Abstract
INTRODUCTION: Interleukin (IL)-28, a type III interferon related to the IL-10 family, shares multiple structural and functional characteristics with IL-22, another member of the IL-10 cytokine family. Previous research identified IL-22 as a downstream effector of IL-23 in colorectal tumorigenesis. However, data on IL-28 expression in colorectal cancer (CRC) and its relation to clinicopathological features, prognosis, and IL-23 expression remain limited. METHODS: IL-23 and IL-28 immunohistochemical reactivity was evaluated in 75 specimens of colorectal mucinous adenocarcinoma (MA) and 75 specimens of non-mucinous adenocarcinoma (NMA) using the high-density manual tissue microarray method. Clinicopathological features and survival data were statistically analyzed. RESULTS: MA exhibited higher IL-28 and IL-23 expression than NMA; however, this was statistically significant only for IL-23. IL-23 and IL-28 positivity rates showed a highly significant interrelation in MA only. Within the NMA group, no significant association was observed between IL-23 or IL-28 expression and clinicopathological features or survival. In the MA group, high IL-23 expression was significantly associated with positive lymphovascular invasion, advanced pathological tumor (pT) stage, late TNM stage, and decreased disease-free survival and overall survival. High IL-28 expression was significantly associated with advanced pT stage, lymph node spread, advanced TNM stage, and decreased disease-free survival and overall survival. CONCLUSION: For the first time, the expression of IL-23 and IL-28 has shown a highly significant interrelation in MA patients, suggesting a possible interplay between them. High IL-23 and IL-28 expressions may have adverse prognostic effects on survival in MA. Molecular studies are necessary to further investigate the interaction between IL-23 and IL-28 in CRC.