As the previously tested Rag2-/-γc-/- mice were no longer available in our animal house (see section “Materials and Methods”), we used brand new mice with identical knock-out genes (BALB/c Rag2-/-γc-/-, BRG), but obtained from a different source and with a well-defined, restricted microbiota, that were endowed with high susceptibility to tumor xenoengraftment (Yamamoto and Schiestl, 2014; Rosshart et al., 2017). Here, RAG2 is linked to neoplasm.