Distribution of basement membrane antigens in bladder carcinomas: an additional prognostic parameter. Immunohistochemical study.

A retrospective study of basement membrane (BM) components (laminin and type IV collagen) in urothelial tissues was performed by applying an immunoperoxidase method to 64 formalin-fixed specimens. The distribution of laminin and type IV collagen was investigated in normal and non-cancerous epithelium (11 cases), where the staining of the basement membrane was continuous. In the invasive bladder carcinomas (53 cases), two distinct staining patterns were observed both with type IV collagen and with laminin: preserved or thin and discontinuous (pattern I) and fragmented or absent (pattern II). These patterns were largely related to the type of growth of the bladder neoplasias ("pushing margin" or "finger-like") and to the cellular arrangement. Furthermore, five-year survival exceeded 70% in patients with pattern I, whereas only three of the 18 patients with pattern II survived for five years or more.