Overexpression of cathepsin B correlates with angiogenesis in colon adenocarcinoma.

Some studies have shown the influence of proteases and vascular density in colorectal primary tumors on spreading and on the course of colorectal cancer. In the present study we have analyzed the relationships between overexpression of cathepsin B protein and angiogenesis intensity in resected colon tumors and their impact on prognosis. It has been investigated in a series of 90 colon cancer patients. Immunohistochemistry was used to evaluate cathepsin B overexpression in cancer cells and to visualize microvessels with antibodies against von Willebrand factor. Overexpression of cathepsin B was observed if more than 50% of cancer cells in searched field showed immunoreactivity with antibody against cathepsin B. Intensity of angiogenesis was evaluated as a mean number of microvessels from three fields with highest vessel number. In 36 cases (40%) overexpression of cathepsin B was detected. Increased angiogenesis (above median 31 vessels per 0.785 mm2) correlated positively with cathepsin B overexpression (p=0.0006). Higher vascular density associated with the presence of metastases in regional lymph nodes (p=0.01). Overexpression of cathepsin B was observed more often in group of older people (age above median 65 years; p=0.005). According to univariate analysis metastases in regional lymph nodes (p=0.0007), increased angiogenesis (p=0.0085), and distant metastases (p=0.02) were the features potentially influencing prognosis. Multivariate analysis revealed independent prognostic value only in case of metastases in regional lymph nodes (p=0.013) and when distant metastases were present (p=0.021), but not when increased angiogenesis in primary colon adenocarcinoma was observed (p=0.078). In conclusion we can say that there is a close relationship between intensity of angiogenesis and overexpression of cathepsin B protein in cancer cells in resected colon adenocarcinoma.