SOX2 and breast neoplasm: To better classify the mouse breast tumors arising in RRAS2-overexpressing mice into a molecular subtype and gain a preliminary understanding of the alterations induced by RRAS2 overexpression, we conducted RNAseq analysis on 15 independent tumors that emerged in 8 Rosa26-RRAS2fl/fl mice (2 MMTV-Cre + , 4 Sox2-Cre + , 2 Wap-Cre + : Table 1) and 9 samples of normal mammary gland tissue (2 non-transgenic nulliparous females, 3 non-transgenic breeders, 2 Cre—Rosa26-RRAS2fl/fl nulliparous females, and 2 Cre—Rosa26-RRAS2fl/fl pregnant females: Table 1).