by race were evaluated using v2 tests and multivariable-adjusted logistic regression models.Results and limitations: Subtype frequencies differed by race for four classifiers. Subtypes characterized by the presence of SPOP mutations, SPINK1 overexpression, and neuroendocrine differentiation were more common among Black men. ERG and ETS fusion-positive subtypes were more frequent among White men, with no clear differences for subtypes reflecting luminal versus basal lineage. The hypothesized low-risk Kamoun S2 subtype was associated with a lower Decipher score among