The interplay of genetic predisposition, altered gut microbiome, and delayed infection in development of pB-ALL. Schematic representation of results of study by Vicente-Dueñas et al: Pax5^+/− mice with abnormal B lymphoid development have a genotype-specific gut microbiome in a pathogen-free environment. The microbiome gets further altered when the mice are transferred to conventional facility (CF) housing before the development of pB-ALL. Depletion of the genotype-specific microbiome with antibiotics does not prevent pB-ALL in CF but leads to development of pB-ALL in pathogen-free facilities.