Besides, PTGDS-PGD2 could suppress tumor growth by inhibiting the phosphorylation and nuclear expression of STAT3 in gastric cancer [14], reducing the expression of transcription factor TWIST2 in breast cancer [35], and activating PPARγ ligand-binding domain and the peroxisome proliferator response element reporter systems in prostate tumor [13]. This evidence concerns the gene PPARG and breast cancer.