Title: Characterization of Breast Cancer Subtypes by Immunohistochemistry in a Large Retrospective Study
Other Titles: Breast Cancer Subtypes
Authors: Decock, Julie
Hendrickx, Wouter
Stefan, Cristiana
Neven, Patrick
Wildiers, Hans
Christiaens, Marie-Rose
Smeets, Ann
Paridaens, Robert
Editors: Sinise, Geoffrey
Issue Date: 2007
Publisher: Nova Science Publishers, Inc.
Series Title: Tumor Markers Research Perspectives
Abstract: Background: DNA microarray studies identified distinct molecular subtypes that are associated with different clinical outcome, defined as luminal A, luminal B, basal-like and Her2+ER-. This study aimed to evaluate the immunohistochemistry markers ER, PR and Her2 as surrogate markers for the previously identified molecular subtypes in a large retrospective cohort (n=1678) with invasive breast carcinomas with regard to various demographic, clinical and pathological features.
Methods: All patients were diagnosed with primary breast cancer between 2000 and 2005 at the University Hospital Leuven. None of them received neo-adjuvant therapy, had bilateral cancer, tumors with direct extension to chest wall or skin, or nipple Paget’s disease. ER, PR and Her2 expression was determined by immunohistochemistry and cases with intermediary staining for Her2 were further subjected to two-color fluorescence in situ hybridization analysis. Clinical and pathological features included age at diagnosis, menopausal status, maximum tumor size, tumor grade, lymph node status and Nottingham Prognostic Index (NPI).

Results: Of the 1678 patients with invasive breast carcinoma, 80% (n=1342) had luminal A subtype, 7% (n=119) had luminal B subtype, 9% (n=144) had basal-like type and 4% (n=73) had Her2+/ER- carcinomas. Within the luminal type, the majority of cases were PR+, with 87% and 83% for the A and B subtypes, respectively. Luminal A carcinomas were more often small in size (p=0.037), well/moderately differentiated (p<0.00001) and associated with a lower NPI value (p<0.00001). Patients with a luminal B-type tumor presented more frequently with lymph node involvement (p=0.04) and were significantly younger at diagnosis (p=0.00012) compared to the other patients. Most basal-like and Her2+/ER- carcinomas were poorly differentiated (92% and 85% respectively). Furthermore, patients with luminal A or Her2+/ER- carcinomas were more often postmenopausal than patients with a luminal B or basal-like tumor (p=0.016).
Conclusions: In our large retrospective cohort of 1678 invasive breast cancers, the luminal A carcinomas were by far best represented in comparison with the other immunohistochemistry-defined (sub)types, and significantly associated with good prognostic clinical and pathological parameters. By contrast, although less represented, the luminal B, the basal-like and the Her2+ER- tumor (sub)types were more frequently associated with unfavourable prognostic factors such as younger age at diagnosis, lymph node involvement or poor histological grade.
ISBN: 978-1-60021-577-3
Publication status: published
KU Leuven publication type: IBa
Appears in Collections:Laboratory of Experimental Oncology
Gynaecological Oncology
Multidisciplinary Breast Clinic Section (-)
Surgical Oncology

Files in This Item:
File Description Status SizeFormat
Decock-PC.docbook chapter Published 246KbMicrosoft WordView/Open


All items in Lirias are protected by copyright, with all rights reserved.