Precise capture of circulating endometrial cells in endometriosis

Endometriosis (EM) is a complex benign gynecological disease, but it has malignant biological behavior and can invade any part of the body. Clinical manifestations include pelvic pain, dysmenorrhea, infertility, pelvic nodules, and masses. Our previous study successfully detected circulating endometrial cells (CECs) in the peripheral blood of patients with EM. The purpose of this study is to overcome the limitation of cell size in the previous microfluidic chip method, to further accurately capture CECs, understand the characteristics of these cells, and explore the relationship between CECs and the clinical course characteristics of patients with EM.

Human peripheral venous blood used to detect CECs and circulating vascular endothelial cells (CVECs) was taken from EM patients ( n = 34) hospitalized in the Peking University People's Hospital. We used the subtraction enrichment and immunostaining fluorescence in situ hybridization (SE-iFISH) method to exclude the interference of red blood cells, white blood cells, and CVECs, so as to accurately capture the CECs in the peripheral blood of patients with EM. Then we clarified the size and ploidy number of chromosome 8 of CECs, and a second grouping of patients was performed based on clinical characteristics to determine the relationship between CECs and clinical course characteristics.

The peripheral blood of 34 EM patients and 12 non-EM patients was evaluated by SE-iFISH. Overall, 34 eligible EM patients were enrolled. The results showed that the detection rates of CECs were 58.8% in EM patients and 16.7% in the control group. However, after classification according to clinical characteristics, more CECs could be detected in the peripheral blood of patients with rapidly progressive EM, with a detection rate of 94.4% (17/18). In total, 63.5% (40/63) of these cells were small cells with diameters below 5 microm, and 44.4% (28/63) were aneuploid cells. No significant association was found between the number of CECs and EM stage.

The number and characteristics of CECs are related to the clinical course characteristics of patients with EM, such as pain and changes in lesion size, and may be used as biomarkers for personalized treatment and management of EM in the future.