title: Ki-67 labeling index as an adjunct in the diagnosis of serous tubal intraepithelial carcinoma.
abstract: There is mounting evidence that serous tubal intraepithelial carcinoma (STIC) may be the immediate precursor of ovarian high-grade serous carcinoma (HGSC) but the criteria for its diagnosis are not well established as highlighted in a recent study showing that interobserver reproducibility, even among expert gynecologic pathologists, was moderate at best. Given the clinical significance of a diagnosis of STIC in a patient who has no other evidence of ovarian carcinoma, this is a serious issue that we felt needed to be addressed. Although it is not clear, at this time, whether such a patient should or should not be treated, the importance of an accurate and reproducible diagnosis of precursors of ovarian carcinoma cannot be underestimated. We hypothesized that an elevated Ki-67 labeling index may aid the diagnosis of STIC. Accordingly, we compared the Ki-67 index of STIC and HGSC to normal fallopian tube epithelium (FTE) in the same patients and to a control group of patients without carcinoma, matched for age. A total of 41 STICs were analyzed, of which 35 were associated with a concurrent HGSC. In FTE, immunoreactivity for Ki-67 was restricted to a few scattered cells (mean 2.0%). No statistically significant difference was found between patients with and without HGSC (P>0.05). However, both STICs and HGSC had significantly higher Ki-67 indices than normal FTE (P<0.0001). STICs uniformly had an elevated Ki-67 labeling index that ranged from 11.7% to 71.1% (average 35.6%). There was no correlation of the Ki-67 labeling index in the STICs and the associated HGSC, as the labeling index was lower in STIC in 18/35 (51.4%) whereas it was higher in 17/35 (48.6%) (P=0.86). In conclusion, the findings in this study indicate that compared with FTE, STICs have a significantly higher Ki-67 index similar to HGSC. Accordingly, the Ki-67 index can aid the diagnosis of intraepithelial tubal proliferations suspicious for STIC. Therefore, we propose that a Ki-67 index of 10% is a useful diagnostic tool to distinguish STICs from normal FTE.
authors: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
authors: Elisabetta
authors: E
authors: Kuhn
authors: Robert J
authors: RJ
authors: Kurman
authors: Ann Smith
authors: AS
authors: Sehdev
authors: Ie-Ming
authors: IeM
authors: Shih
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077216:Carcinoma, Ovarian Epithelial; D018284:Cystadenocarcinoma, Serous / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D018095:Germ-Line Mutation; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000175:diagnosis / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000473:pathology*
chemical_list: D019394:Ki-67 Antigen