Immunohistochemical assessment of basement membrane components in colorectal cancer: prognostic implications.

Loss of basement membrane integrity during neoplastic invasion may have some direct prognostic significance, which is worth investigating. We studied 151 cases of colorectal adenocarcinomas retrospectively. The aim of the study was to investigate the immunohistochemical expression as well as the distribution of laminin and collagen IV within the basement membranes of cancer cell formations. The results were related to histological grade of malignancy (I, II or III) and Dukes' staging of all tumours as well as to 3-year survival status in 52 patients. Using the immunostaining method of strept ABComplex/HRP and appropriate monoclonal or polyclonal antibodies, we assessed the continuity, the discontinuity of the distribution or the total loss of structural basement membrane components alongside the infiltrating borders of each tumour. The results were evaluated statistically. Either a considerable degree of discontinuity or a total loss of basement membrane components was more common in moderately and poorly differentiated adenocarcinomas (p = 0.002 and p = 0.005 for collagen IV and laminin, respectively) and they seemed to be adversely associated with survival status (p = 0.066 and p = 0.014 for collagen IV and laminin, respectively). Interestingly, no association with the stage of disease was noticed. The results of this study reinforce the value of laminin and collagen IV as possible prognostic factors independently to tumour stage. The total loss or considerable discontinuity of the basement membranes of cancerous cells can be considered as indicators of tumour aggressiveness.