The expression of p53, Ki-67 and urokinase plasminogen activator receptor in colorectal adenomas with true invasion and pseudoinvasion

The recognition of pseudoinvasion is important in the differential diagnosi s of adenocarcinoma in patients with adenomas. This distinction might occas ionally be difficult, particularly when the dysplasia is pronounced. The pr esent study was undertaken in order to investigate whether the immunohistoc hemical expression of p53, Ki-67 and the urokinase plasminogen activator re ceptor (uPAR) was different in adenomas with true invasion and pseudoinvasi on. We studied 26 formalin-fixed, paraffin-embedded tumor samples, consisti ng of 10 cases of adenomas with pseudoinvasion and 16 cases of adenocarcino mas in adenomas. In this series of selected histologically typical cases a constant moderate or strong reaction for uPAR was present at the invasive f ront in all of the 16 adenomas with adenocarcinoma, but only focally in one of 10 adenomas with pseudoinvasion. The reactions for p53 and Ki-67 showed only minor differences. In conclusion, the immunohistochemical reaction fo r uPAR seems to be a useful supplement in cases without typical histology o r with severe dysplasia.