title: Epithelial hyperplasia of usual type expresses both S100-alpha and S100-beta in a heterogeneous pattern but ductal carcinoma in situ can express only S100-alpha in a monotonous pattern.
abstract: Immunohistochemical identification of myoepithelial cells using alpha-smooth muscle actin provides little information about the nature of solid or quasi-solid portions of epithelial hyperplasia and ductal carcinoma in situ (DCIS) because actin-rich myoepithelial cells are usually demonstrated only in the stromal-epithelial junction of both lesions. We studied the differential distribution of alpha-subunit (S100-alpha) and beta-subunit (S100-beta) of S100 protein in actin-negative areas of usual epithelial hyperplasia and DCIS by employing the streptavidin method with monospecific rabbit antibodies against each subunit. All usual epithelial hyperplasias (n = 17) were composed of heterogeneous epithelial cell types; cells expressing S100-alpha and/or S100-beta were intermingled with non-expressing cells, resulting in a mosaic-like pattern. On the contrary, DCIS (n = 32) uniformly lacked immunoreactive S100-beta; S100-alpha was diffusely expressed in 24 (68.8%) DCIS (three solid/comedo, 13 cribriform, four endocrine, one micropapillary, three papillary variants) and negative in the remaining eight (31.2%) DCIS (one cribriform, two micropapillary, four papillary and one apocrine variants). In conclusion, in contrast to usual epithelial hyperplasia that expresses both S100-alpha and S100-beta in a heterogeneous pattern, DCIS can express only S100-alpha in a monotonous pattern, possibly signifying unidirectional differentiation toward secretory glandular epithelium.
authors.affiliation: Department of Pathology, Nagoya National Hospital, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ichihara
authors.forename: T
authors.initials: T
authors.lastname: Koshikawa
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Yatabe
authors.forename: K
authors.initials: K
authors.lastname: Kato
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002278:Carcinoma in Situ / Q000378:metabolism*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D008875:Middle Aged; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C110294:S100A1 protein; C579160:S100B protein, human