XCL1 and endometriosis: We found that the gene expression of GZMB was significantly down-regulated (0.546 ± 0.079 vs. 1.300 ± 0.278, P = 0.0149) while XCL1 was up-regulated (3.889 ± 0.466 vs. 1.672 ± 0.238, P = 0.0006) in endometriosis compared to that of control groups (Fig. 6e).