P53 OVEREXPRESSION AND HUMAN PAPILLOMAVIRUS INFECTION IN TRANSITIONAL-CELL CARCINOMA OF THE URINARY-BLADDER - CORRELATION WITH HISTOLOGICALPARAMETERS

Seventy-nine transitional cell carcinomas (TCCs) of the urinary bladde r (25 grade 1, 22 grade 2, and 32 grade 3 tumours) mere examined for p 53 overexpression by immunohistochemistry with a monoclonal antibody a nd for human papillomavirus (HPV) infection by the polymerase chain re action (PCR), Positive immunostaining for p53 was detected in 40.5 per cent of the cases; the percentage of positive cases was significantly lower in low-grade (G1 and G2) TCCs than in high-grade (G3) tumours ( 10.6 per cent vs, 84.4 per cent; P<0.0001). The overall rate of HPV in fection was 32.9 per cent; 20.3 per cent of the cases were positive fo r HPV 16, 3.8 per cent for HPV 18, and 8.9 per cent for both, Consensu s primers as well as type-specific primers for HPV types 6, 11, and 33 failed to detect any additional case with HPV infection, The prevalen ce of HPV 16 and/or HPV 18 infection was significantly higher in low-g rade than in high-grade tumours (44.7 per cent vs, 15.6 per cent; P=0. 0061). p53-positive cases mere more common among papillary, deeply inf iltrating tumours, and HPV-positive cases among papillary, non-infiltr ating lesions, According to these data, p53 overexpression and HPV 16/ 18 infection are common findings in bladder TCC and there appears to b e an inverse correlation of p53 overexpression and of HPV infection wi th tumour aggressiveness, The possibility of different molecular pathw ays in superficial low-grade and in invasive high-grade tumours is sug gested.