MIB-1 expression is useful in distinguishing dysplasia from atrophy in elderly women.

Both atrophic and dysplastic cervical squamous epithelia show lack of maturation, nuclear crowding, and increased nuclear/cytoplasmic ratio. Because of these similarities, distinguishing dysplasia from atrophy in cervical biopsies from elderly patients is often problematic. Because dysplasia shows increased proliferation and atrophy has decreased proliferation, the possible utility of MIB-1 in distinguishing dysplasia from atrophy was evaluated. One or more of the following criteria were present in all nine cases with dysplasia and in none of the 17 cases with atrophy: MIB-1 expression in > 20% of cells in the basal one-third of the epithelium, > 5% of cells in the middle one-third of the epithelium, and > 1% of cells in the upper one-third of the epithelium. MIB-1 immunostaining is useful in distinguishing dysplasia from atrophy.