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AACR 2023: Microbial Dysbiosis in Extrahepatic Cholangiocarcinoma

By: Vanessa A. Carter, BS
Posted: Thursday, May 11, 2023

Although there is increasing evidence that gut microbial dysbiosis is related to biliary disease and cancer, the association between tumor and gut microbiome environments in biliary cancer remains unclear. Consequently, Kang et al, of the Chungnam National University Hospital, Daejeon, Republic of Korea, and colleagues compared the microbiome from stool and tissue samples of patients with extrahepatic cholangiocarcinoma and healthy donors. The results of this study were presented during the American Association for Cancer Research (AACR) Annual Meeting 2023 (Abstract 5903/14).

“To the best of our knowledge, this study is the first that compares the microbiome of tissues and stools from extrahepatic cholangiocarcinoma patients and healthy controls; the extrahepatic cholangiocarcinoma patients and healthy controls showed different microbiota profiles,” the researchers concluded. “Further studies are needed to investigate the clinical implications of microbial dysbiosis in biliary tract cancer and formulate novel microbiome-based treatments.”

The investigators focused on 24 individuals; 13 had extrahepatic cholangiocarcinoma and 11 were healthy controls. From swab and fecal samples, the bacterial 16S ribosomal RNA gene was amplified by polymerase chain reaction and sequenced using Illumina MiSeq.

Swab samples from patients with extrahepatic cholangiocarcinoma demonstrated significantly lower alpha diversity compared with controls (P < .001). The most common phylum in patients with cancer was proteobacteria (53%), whereas firmicutes (79%) and actinobacteria (13%) were most common in controls. Streptococcus (25.1%), Escherichia shigella (16.9%), and Enterococcus (13.9%) were found in patients with extrahepatic cholangiocarcinoma; Blautia (12%), Limosilactobacillus (12%), and Bifidobacterium (19%) were observed in controls.

Streptococcus (12.5%) and Bacteroides (8.2%) were most common in the fecal samples of patients with extrahepatic cholangiocarcinoma; Blautia (13.8%) and Faecalibacterium (11.5%) were the most common among control fecal samples. Of note, the principal coordinate analysis plot of fecal samples demonstrated significant differences in microbiota composition between patients with cholangiocarcinoma and healthy controls (P = .001).

Disclosure: The study authors reported no conflicts of interest.

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