ObjectiveTo analyze the expression of Lactate dehydrogenase A（LDHA） in both renal cell carcinoma （RCC） tissue and RCC cell lines， and to investigate the impact of LDHA expression on the progression of RCC. MethodsFrom June 2018 to June 2022， totally 52 cases of RCC tissue samples and 49 cases of para-cancerous tissue samples were collected through surgical procedures from our hospital. LDHA expression was detected using immunohistochemistry （IHC）. The expression levels of LDHA in vitro were also detected in the normal human proximal tubule epithelial cell line HK-2 and renal cell carcinoma cell lines A498， Caki-2， ACHN， and 786-O by using qRT-PCR and Western blot. A recombinant plasmid carrying LDHA-shRNA was constructed and then transfected into 786-O cells to down-regulate the expression of LDHA. Tumor proliferative capacity was monitored using CCK-8 assay， clonal formation assay and EdU assessments. Additionally， cell glycolytic activity was assessed through glucose uptake assay， lactate secretion assay， and ECAR analysis. ResultsIHC analysis revealed significantly higher expression of LDHA in RCC tissue compared to adjacent tissues（P<0.05）. Furthermore， RCC tissues with higher TNM stage exhibited greater expression of LDHA than those with lower TNM stage （P<0.05）. The results of qRT-PCR and Western blot demonstrated that the expression of LDHA in each RCC cell line was significantly higher than that in HK-2（P<0.05）. After blocking the expression of LDHA in 786-O， there was a significant down-regulation of cell proliferation and glycolysis capacity （P<0.05）. ConclusionsThe expression of LDHA in RCC tissue and RCC cell lines is significantly overexpressed compared with normal one， particularly in those with higher TNM stage. Knockdown of the expression of LDHA significantly suppresses cell proliferation and aerobic glycolysis capacity in 786-O.