Ppih, also known as Peptidyl-prolyl isomerase H, is a member of the cyclophilin protein family. It functions as a molecular chaperone and is involved in the splicing of pre-mRNA. It directly interacts with pre-mRNA processing factor 4 (PRPF4) and integrates into the pre-catalytic spliceosome as part of the tri-snRNP subcomplex [5].

In cancer research, Ppih has emerged as a significant biomarker. In Hepatocellular Carcinoma (LIHC), Colon adenocarcinoma (COAD), and Breast cancer (BC), Ppih mRNA and protein levels are markedly elevated, associated with a worse prognosis. Conversely, serum Ppih levels are decreased in patients with these tumors. In LIHC, Ppih knockdown in vitro led to reduced cell viability, proliferation, and invasion while promoting apoptosis, and in vivo it repressed tumor growth and modified the immune microenvironment. In Cholangiocarcinoma (CHOL), overexpression of Ppih mRNA is associated with poor prognosis, and Ppih has strong diagnostic value [1,2,3,4].

In conclusion, Ppih plays a crucial role in pre-mRNA splicing and as a chaperone. In the context of cancer, especially in LIHC, COAD, BC, and CHOL, it shows potential as a predictive biomarker and is involved in tumor progression and immune microenvironment modulation. The study of Ppih using in vitro and in vivo models has provided insights into its role in cancer, which may help in developing new diagnostic and therapeutic strategies.