MIB-1 immunohistometry of follicular adenoma and follicular carcinoma of the thyroid gland.

Abstract To analyze cellular proliferative activity, MIB-1 immunopositivity of normal tissue (n = 20), follicular adenoma (n = 30) and follicular carcinoma (n = 32) of the thyroid gland was analyzed by means of immunohistometry. Immunohistochemical reactions were performed on 3-micron sections from routinely formalin fixed and paraffin embedded surgical specimens using an indirect peroxidase method. The rate of immunostained cells was determined using the CM-2 TV image analysis system (Hund, Wetzlar, Federal Republic of Germany). Forty viewing fields (1.94 mm2) were measured with 20:1 objective magnification. An average of 5,965 cells were assessed in each case. Mean MIB-1 immunopositivity was higher in follicular carcinoma (average, 2.30%) and follicular adenoma (0.58%) than in normal thyroid tissue (0.14%). The distribution of single values differed significantly between groups (P