Interleukin-18 Is a Prognostic Marker and Plays a Tumor Suppressive Role in Colon Cancer
Xiaodong Feng, Zhijun Zhang, Peng Sun, Guanghui Song, Lu Wang, Zhenqing Sun, Ning Yuan, Qing Wang, Limin Lun
Abstract
Interleukin-18 (IL-18) belongs to the IL-1 family and is an essential proinflammatory and immune regulatory cytokine. The present study was designed to investigate the expression and function of IL-18 in colon cancer. In clinical analyses, mRNA and protein expressions of IL-18 were decreased in tissues of colon cancer patients. This decreased expression of IL-18 was significantly correlated with the tumor size ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>P</a:mi> <a:mo>=</a:mo> <a:mn>0.001</a:mn> </a:math> ) and American Joint Committee on Cancer (AJCC) stage ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>P</c:mi> <c:mo>=</c:mo> <c:mn>0.013</c:mn> </c:math> ). Patients with IL-18-positive tumors had a better survival rate than patients with IL-18-negative tumors. Moreover, upregulation of IL-18 inhibited colon cancer cell proliferation. Our data suggest that the decreased expression of IL-18 in colon cancer was associated with prognosis and tumor proliferation. IL-18 may be considered a novel tumor suppressor and a potential therapeutic target for colon cancer patients.