Sperm-Associated Antigen 9 Assumes Signifying Capacity in Hepatocellular Carcinoma Diagnosis

Abstract Background: Sperm-associated antigen 9 (SPAG9) has been proposed as a novel biomarker for early diagnosis of human tumors. This study was aimed to assess the clinical value of serum SPAG9 for HCC diagnosis.Methods: Serum SPAG9 was measured by quantitative real-time ploymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Chi-square test was applied to evaluate the association between serum SPAG9 mRNA level and clinical characteristics. The diagnostic accuracy of the serum SPAG9 mRNA was assessed using receiver operating characteristic (ROC) curve.Results: Serum SPAG9 level was significantly higher in HCC patients than that in healthy controls at both mRNA and protein levels (P<0.01 for all). Furthermore, serum SPAG9 mRNA level was positively correlated with TNM stage (P=0.047), tumor size (P=0.044), and lymph node metastasis (P=0.014). The area under the curve (AUC) of the ROC curve was 0.794, with a sensitivity of 71.4%, a specificity of 80.4%, suggesting the high diagnostic accuracy of serum SPAG9 mRNA for HCC. The cutoff value was 1.030.Conclusions: Serum SPAG9 is significantly increased in HCC, and positively correlated with aggressive clinical characteristics. SPAG9 may serve as a diagnostic biomarker for HCC.