[Molecular targets for colon cancer. VEGF, EGFR - and what else?].

Colorectal cancer (CRC) is the second most common cancer in Germany; there are more than 70,000 new cases annually. It is most commonly a disease of the elderly, and its relative and absolute frequency has risen during the last decades. CRC remains a major clinical and health economy challenge. Progress has been made in patient management and CRC treatment. Screening colonoscopy was introduced in Germany in 2002, and five new therapeutic agents have been approved since 2001, i.e. capecitabine, oxaliplatin, cetuximab, bevacizumab and panitumumab; guidelines have been published, and 48 interdisciplinary CRC centres have been certified in Germany in compliance with DIN EN ISO 9001:2000. Despite these advancements, targeted treatment of CRC is still in its infancy. Until 2007, no predictive biomarkers were used to tailor the adjuvant or palliative chemotherapy of CRC. KRAS genotyping was recently introduced as predictive biomarker, since only tumors carrying a wildtype were found to respond to treatment with panitumumab. Among the tumors with KRAS wildtype, only 40-53% (equivalent to 20-30% of all CRC patients) will benefit from treatment, and the remainder are still enrolled for "non-targeted" treatment. Thus there is still a great need for predictive biomarkers that are able to tailor patient treatment at different stages of the disease.