Infection with Helicobacter bilis but not Helicobacter hepaticus was Associated with Extrahepatic Cholangiocarcinoma

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.

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.

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.

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.