Coincidentally, loss of p16 expression in urothelial cells found in urine is a sensitive and specific clinically used biomarker for detection of urothelial cancers, and chromosome 9 deletion (where Cdkn2a resides) is one of the most frequent mutations associated with urothelial bladder cancer (Orlow et al., 1995; Wu et al., 2000). This evidence concerns the gene CDKN2A and bladder transitional cell carcinoma.