Eidukaite et al. [11] implicated the Fas–FasL mechanism in the pathophysiology of early endometriosis by reporting a cytometric decrease in CD56dim NK cells (24.0% ± 4.9% vs. 36.3% ± 15.9%, p < 0.02), and an increase in CD95 (Fas antigen that promotes NK apoptosis) (66.6% ± 10.6% vs. 42.4% ± 10.1%, p < 0.01) in the peritoneal fluid of subjects with early endometriosis. This evidence concerns the gene FASLG and endometriosis.