ERBB2 and cholangiocarcinoma: Specifically, mutations associated with cholangiocarcinoma are classified as ready for routine use (i.e., IDH1 mutations, FGFR2 fusions, high microsatellite instability, and NTRK fusions), undergoing experimentation due to the unknown extent of the benefit (i.e., BRAF V600E mutations), and hypothetical target due to clinical studies in other tumor types or similar molecular alterations (i.e., HER2 alterations).