High expression of PPIA associates with poor prognosis and tumor immune infiltration of gastric cancer

Abstract

Background Gastric cancer (GC) is a malignant tumor with high incidence rate and mortality. Due to the lack of effective diagnostic indicators, most patients are diagnosed in late stage and have a poor prognosis. An increasing number of studies have proved that PPIA can play an oncogene role in various cancer types. However, the precise mechanism of PPIA in GC is still unclear. Methods The mRNA levels of PPIA in pan-cancer and the prognostic value of PPIA on GC was evaluated using multiple databases. Additionally, the relationship between PPIA expression and clinical factors in GC was also examined. Moreover, the genetic alteration and DNA methylation analysis was conducted. Furthermore, the upstream regulator miRNA and lncRNA of PPIA were identified. Finally, the relationship between PPIA expression and immune checkpoint expression, immune cell biomarkers, and immune cell infiltration in GC were also performed by TIMER database. Results PPIA was upregulated in most tumor tissues compared to the corresponding normal tissues including GC and PPIA expression had a close relationship with GC patients. However, the abnormal expression of PPIA was not affected by genetic alteration and DNA methylation. We confirmed that PPIA was regulated by upstream ncRNAs and the upstream regulator miRNA and lncRNA of PPIA were identified. Finally, this study revealed that PPIA was negatively correlated with immune checkpoint expression, immune cell biomarkers, and immune cell infiltration in GC. Conclusions lnc01232/miRNA-204-5p/PPIA axis might act as a potential biological pathway in GC and negatively related to immune cell infiltration in GC.