Interleukin-32 expression and Treg infiltration in esophageal squamous cell carcinoma

Interleukin-32 (IL32) has been newly-identified as a proinflammatory cytokine. In the present study, we aimed to clarify the clinical role of IL32-positive cells in esophageal squamous cell cancer (ESCC) and regulatory T-cell (Treg) infiltration in the stroma. A total of 179 patients with ESCC who underwent surgical resection from 1990 to 2004 were eligible for this study. The expression of IL32 and the degree of stromal infiltration by Tregs were examined simultaneously. The association between each factor and the clinicopathological features was analyzed. Sixty and 74 out of 179 patients with ESCC were regarded as having IL32-positive tumors and many Tregs (high-Treg group), respectively. The IL32-positive and high-Treg groups had significantly deeper tumor invasion than did the IL32-negative and low-Treg groups (p<0.05, for both groups). The multivariate analysis indicated that a combination of IL32 expression and presence of Tregs was one of the poor independent factors (p<0.05). IL32 expression and Treg infiltration in ESCC play an important synergistic role in tumor growth and invasion. The combination of IL32 positivity and degree of infiltration of Treg is a useful prognostic marker in ESCC.