Identification of immune subtypes and prognosis of hepatocellular carcinoma based on immune checkpoint gene expression profile.

The significant response of immunotherapy is currently limited to a small number of patients, which has a high degree of selectivity. Therefore, distinguishing the immune subtypes of the tumor is necessary for patients who may benefit from immune checkpoint therapy. Clinical data and RNA expression data from The Cancer Genome Atlas (TCGA) and GENE EXPRESSION OMNIBUS (GEO) databases were used to study the relationship of immune regulatory pathways with immune subtypes, and the effects on the prognosis of hepatocellular carcinoma (HCC) patients. Eight immune checkpoint coding genes (ICGs) were obtained that closely related to prognosis. Adaptive immune pathway genes (CD8A, CD68, GZMB, and NOS2) show significant positive correlation with most of ICGs. Therefore, adaptive immune pathway genes may play a certain regulatory role in the expression of ICGs. Among the four immune subtypes, the group with low expression level of PD-L1, IDO1 and CTLA4, and high expression of CD8A had showed the best prognosis. The prognosis was the worst in the group with low expression of PD-L1, IDO1 and CTLA4, and showed low expression of CD8A. This research proposed a method to analyze the gene expression profile of immune checkpoints. The present method can be applied to identify the relationship between immune subtype of HCC and the prognosis, providing basis for gene immunotherapy in HCC patients.