In vivo, at two weeks after administrating MRC2-shRNA via the peritoneal cavity of the endometriosis-disease mouse model, the percentage of peritoneal Treg cells and Treg cells in ectopic lesions were significantly higher than that in the vector group (Figures 6h, i, l and m), and mainly comprised TGF-β1+ and CTLA-4+ Treg cells in the peritoneal fluid (Figures 6j and k). This evidence concerns the gene CTLA4 and endometriosis.