The molecular basis of colorectal cancer

Colorectal cancers, whether sporadic or hereditary, are caused by a defined set of molecular events. The genes and pathways involved in the earliest s teps of tumorigenesis have crucial functions in the regulation of normal cr ypt homeostasis. Further insight into these pathways can lead to the develo pment of useful prognostic indicators, and target preventive and therapeuti c strategies in the management of colorectal cancer. Mutations in the APC/ beta -catenin/Tcf-4 pathway lead to important changes in stem cell dynamics , before clinically identifiable lesions appear. Preventive strategies aime d at reversing these changes or therapeutic interventions targeting cell po pulations with these alterations should be most efficacious.