Established and Potential Predictive Biomarkers in Gastrointestinal Cancer--c-Kit, Her2, Ras and Beyond.

BACKGROUND Gastrointestinal cancers are among the leading causes of cancer-related deaths worldwide. In different tumor types, personalized systemic treatment strategies based upon biomarker-selection were established over the last years. Although there is a flood of targeted agents in clinical development, only a few targeted agents with a predictive biomarker could be established for the treatment of patients with gastrointestinal cancer patients so far. SUMMARY Currently, predictive biomarkers for gastrointestinal cancers include Her2 overexpression or amplification (gastroesophageal adenocarcinoma), c-Kit overexpression (gastrointestinal stromal tumors) and RAS wild-type (colorectal cancer). Selection of patients based on these biomarkers allows the efficient use of targeted agents. The presence of a BRAF mutation and/or high microsatellite instability is prognostic and rather a predictive marker in CRC. Promising candidate markers in advanced clinical development are MET amplification in gastroesophageal adenocarcinoma, Met overexpression and high AFP serum levels in hepatocellular carcinoma. KEY MESSAGE Biomarker-guided systemic treatment is established in a subset of patients with gastrointestinal cancer. Ongoing clinical trials and further advances in high-throughput technologies will hopefully result in more personalized systemic treatment strategies for these patients in the near future.