A Pan-cancer Analysis of the Prognostic and Immunological Role of PPP1R14A
Authors: Lu JiaJie , Huang Rihong , Wang Haojian , Peng Yuecheng , Fan Yongyang , Feng Zejia , Zeng Zhaorong , Ji Yunxiang , Wang Yezhong , Wang Zhaotao 
Published: September 2021

Abstract
BackgroundDespite emerging evidence revealed the remarkable roles of Protein Phosphatase 1 Regulatory Inhibitor Subunit 14A (PPP1R14A) in cancer tumorigenesis and progression, no pan-cancer analysis is available. Our research, for the first time, comprehensively investigated the potential carcinogenic mechanism of PPP1R14A across 33 tumors using bioinformatic techniques. MethodsTCGA datasets and the CPTAC datasets embedded in UALCAN were first applied to study the differential expression of PPP1R14A in various cancer types at the transcription and protein levels, respectively. Besides, we also conducted relevant prognostic survival analysis and used the GEPIA2 database to explore the association between PPP1R14A expression and pathological stages. In addition, cBioPortal and UALCAN databases were employed to analyze the genetic alterations and post-transcriptional phosphorylation of PPP1R14A. Then based on TCGA, we analyzed the relationship between PPP1R14A and immune infiltration, the correlation with tumor mutational burden (TMB), microsatellite instability (MSI) and immune checkpoint molecules (ICMs), and whether it is expected to be a predictive indicator in cancer patients, which was achieved by receiver operating characteristic (ROC) curve. Finally, STRING, GEPIE2 and TIMER2.0 databased were used to explore the potential mechanism of PPP1R14A in cancer and find molecules that have potential close interactions with PPP1R14A.ResultsPPP1R14A is down-expressed in major malignancies and there is a significant correlation between the PPP1R14A expression and the prognosis of patients. Pan-cancer survival analysis indicated that the high expression of PPP1R14A in most cases was associated with poor overall survival (OS), disease-specific survival (DSS), and progress-free interval (PFI) across patients with various malignant tumors, containing adrenocortical carcinoma (ACC), bladder urothelial carcinoma (BLCA). The results of ROC analysis subsequently exhibited that the molecule has a high reference significance in diagnosing a variety of cancers. Besides, we detected that the frequency of PPP1R14A genetic changes including genetic mutations and copy number alterations (CNAs) in uterine carcinosarcoma reached 16.07%, and these alterations brought misfortune to the survival and prognosis of cancer patients. In addition, the methylation within the promoter region of PPP1R14A DNA was enhanced in a majority of cancers. Downregulated phosphorylation levels of phosphorylation sites including S26, T38, etc. in most cases took place in several tumors, such as breast cancer, colon cancer, etc. PPP1R14A remarkably correlated with the levels of infiltrating cells and immune checkpoint genes. ConclusionsOur research summarized and analyzed the carcinogenic effect of PPP1R14A in different tumors comprehensively and provided a theoretical basis for promising therapeutic and immunotherapy strategies.