Estimation of p53 Antibodies in Malignant Effusions

Abstract

Objective: To detect the presence of antibodies against p53 protein in the sera and cytologically positive malignant effusions. Design: Cross- sectional study. Place and Duration of study: Department of Pathology, Postgraduate Medical Institute. Lahore from March 1997 to November 1999. Patients and Methods: Forty cancer patients were selected with different types of malignancies and having cytologically positive effusions. Both sera and respective effusion fluid were collected and stored at -200 C. Anti-p35 ELISA was then carried out by using commercially available ELISA kit. according: to the manufacturer's instructions. A positive p53 antibody level corresponded to the presence of antibodies against mutant p53 protein produced as a result of a mutation of p53 gene in the said cancer. Results: Positivity for anti-p53 antibodies was observed in 27 out of 40 era (67.5%) and in 19 out of 40 effusions (47.5%) of patients with different types of cancers. The comparison revealed significant difference with a p value of < 0.05. Out of these, 18 subjects had positive anti-p53 antibodies in both the sera and in respective effusion fluids, yielding an overall sensitivity of 66.65 and specificity of 92.3%. Conclusion: The present study demonstrates the usefulness of anti-p53 antibody estimation both in the serum and in effusions. As a marker of neoplasia and as an adjunct to conventional diagnostic cytopathological techniques especially in those tumours in which p53 gene mutations occur.