We further analyzed the expression of four potential co-diagnostic genes in SLE and endometriosis, the results showed that QSOX1 and SP110 were significantly upregulated in both SLE and endometriosis group than in the normal group, and REV3L was significantly downregulated in both SLE and endometriosis group, while the expression of PMP22 was opposite in the SLE group (downregulated compared to the normal group), and endometriosis group (upregulated compared to the normal group) (Figure 4f, g). This evidence concerns the gene QSOX1 and endometriosis.