Prognostic Value and Immunological Role of the Interleukin 24 Gene in Pan-Cancer Using the Kaplan-Meier Plotter and GEPIA by Genomic Data Commons and R Programming Software

There exists an exclusive cytokine and tumor suppressor gene, which is called Interleukin 24 (IL-24), in interleukin 10 (IL-10) family with antitumor and immune-activating properties. However, pan-cancer analysis of IL-24 for identifying survival prognosis and tumor immune infiltration level remains lacking. This study utilized multiple online data analysis approaches, including TIMER, Oncomine, GEPIA and the Kaplan-Meier Plotter, for analyzing the differences in expression level, survival and tumor immune infiltration of IL-24 from a pan-cancer perspective. The expression dissection expounded IL-24 was under conveyed inside brain and prostate cancers, etc., but overexpressed in breast, colorectal and gastric cancers, etc. Also, the survival analysis indicated that IL-24 expression was positively linked to subsisting inside breast carcinoma, sarcoma, and lung adenocarcinoma, and negatively correlated with stomach adenocarcinoma, kidney renal papillary cell carcinoma, and uveal melanoma. Then, we selected breast cancer and stomach adenocarcinoma as representative cancers for further study and investigation.We found that IL-24 is obviously associated with the immune cellular infiltration inside breast tumor and stomach adenocarcinoma, where IL-24 is significantly linked to the CD4+ T cell and CD8+ T cell infiltration inside breast cancer. As to the subtypes of breast cancer, IL-24 is evidently linked to CD8+ T cells, B cells and CD4+ T cells in BRCA-basal and BRCA-luminal subtypes. Furthermore, we discovered that IL-24 expression is negatively associated with the tumor mutation burden (TMB) and that there is a higher survival rate with IL-24 overexpression in breast cancer patients with a low TMB. This finding suggests that IL-24 can be a substantial biomarker to predict prognostic value and evaluation of infiltrated immune constituents in several cancers.