Highly Sensitive DNA Testing of Fusobacterium nucleatum in Colorectal Tumors

Area of Science:

• Microbiology
• Genetics
• Oncology

Background:

• Fusobacterium nucleatum (Fn) is implicated in colorectal cancer (CRC) risk, progression, and specific tumor characteristics.
• Accurate and sensitive detection of Fn in tumor tissue is crucial for understanding its role in CRC.

Purpose of the Study:

• To develop and validate a sensitive and specific droplet digital PCR (ddPCR) assay for detecting Fn in human tissues.
• To evaluate the association between Fn enrichment in tumor tissue and clinicopathological features of CRC.

Main Methods:

• A ddPCR assay was developed targeting the Fn nusG gene, normalized to the human SLCO2A1 gene.
• The assay was applied to matched tumor and normal tissues from 613 participants in the Colon Cancer Family Registry.
• Logistic regression was used to analyze the odds of Fn enrichment in relation to tumor site, stage, and other factors.

Main Results:

• The ddPCR assay demonstrated high sensitivity and specificity, outperforming qPCR for low-level Fn detection.
• Fn was detected in 21% of tumor tissues and 10% of normal tissues, with enrichment observed in 19% of tumors.
• Fn enrichment was significantly associated with female sex and proximal colon tumors (OR=1.86).

Conclusions:

• A sensitive and specific ddPCR method for detecting Fn enrichment in human tissues was successfully established.
• ddPCR offers enhanced detection capabilities for Fn(nusG), benefiting studies on tumor-associated bacteria in CRC.