Research on the oncogenic role of the house-keeping gene GAPDH in human tumors

BACKGROUND: As an internal reference gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays an important role in glycolysis. While increasing evidence suggests that GAPDH plays a crucial role in tumorigenesis of some cancers, no systematic analysis of GAPDH has been conducted. Here, we sought to analyze the expression of GAPDH and its oncogenic processes in pan-cancer. METHODS: GAPDH was investigated in The Cancer Genome Atlas (TCGA) tumor types using several bioinformatic tools including Tumor IMmune Estimation Resource (TIMER), Gene Expression Profiling Interactive Analysis (GEPIA), University of ALabama at Birmingham CANcer (UALCAN), cBio Cancer Genomics Portal (cBioPortal), and Search Tool for Recurring Instances of Neighbouring Genes (STRING) for the expression and relationships with prognosis and immune infiltration separately. RESULTS: Through our analysis, we measured the higher expression of GAPDH across the majority of TCGA tumors. GAPDH overexpression predicts poor survival in patients with tumors expressing a high level of GAPDH. Moreover, the genetic changes in GAPDH contributed to an increased mRNA expression. Additionally, GAPDH expression was negatively correlated with immune infiltration involving cancer-associated fibroblasts, neutrophil cell and endothelial. CONCLUSIONS: The house-keeping gene GAPDH might be a promising biomarker for pan-cancer prognosis. And GAPDH is not suitable as an internal reference gene for most cancer research, whether RNA or protein analyses.