Immunoreactivity of new antibodies anti-p53 and anti-MDM-2 in paraffin embedded tissue samples

Detection of various epitopes of the p53 and MDM-2 proteins, using new antibodies was performed on formalin-fixed and paraffin-embedded tissue samples from breast cancer and compared with results obtained using well-characterized antibodies. The results show that the distribution of positive nuclei and intensity of staining varies significantly depending on the antibody used, as well as on the microwaving procedure. Antibodies DO-14, DO-13 and SMP-14 have very good characteristics and are available for immunohistochemical analysis of p53 and MDM-2. Our results indicate, that immunohistochemical expression of p53 and MDM-2 is a not stable and unitary phenomenon and from this point of view a single antibody is not sufficient for its determination. Since, characteristics of p53 and MDM-2 molecules can vary from one sample to the next, panel antibodies capable of determining a wide range of wide type and mutant conformations must be used.