The prognostic significance of type IV collagen expression in colorectal carcinomas

BACKGROUND: Breakdown of basement membrane is believed to be an essential step for tumor invasion and metastasis. The interaction between tumor cells and extracellular matrix can also result in induction of basement membrane synthesis by tumor and stromal cells. The aim of this study was to investigate distribution patterns of type IV collagen expression at the basement membrane in the tumor tissue of colorectal carcinomas by immunohistochemical staining. The degree of expression of type IV collagen correlated with classical clinicopathologic prognostic factors and their potential relationship with patients' prognosis. PATIENTS AND METHODS: This study included 40 patients who underwent curative resection of colorectal cancer at the Department of Surgery in the General Hospital Senta with complete follow-up for 5 years or until death. The identification of basement membrane was performed immunohistochemically using monoclonal antibodies to collagen IV. The basement membrane synthesis at the invasive front of colorectal cancer was semiquantitatively assessed as mild, moderate or severe. RESULTS: The deposition of basement membrane type of collagen IV had a statistically significant correlation with the stage of disease and histological grade of tumor with tendency of lesser synthesis of basement membrane in the advanced stage of disease and poorer histological grade of tumor. There were no significant correlations between intratumoral basement membrane synthesis and sex and age of patients, and localization and histological type of tumor. Five-year survival rates in patients with mild synthesis of basement membrane in colorectal tumor were significantly lower than in patients with severe expression of basement membrane. The basement membrane synthesis in colorectal cancer was a prognostic factor with significance behind stage of disease and histological grade of tumor by univariate Cox hazard-model. Multivariate Cox analysis verified that explicit synthesis of basement membrane showed a trend toward better prognosis, but it was not statistically significant. CONCLUSION Immunohistochemical staining for type IV collagen is an important additional technique with prognostic value.