title: The unique luminal staining pattern of cytokeratin 5/6 in adenoid cystic carcinoma of the breast may aid in differentiating it from its mimickers.
abstract: Adenoid cystic carcinoma (AdCC) of the breast is an uncommon but distinct neoplasm composed of a dual cell population polarized around true glandular (luminal) spaces and pseudolumina. The aim of this study was to clarify whether various immunohistochemical markers (CK7, EMA, CD117, p63, calponin, CD10, S100, CK5/6, CK14, vimentin, and type IV collagen) can distinguish between the two cell types in classical AdCC (n = 14) and in collagenous spherulosis (n = 5). The sensitivity and specificity of these 11 markers to distinguish luminal from abluminal cells were evaluated using a curve created by plotting the true-positive rate (sensitivity) against the false-positive rate (1 - specificity) at threshold settings of 0, 10, 50, and 70 %. The most sensitive and specific markers for luminal cells in AdCC were CK7 and EMA; those for abluminal cells were type IV collagen, p63, and vimentin. CD10 and S100 did not act as abluminal markers in AdCC. CK5/6, one of the basal/myoepithelial markers, was expressed more frequently in luminal than in abluminal cells of AdCC. Thus, CK5/6 immunostaining resulted in a reverse expression pattern, analogous to what we recently documented in clear cells in mammary adenomyoepithelioma. In conclusion, compared with myoepithelial/abluminal cells of normal breast or collagenous spherulosis, the neoplastic abluminal cells of classical AdCC are characterized by enhanced vimentin and attenuated CD10 and S100. Furthermore, the luminal cells of AdCC show a unique aberrant staining pattern for CK5/6 that may aid in the differential diagnosis.
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Tokiko
authors.initials: T
authors.lastname: Nakai
authors.affiliation: Department of Pathology, Clinical Research Center, Nagoya Medical Center, 4-1-1 Sannomaru, Naka-ku, Nagoya, Aichi, Japan. patho@nnh.hosp.go.jp.
authors.forename: Shu
authors.initials: S
authors.lastname: Ichihara
authors.affiliation: Department of Clinical Trials and Research, Clinical Research Center, Nagoya Medical Center, Nagoya, Aichi, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Kada
authors.affiliation: Department of Clinical Research Management, Clinical Research Center, Nagoya Medical Center, Nagoya, Aichi, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Ito
authors.affiliation: Department of Pathology, Shiga Medical University, Otsu, Shiga, Japan.
authors.forename: Suzuko
authors.initials: S
authors.lastname: Moritani
authors.affiliation: Department of Molecular Diagnostic Pathology, Iwate Medical University School of Medicine, Morioka, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Uchiyama
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Hiroe
authors.initials: H
authors.lastname: Itami
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Kouhei
authors.initials: K
authors.lastname: Morita
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Takano
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Takeda
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Kinta
authors.initials: K
authors.lastname: Hatakeyama
authors.affiliation: Department of Pathology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Ohbayashi
mesh_terms: D055331:Adenomyoepithelioma / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D003528:Carcinoma, Adenoid Cystic / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D003937:Diagnosis, Differential; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D053555:Keratin-5 / Q000378:metabolism*; D053553:Keratin-6 / Q000378:metabolism*; D008875:Middle Aged; D009208:Myoepithelioma / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D053555:Keratin-5; D053553:Keratin-6
keywords: Adenoid cystic carcinoma; Collagenous spherulosis; Cytokeratin 5/6; Myoepithelial cells; Vimentin