ISSN:
1524-4741
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: Biomarkers are increasingly important in the analysis of a wide variety of neoplastic processes including breast cancer. While p53, p185erbB-2, and epidermal growth factor (EGF) receptor are considered to be well-characterized biomarkers in ductal carcinoma in situ (DCIS) and in invasive adenocarcinoma of the breast, the characterization of these biomarkers by immunohistochemistry may be problematic. ErbB-2 protein (p185erbB-2) must be identified clearly on cytoplasmic membranes for breast cancers to be classified as overexpressing p185erbB-2 while ignoring cytoplasmic expression. For p53, nuclear staining and the percent of positive cells are considered, but rules for “cut-offs” of numbers of positive cells for a case to be classified as positive are not defined. Problems with immunodetection of biomarkers using immunohistochemical techniques can be subdivided to problems with the antigen, the antibody, fixation-tissue processing, and evaluation-interpretation. For example, the initial methods of fixation and tissue processing can modify both the pattern and intensity of immunohistochemical identification of specific antigens and localization of receptors may change after the receptor-ligand interactions. We have evaluated the effects of fixation both on the immunolocalization and intensity of expression of p53, p185erbB-2 and EGF receptor. We also have studied the patterns of p185erbB-2, p53, and EGF-receptor expression in a series of breast cancers evaluated concomitantly with a group of prostate cancers. Our results confirm that p53 mutations are common in breast cancer and that there is strong expression of p185erbB-2 on the membranes of a subset of breast cancers. The patterns of staining for both p53, p185erbB-2, and EGF-receptor are different in prostate and breast cancers. For example, higher concentrations of primary antibody to p53 protein and to p185erbB-2 are necessary to demonstrate nuclear p53 accumulation or membrane p185erbB-2 expression in prostate cancers than in breast cancers. In contrast, a higher concentration of antibody to the EGF-receptor is necessary to demonstrate EGF-receptor expression in breast cancers than in prostatic adenocarcinoma. Neutral buffered formalin is a poor initial fixative compared with other fixatives for demonstrating p53 accumulation or p185erbB-2 expression. The effect of formalin fixation can be reversed with antigen retrieval methods increasing detection markedly in cells with nuclear p53 accumulation. Antigen retrieval techniques were not effective in increasing immunodetection of p185erbB-2 or EGF-receptor in breast adenocarcinomas.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1524-4741.1995.tb00246.x
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