IL17A and neoplasm: Interestingly, the colonic mucosa biofilm in patients with familial adenomatous polyposis was reported to be composed mainly of E. coli and B. fragilis already at an early noncancerous stage (Dejea et al. 2018) and experimental colonization of tumor-prone mice with these bacteria resulted in an increase of IL-17 levels and DNA damage in colonic epithelium as well as in faster tumor onset and higher mortality (Dejea et al. 2018).