CDKN2A and urothelial carcinoma: Our study results showed that loss of p16 gene expression was associated with low-grade urothelial carcinoma, while p16 gene amplification suggested the presence of high-grade urothelial carcinoma; importantly, a poor prognosis prodictof urothelial carcinoma in the urine specimen requires both positive p16INK4a protein expression and a high score of the p16 FISH test in the same specimen.