As shown in Figure 3, with a few exceptions,23, 24 studies showed that levels of typical Th2 cytokines (e.g., IL‐4, IL10, IL‐13, or TGF‐β) in serum, peritoneal fluid, and ectopic lesions of patients with endometriosis were higher than those of normal patients, whereas levels of typical Th1 cytokines (e.g., interferon‐γ [IFN‐γ] or IL‐12) were suppressed.18, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37. Here, TGFB1 is linked to endometriosis.