Pan-Cancer Analysis of Cyclic Nucleotide Phosphodiesterases (PDEs) Expression, Variation, and Prognostic Significance.

Dysregulation in the production of cyclic nucleotides and the upregulation of cyclic nucleotide phosphodiesterases (PDEs) are implicated in many tumor pathologies. Therefore, a comprehensive investigation of PDEs and their dysfunction across different cancers is necessary. In this study, we conducted an in-depth analysis of the genomic expression and variation profiles of PDEs across multiple cancer types. We found that PDE6C, PDE6D, PDE6H, and PDE7A were significantly upregulated in nearly all types of cancer, whereas PDE2A was downregulated in 15 cancer types. Our results demonstrated that somatic copy number alterations (SCNAs) and promoter DNA methylation in pan-cancer samples were heterogeneous and may regulate the expression of PDEs in tumors. We further observed that the expression of PDEs predominantly influences the prognosis of solid tumors. Five differentially expressed PDEs (PDE5A, PDE6D, PDE8A, PDE8B, and PDE9A) were identified as independent prognostic factors for patients with pan-cancer in both the training and testing cohorts. To our knowledge, this is the first study to construct a PDE signature in pan-cancer and to highlight the pivotal role of PDE4D in LIHC (liver hepatocellular carcinoma).