title: Laminin 5 expression in metaplastic breast carcinomas.
abstract: Metaplastic carcinoma of the breast shows squamous, sarcomatous, or chondromatous differentiation and has a poor prognosis. Laminin 5 is a heterotrimer of alpha3, beta3, and gamma(2) [corrected] chains and induces aggressive properties in cancer cells including motility, invasion, and epithelial to mesenchymal transition. Twenty-five cases included 7 squamous, 4 sarcomatous, 8 chondroid, 1 fibromatosislike metaplastic carcinomas, and 5 cases with 2 metaplastic components. Tumors were stained with laminin 5-specific beta3 and gamma(2) [corrected] chain, p63, and cytokeratin 5/6 (CK 5/6) antibodies. All 4 antibodies stained normal myoepithelium. Both laminin 5 antibodies stained 24/25 (96%) of the tumors, with an identical distribution of the 2 chains in 87.5% of the positively staining cases. In contrast, p63 and CK 5/6 stained 68% and 64% of the tumors, respectively. By comparison, only 16% of high-grade carcinoma controls stained for laminin 5. Similar to the metaplastic carcinomas, all 12 triple negative tumors, those negative for estrogen receptor, progesterone receptor, and Her2/neu, expressed laminin 5. None of 4 breast sarcomas stained for either of the laminin 5 chains or CK 5/6, but 1 (25%) stained for p63. Laminin 5 expression in metaplastic and other basal-like carcinomas is of interest for several reasons. First, these data provide additional evidence of the myoepithelial and basal-like phenotype of these carcinomas. Second, these are the only breast carcinoma subtypes to demonstrate laminin 5 staining in a large proportion of cases. Third, expression of laminin 5 in metaplastic carcinomas may suggest a mechanism for their increased aggressiveness and epithelial to mesenchymal transition phenotype. Finally, compared with other myoepithelial markers, laminin 5 is more sensitive than those previously published. Thus laminin 5 may be helpful for making the diagnosis of metaplastic carcinomas in biopsies, allowing the potential for aggressive early treatment. Further study of other basal-like tumors for laminin 5 expression is warranted to determine the usefulness of laminin 5 in their diagnosis.
authors.affiliation: The Department of Pathology and Laboratory Medicine, The University of California, Orange, CA 92868, USA. pmcarpen@uci.edu
authors.forename: Philip M
authors.initials: PM
authors.lastname: Carpenter
authors.forename: Jessica
authors.initials: J
authors.lastname: Wang-Rodriguez
authors.forename: Owen T M
authors.initials: OT
authors.lastname: Chan
authors.forename: Sharon P
authors.initials: SP
authors.lastname: Wilczynski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry*; D002277:Carcinoma / Q000737:chemistry*; D002294:Carcinoma, Squamous Cell / Q000737:chemistry; D015815:Cell Adhesion Molecules / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000032:analysis; D053553:Keratin-6 / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D008679:Metaplasia; D008875:Middle Aged; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D000097794:Kalinin
chemical_list: D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; D053555:Keratin-5; D053553:Keratin-6; D008565:Membrane Proteins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000097794:Kalinin; C081876:CKAP4 protein, human