A Novel Prognostic Biomarker LPAR6 in Hepatocellular Carcinoma via Associating with Immune Infiltrates

Background and Aims: LPAR6 is the most recently determined G protein-coupled receptor of lysophosphatidic acid, and hardly any study has demonstrated the performance of LPAR6 in cancers. We sought to clarify the relationship of LPAR6 to prognosis potential and tumor infiltration immune cells in different cancers. Methods: The expression of LPAR6 and its clinical characteristics were evaluated on various databases. The association between LPAR6 and immune infiltrates of various types of cancer were investigated via TIMER. Results: We determined that higher LPAR6 expression level was associated with a better overall survival. Additionally, high LPAR6 expression level was significantly associated with better disease-specific survival (DSS) in bladder cancer, and better overall survival (OS)/ progression-free survival (PFS)/ distant metastasis-free survival (DMFS)/ relapse-free survival (RFS) in breast cancer and some other types of cancers. Moreover, LPAR6 significantly affects the prognosis of various cancers via The Cancer Genome Atlas (TCGA). Further research exposed that the mRNA level of LPAR6 was positively coordinated with infiltrating levels of devious immune cells in hepatocellular carcinoma. Conclusions: Our results imply that LPAR6 is associated with prognosis potential and immune infiltration levels in liver cancer. Moreover, LPAR6 expression possibly contributes to the activation of CD8+ T, naive T, effector T cells and natural killer cells and inactivates T regulatory cells, decreases T cell exhaustion and regulate T helper cells in liver cancer. These discoveries imply that LPAR6 could be a novel biomarker of prognosis for indicating progno-sis potential and immune-infiltrating level in hepatocellular carcinoma.