Immunoreactivity of involucrin in cervical condyloma and intraepithelial neoplasia

Ninety-three cervical conization specimens with condyloma or intraepithelial neoplasia were stained by the peroxidase-antiperoxidase technique for involucrin. Diffuse, homogeneous suprabasal staining was observed in the ectocervical squamous mucosa and mature squamous metaplasia. In immature squamous metaplasia, staining was limited to cells with apparent squamous differentiation. Although diffusely reactive in the upper layers of condyloma and cervical intraepithelial neoplasia (CIN) grade I, the stain was uneven in the former and lacking in the parabasal layers of the latter. The staining intensity, distribution, and pattern were more variable in CIN grade II and grade III. With increasing severity, a patchy pattern with a mixture of reactive and nonreactive cells predominated. Although immunoreactivity with involucrin could not distinguish immature squamous metaplasia from neoplasia, the staining patterns in CIN correlated with extent of disease, degree of squamous differentiation, and cellular disorganization.