Importantly, the combination of sEV protein LAMB1 and serum PSA was found to further improve the diagnostic value in the metastasis group compared to the control group (healthy and BPH participants) and localised primary PCa group up to AUC values 0.9905 (95% CI from 0.9657 to 1; P < 0.0001) and 0.9333 (95% CI from 0.8647 to 1; P < 0.0001), respectively. Here, LAMB1 is linked to benign prostatic hyperplasia.