The concentration levels of the three circulating proteins inversin, gelsolin, and apolipoprotein A1 identified high-grade bladder cancer with an AUC > 0.84 (95% confidence interval 71–98), 0.76 (95% confidence interval 61–92%), and 0.90 (95% confidence interval 82–98), respectively. This evidence concerns the gene GSN and urinary bladder cancer.