IMMUNOHISTOCHEMICAL EVALUATION OF P-GLYCOPROTEIN IN HUMAN MALIGNANCIES BY MONOCLONAL-ANTIBODY MC57

P-glycoprotein expression was analyzed on 137 formalin-fixed, paraffin -embedded human tumours by monoclonal antibody (MAb) MC57. This MAb re cognizes an extracellular human specific P-glycoprotein epitope and de fines their multidrug resistance (MDR) phenotype by its binding on cel ls. Immunohistochemistry indicated that this MAb reacted in human cell s and tissues in the same pattern as that found with other MAbs to P-g lycoprotein. However, the present extensive study demonstrated that MA b MC57 is a highly specific reagent for the evaluation of an extracell ular P-glycoprotein epitope preserved after fixation procedures and th at this MAb is available to assess P-glycoprotein expression in routin ely processed human tumour specimens. (C) 1994 Wiley-Liss, Inc.