Original articleLymphocyte-predominant triple-negative breast carcinomas in premenopausal patients: Lower expression of basal immunohistochemical markers
Introduction
Triple-negative breast carcinomas (TNBCs) are defined by lack of estrogen and progesterone receptor expression, and the absence of overexpression and/or amplification of the erb-b2 receptor tyrosine kinase 2 (HER2). Although they are often associated with a basal-like genetic phenotype, 21.4% of them correspond to other molecular types, such as HER2-enriched (7.8%), normal (7.0%), luminal B (4.4%), and luminal A (2.2%) [1]. The basal-like phenotype of TNBCs was first defined by the immunohistochemical expression of basal cytokeratin 5/6 and/or epidermal growth factor receptor (EGFR) [2], [3]. TNBCs are more prevalent in young patients and they usually have a clinically aggressive behavior [4], [5].
Tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) are the main actors of the immune response and have been recognized as an important prognostic and predictive factor, particularly among estrogen receptor-negative carcinomas [6], [7], [8]. A meta-analysis study with 2987 patients with TNBCs and early stage showed that tumors rich in TILs have a 30% reduction in recurrence, 22% in distant recurrence, and 34% in death [9]. Lymphocyte-predominant breast cancers (LPBC) correspond to tumors with at least 50–60% of stromal TILs [10]. The International TILs Working Group provided a standardized methodology for evaluating TILs in BC [10]. The criteria were applied in a cohort of 897 TNBCs from the European Institute of Oncology [11]. The authors reported that patients with LPBC had better disease-free survival, distant disease-free survival and overall survival. In addition, they observed that each 10% increase in TILs strongly predicted better survival independent of other prognostic variables.
The heterogeneous morphologic, gene-expression profiles and genomic changes of TNBCs have been a challenge in finding of targets for therapy. It is clear that potential targets will work only in subsets of TNBCs. Candidates of these subsets are BRCA-1 mutant, BRCA1-like tumors with underlying defects in homologous recombination-mediated DNA repair and androgen-receptor positive tumors [12]. Successful subgroups based on immunohistochemical profile are lacking. The luminal androgen receptor subtype is characterized by the expression of this receptor [12], [13]. However, the prognostic value of androgen receptor is controversial [14], [15]. Other attempts on the classification of TNBC based on the immunohistochemical profile included p16, e-cadherin, claudins, and Ki-67 [16], [17]. Some immunohistochemical markers have been related to prognosis, for example, vimentin [18] and aldehyde dehydrogenase 1A1 (ALDH-1A1) [19].
In this study, our aim was to compare triple-negative LPBC with non-LPBC according to immunohistochemical profile.
Section snippets
Patients and methods
This project was approved by the Scientific Committee of the Department of Pathology and by the Ethical Committee for Research Projects of the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Brazil (CAPPesq) (protocol 311/10). As the study was retrospective, informed patient consent was waived, and any form of patient identification was abolished.
Formalin-fixed, paraffin-embedded tissue specimens from 116 consecutive patients aged 45 years or younger with
TMA construction
Tissue sections were stained with hematoxylin/eosin and the corresponding sections in each paraffin donor block were marked. Then one cylinder of the material (2.0 mm in diameter) was punched from each of these regions and these were mounted into recipient paraffin blocks at 2-mm intervals using a precision microarray instrument (Beecher Instruments, Silver Spring, MD, USA). A grid system was established such that each core had an x- and y-coordinate reference for sample identification. The
Immunohistochemistry and scoring
The following markers were selected for this study: Estrogen receptor (ER), progesterone receptor (PR), HER2, Ki-67, androgen receptor (AR), cytokeratin 5/6 (CK 5/6), cytokeratin 14 (CK 14), EGFR, vimentin, p16, claudin-3, -4, and -7, p63, and aldehyde dehydrogenase isoform 1 (ALDH1). The immunohistochemical detection of ER, PR, HER2 and Ki67 were performed in whole tumor sections. The other markers were evaluated on the TMA sections. Immunohistochemical studies were performed using the
Statistical analyses
Statistical analyses were performed using SPSS software, version 22.0 (SPSS, Chicago, IL, USA). Features of the LPBC and non-LPBC subgroups of the TNBCs were described and compared with Fisher's exact test (for categorical variables) or with the Mann-Whitney test (for patient age and Ki-67). The levels of percentage of TILs according the immunohistochemical markers were compared by the Mann-Whitney test. A p-value less than 0.05 was considered significant.
Results
The mean patients' age was 38.2 ± 4.9 years (range 26–45 years). Twenty-six (22.4%) patients present tumors classified as LPBC and 90 (77.6%) as non-LPBC. The mean patients' age was 37.4 ± 5.4 years and 38.4 ± 4.7 years, respectively (NS). Most of the tumors were of non-special histological type (107/116, 92.2%). LPBC present lower frequency of NST (20/26; 76.9% vs. 87/90; 96.7%) (p < 0.0001). All medullar carcinomas were, by definition, of LPBC group (5 cases). Most of the tumors were high
Discussion
TNBCs are more prevalent in young patients [5], [23], [24]. In addition, it appears that biological differences exist according to the age of patients [5], [25]. To avoid influence of age-dependent factors, such as menopausal status, we selected only patients of 45 years or less, for this study. The mean patient's age of our study group was 38.2 ± 4.9 years and there was no significant different in age between the two study groups, LPBC and non-LPBC.
The heterogeneity of TNBC remains an obstacle
Funding sources
This study was supported by São Paulo Research Foundation (FAPESP) (process 2014/15472-8).
Conflict of interest statement
None.
Ethical approval
This project was approved by the Scientific Committee of the Department of Pathology and by the Ethical Committee for Research Projects of the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Brazil (CAPPesq) (protocol 311/10).
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