Keratin 17 Is a Prognostic Biomarker in Endocervical Glandular Neoplasia

Objectives: Previous work in our laboratory identified keratin 17 (K17) as a specific and sensitive biomarker for high-grade squamous intraepithelial lesions and cervical squamous cell carcinoma (SCC). K17, however, has not been previously evaluated in endocervical glandular neoplasia. Based on the similar pathogenesis of squamous and glandular lesions of the cervix, we hypothesized that K17 overexpression could also be a diagnostic and/or prognostic biomarker for endocervical neoplasia. Methods: Cases of endocervical adenocarcinoma (n = 90), adenocarcinoma in situ (AIS) (n = 32), benign glandular lesions (n = 36), and normal endocervical mucosa (n = 5) were selected from Stony Brook Medicine and the University of Massachusetts from 2002 to 2013. Immunohistochemical staining for K17 was performed by an indirect immunoperoxidase method and was scored based on the proportion of cells that showed strong (2+) staining. Results: K17 was highly expressed in 21 (65.6%) of 32 AIS and in 75 (83.0%) of 90 adenocarcinoma cases. In adenocarcinomas, K17 staining was detected in a mean of 33.9% of malignant cells. Staining tended to be strongest at the periphery of pseudoglandular groups and at the invasive front of tumors. K17 was not detected in the epithelial cells of benign glandular lesions, but groups of cuboidal cells, residing beneath the epithelial layer of benign glands, were frequently positive for K17, especially in cases of microglandular hyperplasia. High levels of K17 expression were significantly associated with decreased patient survival. Conclusions: K17 is highly expressed in most cases of both invasive adenocarcinoma and in AIS and is a powerful, negative prognostic marker for patient survival.