Evaluation and Validation of Tumor-Associated Antigen p53 as Biomarker in Liver and Lung Cancer

During cellular stress, p53 can slow down cell cycle progression, allowing DNA to either be repaired or lead to cell apoptosis.  In human cancer, the most common changes in p53 are missense point mutations within the coding region of the p53 gene.  These point mutations can alter a protein’s functions and increase their stability.  Antibodies to p53 have been found in many types of human cancer. The aim of this project is to evaluate and validate whether p53 and its antibody can be used as a biomarker for liver and lung cancer. First, expression and induction of p53 was done. Purification of p53 was then performed using nickel column chromatography.   A SDS-PAGE gel was then used to test the quality of the purified p53. Lastly, enzyme-linked immunosorbent assay (ELISA) and Western blotting were used in order to test the reactivity of p53 in sera from patients with lung cancer and liver cancer, as well as sera from normal individuals.  ELISA results showed that the frequency of antibodies to p53 in lung cancer and HCC were 28% (44/157) and 14% (12/86), respectively, which were significantly different compared to normal individuals. The positive ELISA results were verified by Western Blot.  Our preliminary results indicate that the antibody to p53 can be used as a biomarker for both liver and lung cancer.  Thus, p53 and its antibody can possibly be used in early detection of both liver and lung cancer.