Expression of B7‐H4 in blood of patients with gastric cancer predicts tumor progression and prognosis

Abstract Background and Objectives B7‐H4 is a novel molecular B7 ligand that plays an important role as a negative regulator of the T cell‐mediated immune response. However, the clinical significance of B7‐H4 expression in gastric cancer remains uncertain. Here, we assessed B7‐H4 expression in blood of patients with gastric cancer to determine whether or not it can predict tumor progression and prognosis. Methods We measured B7‐H4 mRNA expression by quantitative RT‐PCR in five gastric cell lines as well as in blood specimens from 94 patients with gastric cancer and from 22 healthy volunteers. Results Significantly more B7‐H4 mRNA copies were found in gastric cell lines and in blood from patients with gastric cancer than in blood from healthy volunteers ( P < 0.0001 and P < 0.0001, respectively). B7‐H4 expressed in 71 (75.5%) of 94 patients with gastric cancer significantly correlated with depth of tumor invasion, lymph node metastasis, and overall stage ( P = 0.006, P = 0.001, and P < 0.001, respectively). The 5‐year survival rate was significantly lower in patients with than without B7‐H4 expression ( P = 0.04). Conclusions The evaluation of B7‐H4 expression in blood is a useful tool for predicting the progression of gastric cancer and prognosis. J. Surg. Oncol. 2010;102:748–752. © 2010 Wiley‐Liss, Inc.