Possible role of differential metalloproteinase 1 expression in signet ring cell and intestinal colorectal carcinoma histotypes

Background: Pure signet ring cell colorectal carcinoma ( SRCC) is an infrequent and highly malignant histological variant of colorectal cancer (CRC), while it is present as a histological component in colorectal carcinomas more frequently. Materials and Methods: The aim of this was to widen the knowledge of the biological factors involved in the pathogenesis and aggressiveness of SRCC by the identification and evaluation of possible molecular abnormalities. By means of immunohistochemistry the expression of the proteolytic degradation enzyme matrix metalloprotease (MMP)-1, that is a collagenase specifically degrading collagens I, II, III and of the adhesion proteins E-cadherin, B-catenin and fibronectin which are usually involved in the carcinogenesis of conventional colorectal tumours was investigated. Results: SRCCs showed a significantly greater MMP-1 expression compared to the ordinary intestinal colorectal cancer (ICRC) and a significantly reduced E-cadherin, β-catenin and fibronectin expression. Conclusions: The biological aggressiveness and strong metastatic behaviour of SRCC could be due to high MMP-1 and low expression of the adhesion molecules.