Excess butyrate has been shown to impair DC-mediated tumor antigen cross-presentation: in a melanoma model, antibiotic depletion of butyrate-producing gut commensals led to heightened DC cross-priming of tumor antigens and stronger CD8+ T cell responses after radiotherapy, whereas reintroducing butyrate abrogated this effect [172]​. Here, CD8A is linked to melanoma.