title: Frequent KIT and epidermal growth factor receptor overexpressions in undifferentiated-type breast carcinomas with 'stem-cell-like' features.
abstract: It was hypothesized that four histopathological types or subtypes of breast carcinoma were undifferentiated types characterized by bidirectional differentiation toward both luminal epithelial and myoepithelial cells and had characteristic molecular changes: invasive ductal carcinoma (IDC) with a large central acellular zone, atypical medullary carcinoma (a subgroup in Grade 3 solid-tubular carcinoma), matrix-producing carcinoma, and spindle-cell carcinoma (or carcinoma with spindle-cell metaplasia). In 32 cases of the undifferentiated type and 37 cases of the relatively differentiated types, we immunohistochemically examined the expressions of myoepithelial markers and KIT, epidermal growth factor receptor (EGFR), and c-erbB-2 oncoproteins. Vimentin, S-100, and alpha-smooth muscle actin were positive in 28 (88%), 22 (69%), and 15 (47%) of the undifferentiated types, but were positive in seven (19%), one (3%), and one (3%) of relatively differentiated types (P < 0.0001). KIT and EGFR overexpressions were detected more frequently in the undifferentiated types (34 and 88%, respectively) than in relatively differentiated types (3 and 3%, respectively) (P < 0.0001, for both). In 11 (85%) of 13 cases with KIT overexpression, EGFR overexpression concurred. c-erbB-2 overexpression was almost equally detected in both the undifferentiated and relatively differentiated types, and did not correlate with KIT or EGFR overexpression. Phosphotyrosine was detected in 16 (67%) of 24 cases with KIT, EGFR, and/or c-erbB-2 overexpression but only in six (18%) of 34 cases without KIT, EGFR, or c-erbB-2 overexpression (P = 0.0002). The undifferentiated-type breast carcinomas appeared to show mammary epithelial stem cell-like features, and they could be identified by KIT and/or EGFR overexpressions.
authors.affiliation: Department of Pathology II, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. htsuda@ndmc.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tsuda
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Tani
authors.forename: Joel
authors.initials: J
authors.lastname: Weisenberger
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kitada
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Murata
authors.forename: Seiichi
authors.initials: S
authors.lastname: Tamai
authors.forename: Setsuo
authors.initials: S
authors.lastname: Hirohashi
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsubara
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Natori
mesh_terms: D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology*; D044584:Carcinoma, Ductal / Q000235:genetics* / Q000473:pathology*; D002454:Cell Differentiation; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis* / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis; D013234:Stem Cells
chemical_list: D014408:Biomarkers, Tumor; D066246:ErbB Receptors; D019009:Proto-Oncogene Proteins c-kit; D018719:Erb-b2 Receptor Tyrosine Kinases