To investigate the role of TNFAIP3 in FGFR1-promoted breast tumor growth in vivo, we injected DCIS-iFGFR1 #2 parent control cells and TNFAIP3 KO DCIS-iFGFR1 cells into the fat pads of nude mouse mammary glands. Here, FGFR1 is linked to ductal breast carcinoma in situ.