p53 overexpression in formalin-fixed, paraffin-embedded tissue detected by immunohistochemistry.

Authors:
  • PJP A Jordan
    P A Jordan
  • MMM B Moore
    M B Moore
  • PHP A Humphrey
    P A Humphrey
  • ABA Berchuck
    A Berchuck
  • MKM F Kohler
    M F Kohler
  • JIJ D Iglehart
    J D Iglehart
  • JMJ R Marks
    J R Marks
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Abstract
Mutation and overexpression of the p53 gene have been noted in a wide range of human cancers and are thought to play a role in malignant transformation. Previously, immunohistochemical detection of p53 has been possible only in fresh-frozen tissues. We examined p53 expression in paraffin-embedded tissues from 50 epithelial ovarian cancers and 25 primary breast cancers with a modified immunohistochemical (IHC) technique developed in this laboratory, using monoclonal antibody (MAb) PAb1801. The 75 cases were selected from a group of patients in whom the expression levels had already been assessed in a fresh-tissue IHC assay. An identical staining reactivity was observed in both formalin-fixed, paraffin-embedded tissue and fresh-frozen tissue in 48 of 50 (96%) epithelial ovarian cancers and in 23 of 25 (92%) primary breast cancers. Immunodetection of p53 in paraffin-embedded tissue blocks will be a useful alternative to the standard fresh-tissue assay and can accurately reflect the level of p53 expression in human tumors.