 Very preliminary and sparse data from a recent small phase II study with cetuximab do not allow to speculate whether the RAS status does predict the response in cholangiocarcinomas similarly to colorectal cancers Gruenberger et al. 2009. However, due to the clear evidence of absence of efficacy in mutant KRAS colorectal cancer, the presumptive population enrichment should be applied in this first trial on biliary duct cancer, which is to focus on KRAS wild type patients. 