show Abstracthide AbstractTo interrogate IL4I1 regulated genes and analyze the role of IL4I1 in the anti-PD-L1 antibody-resistance, a comprehensive gene expression analysis was performed. RNA-sequence analysis revealed that expression of cell differentiation-related genes was increased in the IL4I1-overexpressing cells. Also, anti-PD-L1 antibody-treated IL4I1-overexpressing tumors upregulated immunosuppressive genes, including those related with regulation of cytokine production, negative regulation of immune system process, compared with anti-PD-L1 antibody-treated control (mock) tumors. These differences in gene expression were not observed in the IgG control groups, suggesting that the immunosuppressive gene expression was induced in response to the anti-PD-L1 antibody treatment.