Our analysis indicates that Th17/Treg cell balance is crucial in understanding endometriosis-associated ovarian cancer (EAOC), leading us to collect formalin-fixed, paraffin-embedded (FFPE) samples of EAOC, EM, and normal endometrium for immunohistochemistry evaluations of CXCL12, FOXP3, STAT3, and IL17. This evidence concerns the gene FOXP3 and ovarian cancer.