[Technical considerations for KRAS testing in colorectal cancer. The pathologist's point of view].

The KRAS status is now a mandatory prerequisite in order to treat metastatic colorectal patients with anti-EGFR (epidermal growth factor receptor) antibodies, such as cetuximab (Erbitux) or panitumumab (Vectibix). KRAS mutations are unambiguously linked to a lack of response to these targeted therapies and to a poor outcome. The optimal determination of the KRAS status should be based on coordination between pathologists and biologists. The pathologist must morphologically check the tumor to be analyzed and be sure that the fixatives used are valuable for molecular biology. The pathologist's involvement may also concern the DNA extraction and the KRAS mutations analyses. This involvement has to be included in a multidisciplinary setting in order to get rapid and robust tests for the clinical use. The imperative knowledge of the KRAS status in the management of metastatic disease represents a good example of this multidisciplinary coordination. In the future, the pathologist's role should be extended, considering the emergence of a more and more personalized medicine, integrating efficiency and cost-effectiveness. Thus, the pathologist may contribute to validate new molecular tests and to offer his specific techniques for translational research.