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

• Published in: Human pathology Vol. 38; no. 2; pp. 197 - 204
• Main Authors: Livasy, Chad A., MD, Perou, Charles M., PhD, Karaca, Gamze, MSc, Cowan, David W., BS, Maia, Diane, MD, Jackson, Susan, MPA, Tse, Chiu-Kit, MSPH, Nyante, Sarah, MSPH, Millikan, Robert C., PhD, DVM
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.02.2007; Elsevier; Elsevier Limited
• Subjects: Adult; African Americans; Aged; Basal-like subtype; Biological and medical sciences; Breast cancer; Breast carcinoma; Breast Neoplasms - classification; Breast Neoplasms - metabolism; Breast Neoplasms - pathology; Carcinoma, Intraductal, Noninfiltrating - classification; Carcinoma, Intraductal, Noninfiltrating - metabolism; Carcinoma, Intraductal, Noninfiltrating - pathology; Ductal carcinoma in situ; Epidermal growth factor; Estrogen receptor–negative; Female; Genotype & phenotype; Gynecology. Andrology. Obstetrics; Humans; Hypotheses; Immunohistochemistry; Investigative techniques, diagnostic techniques (general aspects); Keratin-5 - analysis; Keratin-6 - analysis; Ki-67 Antigen - analysis; Mammary gland diseases; Mammography; Medical sciences; Middle Aged; Pathology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Prognosis; Receptor, Epidermal Growth Factor - analysis; Receptor, ErbB-2 - analysis; Receptors, Estrogen - analysis; Studies; Tissue Array Analysis; Tumor Suppressor Protein p53 - analysis; Tumors; Breast carcinoma; Ductal carcinoma in situ; Estrogen receptor–negative; Basal-like subtype; Estrogen receptor; Ductal carcinoma; Carcinoma in situ; Estrogen; Identification; Breast cancer; Malignant tumor; Breast ductal carcinoma in situ; Ovarian hormone; Mammary gland diseases; Anatomic pathology; Sex steroid hormone; Subtype; Estrogen receptor-negative; Hormonal receptor
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2006.08.017

Summary 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.