Laminin 5 expression in metaplastic breast carcinomas

• Published in: The American journal of surgical pathology Vol. 32; no. 3; p. 345
• Main Authors: Carpenter, Philip M, Wang-Rodriguez, Jessica, Chan, Owen T M, Wilczynski, Sharon P
• Format: Journal Article
• Language: English
• Published: United States 01.03.2008
• Subjects: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor - analysis; Breast Neoplasms - chemistry; Carcinoma - chemistry; Carcinoma, Squamous Cell - chemistry; Cell Adhesion Molecules - analysis; Female; Humans; Immunohistochemistry; Kalinin; Keratin-5 - analysis; Keratin-6 - analysis; Membrane Proteins - analysis; Metaplasia; Middle Aged; Receptors, Estrogen - analysis; Receptors, Progesterone - analysis
• ISSN: 0147-5185
• DOI: 10.1097/PAS.0b013e3181592201

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.