Abstract Background Endometrial cancer is the most common gynecological malignancy; however, there is no useful blood diagnostic biomarker. This study aimed to determine the utility of tissue factor pathway inhibitor 2 (TFPI2), a biomarker of ovarian cancer, as a diagnostic marker for endometrial cancer. Methods We examined serum TFPI2 levels in patients with endometrial cancer (n = 328) compared to those in healthy controls (n = 65) and evaluated the performance of serum TFPI2 levels as a diagnostic marker. We investigated the clinicopathological characteristics of patients with TFPI2-negative and TFPI2-positive endometrial cancer. Using immunohistochemistry (IHC), we examined TFPI2 expression in tumor tissues of 105 patients with type II endometrial carcinoma and evaluated the correlation between serum and tissue TFPI2 positivity. Results Patients with endometrial cancer had significantly higher serum TFPI2 levels than controls (196.7 pg/mL vs. 83.3 pg/mL; p 0. There was no significant difference in the immunostaining score according to histological type. Serum TFPI2 levels and immunostaining score showed poor agreement (kappa coefficient, -0.039). Conclusions The serum TFPI2 level is a promising marker for diagnosing and predicting the prognosis of endometrial cancer. No correlation exists between serum and tissue TFPI2 levels. Further multicenter clinical trials are needed to test the utility of TFPI2 as a diagnostic marker.
