Molecular mechanisms and targeting of colorectal cancer.

Targeted therapies that are approved for metastatic colorectal cancer are divided into two groups: those affecting vascular endothelial growth factor (VEGF) known to interrupt tumor growth and metastasis (also called neo-angiogenesis), and agents that affect the tumor directly by interrupting the epidermal growth factor (EGF) and its receptor. Anti-angiogenic VEGF therapies are divided into two categories: one affecting the VEGF ligand, such as bevacizumab, and those that inhibit the VEGF receptor, such as PTK/ZK. Epidermal growth factor receptor (EGFR) therapies are divided into monoclonal antibodies that affect EGFR, such as cetuximab, and EGFR tyrosine kinase inhibitors, such as gefitinib. Both VEGF and EGFR areas of treatment have shown promising efficacy in first-line, combination therapy settings. Future targeted therapeutic strategies include gene profiling, combinations of capecitabine and oxaliplatin, with bevacizumab and/or cetuximab therapies.