Abstract Background A Cholangiocarcinoma (CCA) is highly aggressive malignancy. It accounts for roughly 3% of all gastrointestinal cancers and 10% of all primary hepatobiliary malignancies. The incidence rate of hepatocellular carcinoma (HCC) has doubled in the past decade, indicating an increasing burden of the disease in Egypt. Apurinic/Apyrimidinic endodeoxyribonuclease 1 (APEX1) is the main endonuclease that participates in the base excision repair mechanism in response to DNA damage, and it is expressed across various human tissues. Dysregulated expression of APEX1 may impair various physiological functions. Objectives The current study aims to assess serum APEX1 levels as diagnostic biomarkers for CCA and HCC in contrast to conventional tumor markers. Subjects and methods The study included 171 subjects, comprising 40 healthy volunteers selected from a blood donation unit, 47 patients with CCA, 40 cases with benign biliary disorders (BBD), and 44 cases with HCC. All research participants had their APEX1 levels assessed using the enzyme-linked immunosorbent Assay (ELISA). Results Results indicate that APEX1 levels exhibited significant variation ( p 0.05, AUC 0.614). Conclusion Serum APEX1 represents a promising diagnostic biomarker for both CCA and HCC, but with less performance than other markers except for differentiating CCA from BBD it showed exhibiting superior specificity to CA 19.9 APEX1 levels in CCA cases are significantly correlated with the number of focal lesions and lymph node metastases; however, they do not effectively distinguish CCA from HCC cases.
El-Shaarawy et al. (Thu,) studied this question.