ABSTRACT
Type F collagen is the major component of the basement membrane (BM) and is considered to act as a barrier during tumor invasion. In order to demonstrate the changes of type IV collagen in the BM. immunohistochemical methods were used in normal bladder and 27 cases of transitionral cell carcinoma (TCC) of the bladder for which clinical follow-up was available. Normal epithelial structures were urrounded by a generally intact BM type F collagen. In stage Ta lesion, type IV collagen was single layered but regular continuous linear fashion. In stage T1 or T2 lesion, they were partially disrupted in areas of invasion with irregular contour. In stage T3 lesion, type IV collagen was completely absent from BM. Above findings are very similar to our previous BM laminin study in bladder cancer. It supports the hypothesis that tumor cell conjugates with BM laminin and release the type IV collagenase which degrades the BM type IV collagen. In conclusion, it is suggested that both BM laminin and type IV collagen disappear in the area of invasion and the disappearance of BM type IV collagen in superficial disease may also provide early indication of invasive disease and careful monitoring ismandatory.