Given that expression of TGFB1 is significantly different in peritoneum from sites distal to endometriosis lesions compared to sites adjacent to endometriosis lesions but there is no difference in peritoneal expression of TGFB1 between women with and without endometriosis lesions, it is likely to be the later and not a global change in the peritoneum of women with endometriosis. This evidence concerns the gene TGFB1 and endometriosis.