The assessment of matrix metalloproteinase-9 expression and angiogenesis in colorectal cancer.

Colorectal cancer (CRC) is one of the most frequent types of cancer in the world. Between tumor cells and the stroma mutual interconnections are established that favors the tumor development and metastasis. In this respect, the extracellular matrix is remodeled so that it may become totally different from a morphologic perspective than the stroma of the organ in which the tumor develops. Matrix metalloproteinases (MMPs) have an essential role in the remodeling of the tumor stroma. We assessed the expression of MMP-9 on a number of 31 stage III colorectal adenocarcinomas. Generally, MMP-9 had a high but inconstant expression in tumor cells. The highest expression was found in poorly and moderately differentiated carcinomas, with a lower expression in well-differentiated colorectal cancers. Occasionally, MMP-9 expression was identified also in peritumoral macrophages and in stromal cells. Metastasis-free lymph nodes had an intense positive reaction in both macrophages and lymphocytes. The intensely positive reaction was observed for the macrophages and lymphocytes in the tumor necrosis regions. The process of angiogenesis was generally correlated with the intensity of MMP-9 reaction.