The purpose of this investigation is to characterize the invasiveness of peritoneal and ovarian endometriosis patient-derived cell lines and endometrial stromal cells from endometriosis patients, relative to the invasiveness shown by the triple-negative breast cancer cell line (MDA-MB-231), a hormone-driven endometrial cancer cell line (EM-E6/E7/TERT), and a bone chondrosarcoma cell line (SW1353). This evidence concerns the gene TERT and endometriosis.