Circulating levels of endostatin in cancer patients

Endostatin is a negative regulator of angiogenesis. We examined plasma endo statin levels (PESLs) in cancer patients and healthy controls. PESLs were d etected by competitive enzyme immunoassay in 147 patients with primary brea st cancer, 44 patients with other histological types of cancer, 26 patients with recurrent breast cancer, 17 patients with benign breast disease and 2 21 healthy controls. PESLs were elevated in those patients with cancer or b enign breast disease, in patients with primary breast cancer, significantly higher PESLs were found in post-menopausal patients than in pre-menopausal patients (p<0.01), although there were no differences in the other clinico pathological characteristics evaluated. PESLs in primary breast cancer pati ents did not change after surgery, but they increased after administration of the adjuvant tamoxifen. When we applied an age-matched cut-off value as a mean of the values for the female controls, we found that node-negative b reast cancer patients with high PESLs had a significantly more favorable re lapse-free survival time than those with low PESLs (p<0.05, log-rank test). Our data demonstrate that PESLs are detectable in healthy controls, and th at cancer patients have elevated PESLs. A larger study is warranted to clar ify the clinical significance of circulating endostatin.