Immunocytochemical detection of p53 in cultures of exfoliated cells from urine of patients with urothelial cancers.

Early diagnosis of urothelial cancer is critical for successful treatment. Mutation of the p53 gene together with allelic loss of chromosome 17p correlates well with high grade and invasiveness of urothelial cancer. Moreover, this mutation is reported to be an early event for carcinoma in situ of the urothelium. In order to develop a new non-invasive diagnostic method for urothelial cancer, we have established a short-term culture system for urinary exfoliated cells from patients with urothelial cancer. Immunocytochemical detection of p53 in these urine-derived cells was conducted. Short-term cultures of exfoliated cells from 50 ml samples of urine from 52 patients with urothelial cancers were made. Adequate cell growth (> 10(5) cells per flask) was followed by passage onto glass chamber slides for p53 immunocytochemical staining. Successful passage was obtained in 40 of the 52 (76.9%) patients with urothelial cancers studied. The success rate for patients with tumors immunohistochemically positive for p53 nuclear accumulation was 90.5%, and 61.3% for those with tumors negative for p53 (P < 0.05). Results of immunochemical analysis of the p53 in the urine cells and those in the tumor samples were identical in 92.1% of the patients. Culture of exfoliated cells from urine would be a good, non-invasive method for the molecular diagnosis of urothelial cancer that should prove useful for the early detection and follow-up of tumors with p53 mutation.