Proliferative activity of benign and neoplastic endocervical epithelium and correlation with HPV DNA detection

Recent studies have indicated that the use of the MIB-1 immunostaining may be useful in distinguishing endocervical neoplasia from benign nonneoplastic lesions. We sought to investigate this finding further with a specific emphasis on the common benign processes that may result in a nonspecific increase of MIB-1 staining. In this study we quantified the MIB-1 immunostaining in the mucinous endocervical epithelium (n=45) and in tubal metaplasia (n=28) during the proliferative and secretory phases (hormonal influence), in the mucinous endocervical epithelium in cases of cervicitis (inflammation) (n=10), in cases with a history of a recent biopsy (regeneration) (n=15), endocervical polyps (benign growth) (n=8), in the endocervical glands adjacent to a squamous intraepithelial lesion (human papilloma virus [HPV] infection) (n=63), and in in situ and invasive cervical adenocarcinomas (n=30). All cases with increased MIB-1 staining were subsequently tested for the presence of HPV DNA. The range of MIB-1 staining in the benign endocervical epithelium was from 0% to 48% and in the neoplastic epithelium from 25% to 84%. MIB-1 staining below 10% always reflected a benign process and MIB-1 staining higher than 50% was always associated with a neoplasia. Rare benign cases (tubal metaplasia during the proliferative phase, glands adjacent to squamous intraepithelial lesions, and cases with a history of a recent biopsy) had increased MIB-1 index, which overlapped with the neoplastic cases. In conclusion, MIB-1 is a useful marker of endocervical neoplasia, although in rare cases an overlap between benign and neoplastic cases may exist.