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514This study included a total of 46 patients diag-nosed with esophageal cancer who underwent radical esophagectomy with three-field lymph-adenectomy via a right thoracotomy and laparotomy at Juntendo University Hospital between September 2005 to December 20066). Written informed consent was obtained from all enrolled patients. This study was conducted within the guidelines set by the Declaration of Helsinki and approved by the ethical committee of Juntendo Hospital (No. E21-0253). Blood was collected just before surgery. A total of 10 mL of collected blood was centrifuged, and the obtained serum was stored at -80℃.The serum LR11 levels were measured by the sandwich enzyme-linked immunosorbent assay (ELISA) described below using anti-LR11 mono-clonal antibodies. A total of 100 μL of eight-fold diluted serum was dispensed into three wells of an antibody-binding plate (anti-LR11 mouse mono-clonal antibody, Sekisui Medical Co., Ltd., Tokyo) that was then left at room temperature (18-26℃) for 2 h. The liquid in the well was discarded, and the well was washed with 350 μL of cleaning solu-tion (buffer solution, Sekisui Medical Co., Ltd., Tokyo). The washing solution was removed, and 100 μL of biotin-labeled antibody solution was added and left at room temperature for 1 h. The solution in the wells was then removed, and then the wells were washed. After washing, 100 μL of tetramethylbenzidine solution (Sekisui Medical Co., Ltd., Tokyo) was added and left to stand at room temperature, away from light to luminesce. Next, 100 μL of stop solution (sulfuric acid, Sekisui Medical Co., Ltd., Tokyo) was added to stop the reaction. A microplate reader was used to measure the absorbance at a wavelength of 450 nm.The serum LR11 concentration measured by same method was reported around 10 ng/mL in most healthy individuals7, 8); thus, we divided the patients into a low LR11 group (LR11 levels below 10 ng/mL) and a high LR11 group (LR11 levels of 10 ng/mL or higher) and compared the two groups.We examined the relationship between LR11 levels and clinicopathological findings of esophageal cancer. Additionally, we also examined its relation-ship with serum total protein (TP) level and albumin (Alb) level, which reflect nutritional status, and serum total triglyceride (TG) level and total cholesterol (T-Cho) level in serum. Treatment strategies were decided according to the Union for International Cancer Control (UICC) TNM classifi-cation 7th edition for esophageal cancer9) in 2005 to 2006, so we analyzed based on this staging. Japa-nese Classification of Esophageal Cancer 11th edition was used for tumor location and vascular invasion evaluation10, 11）. For statistical analyses, we used Kruskal- Wallis test and the Kaplan-Meier esti-mate for survival analysis (IBM SPSS Statistics ver.26).Patients’ characteristicsPatients’ characteristics are shown in Table 1. The serum LR11 levels ranged from 2.75 ng/mL to 21.4 ng/ mL. The average value across all patients was 6.86 ng/mL, and the standard deviation was 3.68 ng/mL (Figure 1).After dividing the patients into the low-and high-LR11 level groups (cutoff value of LR11: 10 ng/mL), there were 39 patients in the low LR11 group and seven in the high LR11 group. There were no significant differences between the two groups in patients’ characteristics. Relationship between serum LR11 levels and pT stagingWe examined the relationship between pT staging (classified as pT1, pT2, pT3, and pT4) and serum LR11 levels (Table 1). The serum LR11 levels tended to be lower in patients staged pT1, and to rise with increased tumor invasion degree; however, no significant differences were found (Figure 2). Relationship between serum LR11 levels and pN stagingRegarding pN, the mean ± standard deviation values of serum LR11 in each group characterized as pN0, pN1, pN2 and pN3 showed no significant differences (Figure 3).Relationship between serum LR11 levels and vascular invasionWe examined serum LR11 by classifying patients according to the degree of lymphatic invasion into ly0, ly1, ly2, and ly3 (Figure 4) and according to MethodsResults