CXCL8 and colorectal carcinoma: In CRC, we found that Anaerolineae and TM7—oral microbes that also inhabit the human gastrointestinal tract, and are known to promote oral and colorectal tumorigenesis58–60—are negatively correlated with host genes enriched in the tumour-promoting interleukin-10 signalling pathway, such CXCL8 and IL1RN (Fig. 3c and Extended Data Fig. 2).