p53 determination in gynecological carcinomas: immunohistochemistry compared to luminometric immunoassay (LIA)

In gynecological carcinomas p53 overexpression has been associated with an aggressive tumor type and shorter overall survival. We compared p53 values analysed by a new quantitative luminometric immunoassay (LIA) applicable on tumor cytosol immunohistochemistry (IH). In 83 breast and 43 ovarian cancers p53 was analysed by LIA and IH (Byk-Sangtec, FRG) and by IH using monoclonal antibodies (MOAB/BP53-Bio Genex, FRG). In breast cancer 32 cases (39%) were immunohistochemically (IH) positive. LIA values ranged from 0.01 to 101 ng/mg protein (p), median (IH negative cases) = 0.208 and median (IH positives) = 0.857 ng/mg p. Using a cut off < 0.2 ng/mg p for a very low expression only 11% (3/27) were IH positive and > 0.8 for very high expression only 16% (3/20) were IH negative. In ovarian cancer values ranged from from 0.01 to 66.1 mg/mg p. 48.8% (21/43) were IH positive, median (IH negatives) = 0.234 and median (IH positives) = 1.43 ng/mg p. At a cut off < 0.2 ng/mg p 25% (3/12) were IH positive and at a cut off > 0.8 ng/mg p only 14% (2/14) were IH negative.

The quantitative LIA determination of p53 in cytosols of gynecological carcinomas shows a good correlation to immunohistochemistry in cases of very high and very low expression.