ICOS and neoplasm: In the light of these findings, in vivo investigations of the effects of fiber-rich diet on immune responses defined by network analysis showed that species of the Ruminococcaceae family are fiber-fermenting bacteria producing significant amounts of SCFAs that can contribute to the accumulation of T cells in the tumor, such as CD4+ T cells, inducible T cell co-stimulator (ICOS)+ T cells, and CD8+ T cells, and engage pathways of T cell activation which mediate their anti-tumor effects [30].