IL17A and colorectal carcinoma: F. nucleatum is an intriguing target for CRC diagnostics and therapeutics, particularly as epidemiological studies have found that tumoral fusobacterial load is associated with poorer patient prognosis and recurrence after treatment.42,43 In this work, we used murine gnotobiotic models to reveal that F. nucleatum colonization increases colonic Il17a expression, intestinal Th17 cell frequency and IL-17-family cytokine production, reminiscent of how ETBF promotes tumorigenesis and suggesting a convergent mechanism between these two CRC-associated microbes.