Correlation of Reduced PTGER3 Expression with Prognosis and Immune Infiltration in Clear Cell Renal Carcinoma

Prostaglandin E2 receptor 3 (PTGER3, EP3) is essential for many malignancies growth and metastasis. The role of PTGER3 in kidney renal clear cell carcinoma (KIRC) was assessed in terms of its prognosis and its association with immune infiltration.

Transcriptomic expression profiles of PTGER3 were acquired from The Cancer Genome Atlas (TCGA) database. Comparative analysis was performed to evaluate the disparity in PTGER3 expression between KIRC and normal tissues. The discriminative potential of PTGER3 as a distinguishing determinant was assessed through receiver operating characteristic (ROC) curves. Prognostic factors were evaluated employing COX regression and logistic models. Furthermore, the impact of PTGER3 on survival was ascertained utilizing the Kaplan-Meier method. A protein-protein interaction (PPI) network was constructed utilizing the STRING database. To investigate the correlation between immune infiltration levels and PTGER3 expression, a single-sample Gene Set Enrichment Analysis (GSEA) method was employed, employing the Gene Set Variation Analysis (GSVA) package and the Tumor Immune Estimation Resource (TIMER) database.

Bioinformatics analysis unveiled a significant downregulation of PTGER3 expression in KIRC tissues compared to paraneoplastic tissues (p < 0.001). Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) experiments demonstrated a reduction in PTGER3 expression in 786-O cells in contrast to paraneoplastic tissues (p < 0.01). The ROC curve, employing PTGER3 as a potential diagnostic biomarker, exhibited a substantial area under the curve (AUC) value of 0.929. According to the Kaplan-Meier survival analysis, reduced PTGER3 expression increased the chance of negative overall survival (OS) (p = 0.019). A PPI network was constructed, elucidating the interaction patterns between PTGER3 and the top 10 co-expressed genes. An examination of gene enrichment and immune infiltration levels found a link between PTGER3 transcription and immune infiltration levels. Notably, high B cell counts and low Mast cell counts were connected to a poor prognosis in KIRC patients.

The expression of PTGER3 was found to be diminished in KIRC in comparison to paracancerous tissue. This observation exhibited a correlation with both prognosis and immune cell infiltration. As a result, our findings suggest that PTGER3 could be considered a promising biomarker to forecast KIRC prognosis and as a possible target for immunotherapy.