The abundance of key enzymes required for de novo lipogenesis, including sterol regulatory element-binding protein (SREBP1, SREBP2) and fatty acid synthase (FASN) was reduced in Pparγ1−/− vs. Pparγ1+/+ ErbB2 mammary tumors (Figure 1I–K and Figure S1B). This evidence concerns the gene SREBF1 and breast cancer.