Abstract: Objective To investigate the clinical significance of mitochondrial DNA (mtDNA) content in peripheral blood mononuclear cells (PBMC) in the diagnosis of primary liver cancer (PLC).Methods The whole blood samples, clinical data and laboratory indexes of 250 PLC patients (test group) and 48 healthy individuals (control group) were collected. The PBMC were isolated by FicollHypaque centrifugation. The gene content of NADH dehydrogenase subunit 1 (ND1) in mitochondria was detected by quantitative real-time polymerase chain reaction, and the β-globin of nuclear genome was amplified simultaneously as the internal reference. The mtDNA content in PBMC were compared between 2 groups, and the diagnostic efficacy of mtDNA, alpha-fetoprotein (AFP) and mtDNA combined with AFP were analyzed by receiver operating characteristic curves.Results The mtDNA content in PBMC of liver cancer patients (90.51) was significantly lower than that of control group (456.67). The area under the curve (AUC) (0.884) and sensitivity (75.20%) of mtDNA were slightly higher than those of AFP (0.866, 71.70%). The AUC of mtDNA combined with AFP in the diagnosis of PLC was 0.957, significantly higher than that of mtDNA and AFP alone. And the sensitivity increased to 84.91% when the 2 markers were combined.Conclusion The content of mtDNA in PBMC can be used as an auxiliary indicator in the diagnosis of liver cancer.

Key words: Primary liver cancer, Peripheral blood mononuclear cell, Mitochondrial DNA