Prognostic value of proliferation assay in the luminal, HER2-positive, and triple-negative biologic classes of breast cancer
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ICR Authors
Authors
Aleskandarany, MA
Green, AR
Benhasouna, AA
Barros, FF
Neal, K
Reis-Filho, JS
Ellis, IO
Rakha, EA
Green, AR
Benhasouna, AA
Barros, FF
Neal, K
Reis-Filho, JS
Ellis, IO
Rakha, EA
Document Type
Journal Article
Date
2012-02-01
Date Accepted
Abstract
<jats:title>Abstract</jats:title><jats:sec>
<jats:title>Introduction</jats:title>
<jats:p>Although the prognostic significance of proliferation in early invasive breast cancer has been recognized for a long time, recent gene-expression profiling studies have reemphasized its biologic and prognostic value and the potential application of its assessment in routine practice, particularly to define prognostic subgroups of luminal/hormone receptor-positive (HR<jats:sup>+</jats:sup>) tumors. This study aimed to assess the prognostic value of a proliferation assay by using Ki-67 immunohistochemistry as compared with mitotic count scores.</jats:p>
</jats:sec><jats:sec>
<jats:title>Method</jats:title>
<jats:p>Proliferation was assessed by using Ki-67 labeling index (Ki-67LI) and mitotic scores in a large (<jats:italic>n</jats:italic> = 1,550) and well-characterized series of clinically annotated primary operable invasive breast cancer with long-term follow-up. Tumors were phenotyped based on their IHC profiles into luminal/HR<jats:sup>+</jats:sup>, HER2<jats:sup>+</jats:sup>, and triple-negative (TN) classes. We used a split-sample development and validation approach to determine the optimal Ki-67LI cut-offs.</jats:p>
</jats:sec><jats:sec>
<jats:title>Results</jats:title>
<jats:p>The optimal cut-points of Ki-67LI were 10% and 50% for the luminal class. Both Ki7LI and MS were able to split luminal tumors into subgroups with significantly variable outcomes, independent of other variables. Neither mitotic count scores nor Ki-67LI was associated with outcome in the HER2<jats:sup>+</jats:sup> or the TN classes.</jats:p>
</jats:sec><jats:sec>
<jats:title>Conclusions</jats:title>
<jats:p>Assessment of proliferation by using Ki-67LI and MS can distinguish subgroups of patients within luminal/hormone receptor-positive breast cancer significantly different in clinical outcomes. Overall, both Ki-67 LI and mitotic-count scores showed comparable results. The method described could provide a cost-effective method for prognostic subclassification of luminal/hormone receptor-positive breast cancer in routine clinical practice.</jats:p>
</jats:sec>
Citation
BREAST CANCER RESEARCH, 2012, 14
DOI
Source Title
Publisher
Springer Science and Business Media LLC
ISSN
1465-542X
eISSN
Collections
Research Team
Molecular Pathology