Changes in SV40 large T antigen-driven tumour-associated microbiota were more resembling with Pten−/−; Rb1−/−-related microbiota than Pten−/−; Rb1+/+, again supporting that Rb1 loss of function is prompting the growth of larger tumours resulting in more significant gut microbiota alterations. The gene discussed is RB1; the disease is neoplasm.