OBJECTIVETo assess serum levels of endogenous endostatin in patients with clear cell renal cell carcinoma (CCRCC) and to determine the relationship of these levels to tumor stage, grade.

METHODSFrom March 2004 to October 2008, preoperative serum were obtained from 138 consecutive patients with CCRCC (73 patients in T1, 39 patients in T2, 20 patients in T3, and 6 patients in T4) and 40 healthy controls. Serum levels of endostatin were measured by sandwich-ELISA. Associations between circulating endostatin levels and clinicopathologic factors and clinical outcome were determined.

RESULTSEndostatin levels did not differ significantly between the patients with CCRCC (93.1 microg/L) and healthy controls (78.9 microg/L, P > 0.05). Serum levels of endostatin were significantly higher in the T2-4 CCRCC patients (107.2 microg/L) than those of the T1 patients (80.4 microg/L, P < 0.01). No significant difference was found in the endostatin levels among the T2-4 patients, or between healthy controls and the T1 patients. The serum endostatin concentration was significantly higher in the metastasis group (118.4 microg/L) than in the no metastasis group (89.5 microg/L, P < 0.05), but there was no significant difference between patients with distant metastasis group (122.0 microg/L) and lymph nodes metastasis (110.0 microg/L, P > 0.05). Patients with G3-4 tumors had significantly higher endostatin levels (111.8 microg/L) than those of patients with G1 (80.4 microg/L) and G2 tumors (86.2 microg/L, P < 0.01), but endostatin levels did not differ significantly between the two groups (P > 0.05).

CONCLUSIONPreoperative serum levels of endostatin elevated in patients with CCRCC and associated with higher stage and grade.