MUC5AC and colorectal carcinoma: Inter-individual microbial community heterogeneity of the human gut is influenced by spatial distribution, micro-heterogeneity, host genetics, dietary preferences, and mucin content (Eckburg et al., 2005; Hong et al., 2011; Zhang et al., 2014), and has posed a long-standing challenge when investigating microbial signatures implicated in CRC tumorigenesis.