Hu et al. found that, after transplantation of the gut microbiota from healthy mice or Lactobacillus reuteri to carcinogen-induced primary HCC-bearing mice, the proportion of IL17A-producing group 3 innate lymphoid cells in the liver was decreased, leading to the reduced IL17A production and suppressed HCC development.172 Li et al. examined the intratumoral microbiome in human HBV-related HCC and identified two microbiome-based HCC subtypes, defined as bacteria-dominant and virus-dominant subtype.173 Higher infiltration of M2 macrophage was associated with bacteria-dominant subtype. The gene discussed is IL17A; the disease is hepatocellular carcinoma.