In Figure 7, from the arcs, the relationship between PTGS2 and BCHE was the strongest among all pairwise relationships, but also they formed a special Y structure [56] that indicates plausible causality, i.e., PTGS2 regulating BCHE. Similarly we have analyzed mRNA expression endometriosis data (Figure 7). This evidence concerns the gene PTGS2 and endometriosis.