Abstract: To investigate the autoimmune mechanisms of schizophrenia, we explored the relationship between schizophrenia and cancer using gene expression data of peripheral blood mononuclear cells from GSE27383 datasets. Gene screening and enrichment analysis using Gene Set Enrichment Analysis were applied to identify possible connections between schizophrenia and cancer. Real-time PCR (quantitative PCR), Western blotting and immunohistochemistry were performed on the brain tissue from both schizophrenia patients and normal controls. The genes for IL-8 , as well as PTGS2 , TPR , JUN , CXCL1 , CXCL3 , CXCL5  and PARD3  were highly expressed in schizophrenia patients. Cancer and chemokine signaling pathways were enriched in the schizophrenic group, related to the high expression of IL-8 . Increased expression of IL-8 was further confirmed by quantitative PCR, Western blotting and immunohistochemistry results. Our results suggest that IL-8  may participate specifically in the pathophysiological changes that occur in schizophrenia. Additionally, our findings provide novel evidence supporting the autoimmune hypothesis of schizophrenia.
Keywords: bioinformatics, multiple primary cancers, autoimmune disease, cancer pathway, GSEA