Collagen IV staining pattern in bladder carcinomas: relationship to prognosis.

A prospective study of type IV collagen in urothelial tissues was undertaken using an immunoperoxidase method on 125 ethanol fixed specimens. In normal and non cancerous urothelium, the basement membrane was continuously stained and the same pattern was seen in the 27 superficial carcinomas. In the 48 invasive bladder carcinomas, we observed two patterns of staining for collagen IV: in the first one, the staining line was conserved or partially fragmented (28 tumours), while in the second one the staining line was widely fragmented or absent in more than 5% of the tumour area (20 tumours). We found a highly significant statistical correlation between the pattern of staining and short term prognosis. Twenty-nine patients had an assessable follow-up of three years at least. All 16 patients with pattern I staining were alive at two years while only two out of 13 patients with pattern II staining survived two years (P less than 0.0001). At three years, all the patients with pattern II staining died while 11 patients with pattern I were still alive (P less than 0.001). These data provisionally indicate that the type IV collagen staining pattern may be of prognostic value in assessing the short term behaviour of invasive bladder carcinomas. It is thus logical to envisage that the treatment decisions may be influenced by the results of collagen IV staining.