RAS wild-type colorectal cancer is frequently treated with anti-EGFR monoclonal antibodies; however, primary and acquired resistance rates remain a major limitation to clinical outcomes. Recent evidence suggests that Fusobacterium nucleatum colonization acts as a resistance factor to conventional chemotherapy through the induction of autophagy. This project aims to address the current scientific gap regarding the impact of this bacterium on the response to EGFR inhibitors. The study includes absolute quantification of bacterial 16S ribosomal RNA by droplet digital polymerase chain reaction (ddPCR) and its association with clinicopathological variables, overall survival, progression-free survival, and molecular profile (BRAF, TP53, PIK3CA, and MSI). Additionally, in an exploratory approach, the study will perform a comparative investigation of microbial colonization dynamics between primary tumor sites and their corresponding metastatic lesions using paired tissue samples.
