Abstract: Background and purpose: Colorectal cancer (CRC) is the third most common cancer in the world. Recently, it is suggested that interleukin (IL)-35 and/or IL-37 are associated with CRC, but the precise underlying mechanism has not been fully explored. The aim of this study was to explore the correlation between IL-35 or IL-37 and clinicopathology of CRC, and to determine whether IL-35 or IL-37 could be used as prognosis biomarker for CRC patients. Methods: Tissue array was generated from both CRC (n=191) and the matched non-cancer tissues (n=141) from the same patient’s adjacent tissues from 2013 to 2017 in Department of Pathology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine. Quantitative analysis for IL-35 and IL-37 was performed on these immunohistochemically (IHC) labelled tissues using Image-Pro Plus software, for comparison between cancer and non-cancer tissues. We investigated the correlation between IL-35/IL-37 in the CRC tissues and pathology, as well as prognosis. Results: The expression of IL-35 was decreased by 50% in CRC tissues compared with non-cancer tissues (P<0.000 1). In contrast, the expression of IL-37 was increased by 40% in CRC tissues compared with non-cancer tissues (P=0.012). Furthermore, the expression of IL-35, but not IL-37, in cancer tissues (HR=0.39, 95% CI: 0.16-0.97, P=0.04) was an independent predictor of postoperative survival in CRC patients, using the multivariate survival analysis. Conclusion: The expression of IL-35 or IL-37 may be involved in the development of CRC. The expression of IL-35 is believed to be an independent predictor of postoperative survival in CRC patients. The precise mechanism of IL-35 and IL-37 in the development of CRC in vivo will be determined in future.

Key words: Colorectal Cancer, Interleukin-35, Interleukin-37, Prognosis, Multivariate analysis