Clinical significance of blood endocan level in breast cancer patients

Endocan expression has been associated with aggressive tumor progression and poor outcomes in various cancers. Our preclinical study demonstrated that endocan in the peripheral blood has the potential for use as a prognostic biomarker of triple-negative breast cancer （TNBC）. Currently, the clinical results of endocan in the blood collected from patients with breast cancer are extremely limited. Thus, this study aimed to examine the extent to which blood endocan correlates with the staging of cancer in such patients. A total of 54 patients with confirmed breast cancer who were treated at Showa University Hospital between 2020 and 2021 were included in this study. Blood was obtained from them, and the endocan level in plasma samples was measured using a commercial ELISA kit. The correlation between blood endocan level and clinicopathological characteristics was then determined. The higher the cancer staging, the higher the positivity rate of endocan in patients with luminal-type breast cancer, although no significant association was observed. The positivity rates of endocan at stages 0 and I were 17％ and 38％, respectively. However, no positivity was observed for serum carcinoembryonic antigen （CEA） or cancer antigen 15-3 （CA15-3）, indicating that endocan could be more sensitive than the frequently used tumor markers. The patient database demonstrated that the ESM1 gene expression was significantly higher at any stage in breast tumor tissue than in normal breast tissue. This study suggests that endocan is a potential candidate for a new, blood-based biomarker for breast cancer.