In our cohorts, 75% of the TNBC samples overexpress RRAS2. Interestingly, the breast tumors that develop in our two RRAS2-overexpressing mouse lines correspond, according to immunohistochemical markers and the global transcriptome, to the basal subset of TNBC in humans, thus confirming the causal effect of RRAS2 overexpression in TNBC. Here, RRAS2 is linked to breast neoplasm.