Remarkably, faecal transplantation from MR diet-fed tumour-free B6 mice was sufficient to induce a dramatic reduction of the fraction of CD3+ and CD8+ T cells in the blood and small intestine (Fig. 4b and Extended Data Fig. 5d) and increase the tumour number and burden in the intestines in recipient Apcmin+/− mice (Fig. 4c and Extended Data Fig. 5e). The gene discussed is CD8A; the disease is neoplasm.