title: The role of cytokeratin 5/6 as an adjunct diagnostic tool in breast core needle biopsies.
abstract: In this article, the probability of finding malignancy on surgical excision after applying well-defined morphological criteria combined with immunohistochemical evaluation of cytokeratin 5/6 for the diagnosis of atypical ductal hyperplasia on core biopsies is examined. On the basis of morphology alone, the reviewers reclassified the diagnoses of 140 core biopsies as follows: atypical ductal hyperplasia (n = 64), ductal hyperplasia of usual type (n = 44), flat epithelial atypia (n = 11), and miscellaneous benign (n = 21). Cytokeratin 5/6 immunostain was negative in 85.7% of atypical ductal hyperplasia cases and positive in 77.8% of ductal hyperplasia of usual type cases. The probability of predicting malignancy in a surgical specimen following a core biopsy increased from 43.6% to 67.8% (P = .002) by adhering to defined criteria and using cytokeratin 5/6 immunostain. Expertise and adherence to defined criteria are required to establish an accurate diagnosis of atypical ductal hyperplasia. Cytokeratin 5/6 can be a useful adjunct in cases with ductal hyperplasia but not in columnar cell lesions, where it is universally negative.
authors.affiliation: Department of Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada.
authors.forename: Sharon
authors.initials: S
authors.lastname: Nofech-Mozes
authors.forename: Claire
authors.initials: C
authors.lastname: Holloway
authors.forename: Wedad
authors.initials: W
authors.lastname: Hanna
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000378:metabolism / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000378:metabolism / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000096:biosynthesis*; D053553:Keratin-6 / Q000096:biosynthesis*; D008875:Middle Aged; D011230:Precancerous Conditions / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery
chemical_list: D053555:Keratin-5; D053553:Keratin-6