Purpose: Transforming growth factor (TGF)-beta regulates cell growth inhibition. When tumor cells lose their sensitivity to TGF-beta growth inhibition, the excess TGF-beta that results may act on tumor cells to facilitate tumor development. Previously, we have shown that an elevated systemic TGF-beta 1 level is not related to tumor progression in esophageal cancer (Y. Fukai et al., Int J Cancer 2003;104:161-6). We considered that systemic inflammation or chronic disease, in addition to the tumor, may influence the plasma TGF-beta level. Therefore, we examined the hypothesis that the plasma TGF-beta level measured from the azygos vein would independently predict tumor progression and prognosis in patients with esophageal cancer.
Experimental design: Fifty-seven plasma samples were obtained intraoperatively from the azygos vein in patients with esophageal cancer. ELISA was used to quantify the plasma TGF-beta 1 levels, which were correlated with pathological features and patient survival.
Results: The mean plasma TGF-beta 1 level measured from the azygos vein of esophageal cancer patients was 5.09 +/- 0.48 ng/ml (mean +/- SE). The survival rates of patients with a high TGF-beta 1 level (defined as a level above the 4.6 ng/ml level of normal controls) in the azygos vein were significantly lower than those of patients with a low TGF-beta 1 level (P = 0.0317). Moreover, the TGF-beta 1 level in the azygos vein was an independent prognostic factor for overall survival (P = 0.0474).
Conclusions: The level of plasma TGF-beta 1 measured from the azygos vein is an independent predictor in patients with esophageal cancer and may reflect tumor progression more specifically because the azygos vein is responsible for venous return from the esophagus.