Objective    To evaluate the clinical significance of serum P53 protein level in the diagnosis of hepatocellular carcinoma (HCC).     Methods    Serum P53 protein levels were determined by enzyme linked immunosorbent assay (ELISA) for 327 HCC patients

91 hepatic cirrhosis (HC) patients and 80 healthy subjects. Immunohistochemical staining (IHC) and Western blotting were performed to detect the expression of P53 protein for 130 HCC patients who received biopsy and operation. Receiver operating characteristic curve (ROC) was used to analyze the concordance of serum P53 protein and alpha fetoprotein (AFP) level.     Results    A significant increase of serum p53 levels was found in HCC patients compared to healthy subjects and HC patients (P0.05). A single band of 53 000 was detected in the corresponding sera by Western blot assay. The elevation of serum P53 protein levels was validated by the results of Western blotting. The coincidence rate of the results by ELISA and IHC was 84.62%. The area under curve (AUC) of P53 protein and AFP was 0.910 and 0.954

respectively (Kappa=0.657

P=0.000)

suggesting no significant difference exists between the two methods.     Conclusion    The elevation of serum P53 protein level reflects the mutation of p53 gene. P53 protein can be regarded as the serum tumor marker and used in the prognosis of HCC and the guidance of clinical therapy.