Campylobacter Presence in CRC Found to Accelerate Tumor Metastasis

While tumors linked to several forms of cancer, in particular colorectal cancer (CRC), are known to contain intratumoral and intracellular bacteria, the physiological consequences of these microorganisms are not well known.

In a recent study overseen by Christian Jobin, PhD, UF College of Medicine, campylobacter bacteria have been found to be enriched in primary CRC lesions of patients with metastasis.

Primary CRC tissue was collected from 34 chemotherapy-naïve patients who had experienced distant metastasis within 3 years (metastasis group), and from 37 patients who were metastasis-free (non-metastasis group) during 3 years’ follow-up. 16S ribosomal RNA gene sequencing was performed on each sample.

A linear discriminant analysis effect size analysis found a significant enrichment of campylobacter in the metastasis group. Patients who were determined to have intratumoral campylobacter (n=33) had a significantly poorer prognosis than patients with no detectable levels of campylobacter (n=38).

A validation cohort using a publicly available database consistently found that intratumor campylobacter was enriched in pre-operative metastasis patients. Using a dataset containing 1123 primary colorectal tumor samples from the UC San Diego Cancer Microbiome, and the Hartwig Medical Foundation dataset containing 527 metastatic CRC samples, the presence of campylobacter in both CRC and metastatic CRC was confirmed, with a higher abundance in the metastatic CRC cohort.

An intratumoral presence of campylobacter can accelerate tumor metastasis, which can potentially lead to a new diagnostic and therapeutic avenue for the management of CRC.