AIM:To analyze the pathogenetic role and potential clinical usefulness of the epidermal growth factor receptor(EGFR)and the human epidermal growth factor receptor 2(HER2)in patients with advanced biliary tract cancer(BTC). METHODS:EGFR and HER2 expression was studied in biopsy samples from 124 patients(51%women; median age 64.8 years),with advanced BTC diagnosed between 1997 and 2004.Five micrometers sections of paraffin embedded tissue were examined by standard, FDA approved immunohistochemistry.Tumors with scores of 2+or 3+for HER2 expression on immunochemistry were additionally tested for HER2 gene amplification by fluorescence in situ hybridisation(FISH).RESULTS:34/124 patients(27.4%)had gallbladder cancer,47(37.9%)had intrahepatic BTC and 43(34.7%)had extrahepatic or perihilar BTC.EGFR expression was examined in a subset of 56 samples. EGFR expression was absent in 22/56 tumors(39.3%). Of the remaining samples expression was scored as 1+in 12(21.5%),2+in 13(23.2%)and 3+in 9(16%), respectively.HER2 expression was as follows:score 0 73/124(58.8%),score 1+27/124(21.8%),score 2+ 21/124(17%)and score 3+4/124(3.2%).HER2 gene amplification was present in 6/124,resulting in an overall amplification rate of 5%. CONCLUSION:Our data suggest that routine testing and therapeutic targeting of HER2 does not seem to be useful in patients with BTC,while targeting EGFR may be promising. AIM: To analyze the pathogenetic role and potential clinical usefulness of the epidermal growth factor receptor (EGFR) and the human epidermal growth factor receptor 2 (HER2) in patients with advanced biliary tract cancer (BTC). METHODS: EGFR and HER2 expression was studied in biopsy samples from 124 patients (51% women; median age 64.8 years), with advanced BTC diagnosed between 1997 and 2004. Five micrometers sections of paraffin embedded tissue were examined by standard, FDA approved immunohistochemistry. Tumors with scores of 2 + or 3 + for HER2 expression on immunochemistry were further tested for HER2 gene amplification by fluorescence in situ hybridization (FISH) .RESULTS: 34/124 patients (27.4%) had gallbladder cancer, 47 (37.9%) had intrahepatic BTC and 43 The remaining samples were scored as 1 + in 12 (21.5%), 2+ in 13 (23.2%) and 3 + in 9 (16%), score 2 21/124 (17%) and score 3 + 4/124 (3.2%) respectively. .HER2 gene amplification was present in 6/124, resulting in an overall amplification rate of 5%. CONCLUSION: Our data suggest that routine testing and therapeutic targeting of HER2 does not seem to be useful in patients with BTC, while targeting EGFR may be promising.