Objective: To investigate the histological evidence of high risk human papillomavirus infection in bladder cancer.
Methods: 52 cases of papillary transitional cell carcinoma of the urinary bladder were studied for the incorporation of high risk human papillomavirus type 16 and type 18 DNA by non-isotopic in situ hybridization (NISH).
Results: 19 of 52 cases (36.5%) were positive for HPV DNA with punctuate and/or diffuse purple-blue staining in the nucleus of cancer cells, including two cases positive both for HPV16/18. HPV DNA were predominantly expressed in superficial tumors. Among these positive tumors, adjacent normal epithelium and Brunn's nests also showed positive staining. Morphologically, HPV positive cells existed in the whole layer of papillary tumor cells, 3 of them presented koilocytoid change.
Conclusions: HPV infection might be a common event in urinary bladder and a potential factor for carcinogenesis of bladder cells.