Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody .p53 is a nuclear phosphoprotein encoded by the TP53 gene located on chromosome 17p13, which in turn encodes several isoforms of the p53 protein. p53 is a tumour-suppressor protein which regulates the genomic stability and binds to the cell division-stimulating protein cdk2.The overexpression of p53 is associated with different neoplastic and preneoplastic lesions. The detection of p53 by immunohistochemistry can be useful to differentiate between dysplastic or neoplastic changes usually positive for p53 and reactive changes negative for p53.