Indeed, fecal samples of CRC patients contained higher abundancies of Akkermansia muciniphila, a mucin-degrader, and sulfate-reducing genera such as Atopobium, Bilophila, and Desulvofibrio. Higher abundancies of the latter coincided with increased hydrogen sulfide concentrations (Figure 2) [118]. Here, MUC5AC is linked to colorectal carcinoma.