Ten proteins were targets for two (40 %) of the five CC sera: 3-ketoacyl-CoA thiolase, α-enolase, β-enolase, acetyl-CoA acetyltransferase, ATP synthase subunit β, catalase, epoxyde hydrolase, liver arginase, liver carboxylesterase 1 and retinal dehydrogenase. The gene discussed is CAT; the disease is cholangiocarcinoma.