Fig. 1

Schematic diagram illustrates the localization of endometrial stem/progenitor cells and the hypothesis that stem cells in RM, BMDSCs and CECs may be involved in the development of endometriosis. CD140b⁺CD146⁺ eMSCs are located perivascularly in both the functionalis and basalis. SUSD2⁺ eMSCs are also perivascular cells. Epithelial progenitor cells are a subset of SSEA-1⁺ cells located at the bottom of basalis, and may form individual colonies. Endometrial SPs are composed of heterogeneous populations, including endothelial cells and CD140b⁺CD146⁺ eMSCs. Endometrial stem/progenitor cells in RM may be the cellular source of primary endometriotic lesions. Abnormal endometrial stem/progenitor cells in RM enter the pelvic cavity and invade the mesothelium. On one hand, endometriotic cells secrete cytokines (such as CXCL12) to attract limited BMDSCs in blood circulation and implant them in the ectopic lesions. On the other hand, endometriotic cells enter the blood circulation to cause distant infiltration