Programmed death 1, ligand 1 and 2 correlated genes and their association with mutation, immune infiltration and clinical outcomes of hepatocellular carcinoma

BACKGROUND The exact regulation network of programmed death 1(PD-1), programmed death ligand 1(PD-L1), and programmed death ligand 2(PD-L2) signaling in immune escape is largely unknown. We aimed to describe the gene expression profiles related to PD-1 as well as its ligands PD-L1 and PD-L2, thus deciphering their possible biological processes in hepatocellular carcinoma(HCC).AIM To find the possible mechanism of function of PD-1, PD-L1, and PD-L2 in HCC.METHODS Based on the expression data of HCC from The Cancer Genome Atlas, the PD-1/PD-L1/PD-L2 related genes were screened by weighted correlation network analysis method and the biological processes of certain genes were enriched. Relation of PD1/PD-L1/PD-L2 with immune infiltration and checkpoints was investigated by co-expression analysis. The roles of PD-1/PD-L1/PD-L2 in determination of clinical outcome were also analyzed.RESULTS Mutations of calcium voltage-gated channel subunit alpha1 E, catenin beta 1, ryanodine receptor 2, tumor suppressor protein p53, and Titin altered PD-1/PDL1/PD-L2 expression profiles in HCC. PD-1, PD-L1, and PD-L2 related genes were mainly enriched in biological procedures of T cell activation, cell adhesion, and other important lymphocyte effects. In addition, PD-1/PD-L1/PD-L2 was related with immune infiltration of CD8 T cells, cytotoxic lymphocytes,fibroblasts, and myeloid dendritic cells. Immune checkpoints of CTLA4, CD27, CD80, CD86, and CD28 were significantly related to the PD-1/PD-L1/PD-L2 axis. Clinically, PD-1 and PD-L2 expression was correlated with recurrence(P = 0.005 for both), but there was no significant correlation between their expression and HCC patient survival.CONCLUSION Mutations of key genes influence PD-1, PD-L1, and PD-L2 expression. PD-1, PDL1, and PD-L2 related genes participate in T cell activation, cell adhesion, and other important lymphocyte effects. The finding that PD-1/PD-L1/PD-L2 is related to immune infiltration and other immune checkpoints would expand our understanding of promising anti-PD-1 immunotherapy.

Declining diagnostic accuracy of non-invasive fibrosis tests is associated with elevated alanine aminotransferase in chronic hepatitis B

AIM To explore the effect of alanine aminotransferase(ALT) on the performance of non-invasive fibrosis tests in chronic hepatitis B(CHB) patients. METHODS A total of 599 treatment-naive and biopsy-proven CHB patients were included in the study. The cohort was divided into the following three groups: Normal ALT(ALT ≤ 40), slightly elevated ALT(40 < ALT ≤ 80) and elevated ALT(ALT > 80). The diagnostic performance of five common non-invasive fibrosis tests for liver fibrosis(stages S2-4), including the aspartate aminotransferase(AST)-to-platelet(PLT) ratio index(APRI), fibrosis index based on 4 factors(FIB-4), King's score, Forns index and gamma-glutamyl transpeptidase(GGT)-to-PLT ratio(GPR), were evaluated for each group. RESULTS Higher ALT levels were associated with higher non-invasive fibrosis test scores. Patients with the same fibrosis stage but higher ALT levels showed higher noninvasive test scores. The areas under the receiver operating characteristics curves(AUROCs) of the noninvasive tests for prediction of ≥ S2 were higher for patients with ALT ≤ 40 U/L(range 0.705-0.755) and 40 < ALT ≤ 80 U/L(range 0.726-0.79) than for patients with ALT > 80 U/L(range 0.604-0.701). The AUROCs for predicting ≥ S3 and S4 were higher in patients with ALT ≤ 40 U/L(range 0.736-0.814 for ≥ S3, 0.79-0.833 for S4) than in patients with 40 < ALT ≤ 80 U/L(range 0.732-0.754 for ≥ S3, range 0.626-0.723 for S4) and ALT > 80 U/L(range 0.7-0.784 for ≥ S3, range 0.662-0.719 for S4). The diagnostic accuracy of the non-invasive tests decreased in a stepwise manner with the increase in ALT.CONCLUSION ALT has a significant effect on the diagnostic performance of non-invasive fibrosis tests. The ALT level should be considered before performing these noninvasive tests.