Molecular biology and colorectal cancer:: An overview

Colorectal cancer is one of the leading causes of morbidity and mortality in Europe and the USA with about 300,000 new cases and 200,000 deaths each year. Moreover, genetic alterations are common in sporadic colorectal cancer, where 50% of all colorectal tumors exhibit K-ras mutations, and over 75% of all colorectal malignancies have DCC and p53 mutations. These results from basic research studies on colorectal tumors provide an excellent model and may have a major influence on clinical practice. Several studies have shown that the detection of K-ras mutations by polymerase chain reaction (PCR) in the stool of patients with colorectal cancer can serve as a new screening test. Another example for the influence of molecular biology on the treatment of colorectal cancer is given by the fact th at the absence of the DCC protein in cancer tissues by immunohistochemical analysis correlates with poor prognosis and may indicate the need for an adjuvant therapy. However, the most important impact will arise from the development of new treatment strategies such as gene therapy for which phase I trials have already been completed.