title: Infection with Helicobacter bilis but not Helicobacter hepaticus was Associated with Extrahepatic Cholangiocarcinoma.
abstract: OBJECTIVE
  The biliary tract cancer or cholangiocarcinoma (CCA) represents the sixth leading cause of gastrointestinal tumors in the Western world, and mortality varies across the world, with regions such as Chile, Thailand, Japan, and northeastern India presenting the highest rates. CCA may develop in the bile duct, gallbladder, or ampulla of Vater; and risk factors include obesity, parity, genetic background, geographical and environmental factors. Inflammation induced by bacterial infections might play a role in the pathogenesis of CCA. In this work, we investigated whether there is an association between extrahepatic cholangiocarcinoma (ECCA) and infection with S. typhi, H. hepaticus, or H. bilis in a Mexican population.
  
  
  METHODS
  A total of 194 patients were included and divided into 91 patients with benign biliary pathology (controls) and 103 with ECCA (cases). Tumor samples were taken during endoscopic retrograde cholangiopancreatography by biliary brushing, followed by DNA extraction and PCR testing for infections.
  
  
  RESULTS
  We found that 44/103 cases were positive for H. bilis, compared with 19/91 controls (p = 0.002; OR 2.83, 95% CI 1.49-5.32), and when analyzed by sub-site, H. bilis infection was significantly more associated with cancer in the common bile duct (p = 0.0005; OR 3.56, 95% CI 1.77-7.17). In contrast, H. hepaticus infection was not different between cases (17/103) and controls (13/91) (p = 0.82; OR 1.19, 95% CI 0.54-2.60). None of the samples were positive for S. typhi infection.
  
  
  CONCLUSIONS
  In conclusion, infection with H. bilis but neither H. Hepaticus nor S. typhi was significantly associated with ECCA, particularly with tumors located in the common bile duct.
authors.affiliation: Departamento de Anestesiología, UMAE 71 IMSS, Torreón, Coahuila, México.
authors.forename: Fany K
authors.initials: FK
authors.lastname: Segura-López
authors.affiliation: Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, IMSS, México City, DF, México.
authors.forename: Francisco
authors.initials: F
authors.lastname: Avilés-Jiménez
authors.affiliation: Departamento de Endoscopía Digestiva, UMAE 71 IMSS, Torreón, Coahuila, México.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Güitrón-Cantú
authors.affiliation: Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, IMSS, México City, DF, México.
authors.forename: Hilda A
authors.initials: HA
authors.lastname: Valdéz-Salazar
authors.affiliation: Departamento de Endoscopía Digestiva, ISSSTECH, Tuxtla Gutiérrez, Chiapas, México.
authors.forename: Samuel
authors.initials: S
authors.lastname: León-Carballo
authors.affiliation: Departamento de Endoscopía Digestiva, HGZ No. 35 IMSS, Juarez, Chihuahua, México.
authors.forename: Leoncio
authors.initials: L
authors.lastname: Guerrero-Pérez
authors.affiliation: Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Fox
authors.affiliation: Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, IMSS, México City, DF, México.
authors.forename: Javier
authors.initials: J
authors.lastname: Torres
mesh_terms: D000328:Adult; D000368:Aged; D001650:Bile Duct Neoplasms / Q000382:microbiology*; D017734:Bile Ducts, Extrahepatic / Q000382:microbiology; D001661:Biliary Tract Neoplasms / Q000382:microbiology*; D016022:Case-Control Studies; D018281:Cholangiocarcinoma / Q000382:microbiology*; D005260:Female; D016998:Helicobacter / Q000502:physiology*; D016481:Helicobacter Infections / Q000382:microbiology*; D044923:Helicobacter hepaticus / Q000502:physiology*; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged
keywords: Helicobacter bilis; Helicobacter hepaticus; bile duct; biliary tract; cholangiocarcinoma