Identification of a basal-like subtype of breast ductal carcinoma in situ.

Abstract

Microarray profiling of invasive breast carcinomas has identified subtypes including luminal A, luminal B, HER2-overexpressing, and basal-like. The poor-prognosis, basal-like tumors have been immunohistochemically characterized as estrogen receptor (ER)-negative, HER2/neu-negative, and cytokeratin 5/6-positive and/or epidermal growth factor receptor (EGFR)-positive. The aim of this study was to determine the prevalence of basal-like ductal carcinoma in situ in a population-based series of cases using immunohistochemical surrogates. A total of 245 pure ductal carcinoma in situ cases from a population-based, case-control study were evaluated for histologic characteristics and immunostained for ER, HER2/neu, EGFR, cytokeratin 5/6, p53, and Ki-67. The subtypes were defined as: luminal A (ER+, HER2-), luminal B (ER+, HER2+), HER2 positive (ER-, HER2+), and basal-like (ER-, HER2-, EGFR+, and/or cytokeratin 5/6+). The prevalence of breast cancer subtypes was basal-like (n = 19 [8%]); luminal A, n = 149 (61%); luminal B, n = 23 (9%); and HER2+/ER-, n = 38 (16%). Sixteen tumors (6%) were unclassified (negative for all 4 defining markers). The basal-like subtype was associated with unfavorable prognostic variables including high-grade nuclei (P < .0001), p53 overexpression (P < .0001), and elevated Ki-67 index (P < .0001). These studies demonstrate the presence of a basal-like in situ carcinoma, a potential precursor lesion to invasive basal-like carcinoma.

• Authors: Chad A Livasy, Charles M Perou, Gamze Karaca, David W Cowan, Diane Maia, Susan Jackson, Chiu-Kit Tse, Sarah Nyante, Robert C Millikan
• Journal: Human pathology (Hum Pathol) Vol. 38 Issue 2 Pg. 197-204 (Feb 2007) ISSN: 0046-8177 [Print] United States
• PMID: 17234468 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Keratin-5
• Keratin-6
• Ki-67 Antigen
• Receptors, Estrogen
• Tumor Suppressor Protein p53
• ErbB Receptors
• Receptor, ErbB-2

Topics

• Adult
• Aged
• Breast Neoplasms (classification, metabolism, pathology)
• Carcinoma, Intraductal, Noninfiltrating (classification, metabolism, pathology)
• ErbB Receptors (analysis)
• Female
• Humans
• Immunohistochemistry
• Keratin-5 (analysis)
• Keratin-6 (analysis)
• Ki-67 Antigen (analysis)
• Middle Aged
• Prognosis
• Receptor, ErbB-2 (analysis)
• Receptors, Estrogen (analysis)
• Tissue Array Analysis
• Tumor Suppressor Protein p53 (analysis)