19p13.1 is a triple-negative-specific breast cancer susceptibility locus

The 19p13.1 breast cancer susceptibility locus is a modifier of breast cancer risk in BRCA1 mutation carriers and is also associated with the risk of ovarian cancer. Here, we investigated 19p13.1 variation and risk of breast cancer subtypes, defined by estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) status, using 48,869 breast cancer cases and 49,787 controls from the Breast Cancer Association Consortium (BCAC). Variants from 19p13.1 were not associated with breast cancer overall or with ER-positive breast cancer but were significantly associated with ER-negative breast cancer risk [rs8170 OR, 1.10; 95% confidence interval (CI), 1.05-1.15; P = 3.49 × 10(-5)] and triple-negative (ER-, PR-, and HER2-negative) breast cancer (rs8170: OR, 1.22; 95% CI, 1.13-1.31; P = 2.22 × 10(-7)). However, rs8170 was no longer associated with ER-negative breast cancer risk when triple-negative cases were excluded (OR, 0.98; 95% CI, 0.89-1.07; P = 0.62). In addition, a combined analysis of triple-negative cases from BCAC and the Triple Negative Breast Cancer Consortium (TNBCC; N = 3,566) identified a genome-wide significant association between rs8170 and triple-negative breast cancer risk (OR, 1.25; 95% CI, 1.18-1.33; P = 3.31 × 10(-13)]. Thus, 19p13.1 is the first triple-negative-specific breast cancer risk locus and the first locus specific to a histologic subtype defined by ER, PR, and HER2 to be identified. These findings provide convincing evidence that genetic susceptibility to breast cancer varies by tumor subtype and that triple-negative tumors and other subtypes likely arise through distinct etiologic pathways.     

Neutrophil/Lymphocyte and Platelet/Lymphocyte Ratios are Not Different among Breast Cancer Subtypes

Background: Breast cancer is a heterogeneous complex of diseases comprising different subtypes that have different treatment responses and clinical outcomes. Systemic inflammation is known to be associated with poor prognosis in many types of cancer. The neutrophil / lymphocyte ratio (NLR) and platelet / lymphocyte ratio (PLR) are factors used as indicators of inflammation. In this study, we evaluated NLR and PLR ratios in breast cancer subtypes. Methods: A total of 255 breast cancer patients were evaluated retrospectively. Patients were classified into three subtypes: estrogen receptor (ER)- or progesterone receptor (PR)-positive tumors were classified as luminal tumors; human epidermal growth factor receptor-2 (HER2)-overexpressed and ER-negative tumors were classified as HER2-positive tumors; and ER, PR, and HER2-negative tumors were classified as triple-negative tumors. The NLR and PLR were calculated. Results: The median NLR and PLR were 3 (0.37–37,1) and 137 (37.1–421.3), respectively. 66.7% of the patients were luminal type, 19.2% were HER2 positive, and 14.1% were triple negative. NLR was not associated with grade (p: 0.412), lymphovascular invasion (p: 0.326), tumor size (p: 0.232) and metastatic lymph node involvement (p: 0.406). PLR was higher in the patients with lymph node metastasis than in those without lymph node metastasis (p: 0.03). The NLR was 2 in the luminal group, 1.8 in the HER2-positive group, and 1.9 in the triple-negative group, but the differences were not significant(p: 0.051). PLR was 141 in the luminal group, 136 in the HER2-positive group, and 130 in the triple-negative group, but the differences were not significant. Conclusion: We could not find any significant differences for NLR and PLR according to breast cancer subtypes.     

Gene-expression analysis and the basal-like breast cancer subtype

Analysis of the patterns of gene expression in breast cancer suggests that it is not a single entity, but is comprised of several biologically distinct subtypes with characteristic molecular profiles. These molecular profiles confirm the clinical impression that estrogen receptor (ER)-negative differs from ER-positive, and expands our understanding by identifying breast cancer subtypes, including the basal-like and human epidermal growth factor receptor (HER)2/ER subtypes within the ER-negative subset, and the luminal A and B subtypes within ER-positive disease. The basal-like subtype is characterized by the low expression levels of the ER-related and the HER2-related group of genes, and therefore is often 'triple negative' on clinical assays for these proteins. This review discusses the molecular profiles of breast cancer with a focus on the clinical characteristics of, and treatment options for, the basal-like subtype.     

Systemic therapy for hormone receptor-positive/human epidermal growth factor receptor 2-negative early stage and metastatic breast cancer

Hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is defined by the presence of the estrogen receptor and/or the progesterone receptor and the absence of HER2 gene amplification. HR-positive/HER2-negative breast cancer accounts for 65%–70% of all breast cancers, and incidence increases with increasing age. Treatment varies by stage, and endocrine therapy is the mainstay of treatment in both early stage and late-stage disease. Combinations with cyclin-dependent kinase 4/6 inhibitors have reduced distant recurrence in the early stage setting and improved overall survival in the metastatic setting. Chemotherapy is used based on stage and tumor biology in the early stage setting and after endocrine resistance for advanced disease. New therapies, including novel endocrine agents and antibody-drug conjugates, are now changing the treatment landscape. With the availability of new treatment options, it is important to define the optimal sequence of treatment to maximize clinical benefit while minimizing toxicity. In this review, the authors first discuss the pathologic and molecular features of HR-positive/HER2-negative breast cancer and mechanisms of endocrine resistance. Then, they discuss current and emerging therapies for both early stage and metastatic HR-positive/HER2-negative breast cancer, including treatment algorithms based on current data.     

The Need to Examine Metastatic Tissue at the Time of Progression of Breast Cancer: Is Re-biopsy a Necessity or a Luxury?

Knowledge of estrogen receptor (ER), progesterone receptor (PgR) and human epidermal growth factor receptor-2 (HER2) status is necessary for determining the optimal treatment of breast cancer patients. At the same time, the discordance between marker profiles (ER/PR and HER2) of primary and metastatic breast cancer is well documented. Whether discordant cases are secondary to “clonal selection” in the face of targeted anti-estrogen or anti-HER2 therapy or whether they are a laboratory artifact is still debated; both scenarios are likely. This article outlines current modalities for ER, PR, and HER2 testing in primary breast carcinoma and its metastases and reviews prospective and retrospective studies that have addressed these issues, as well as recent advances in the field.     

The prognostic biomarkers HOXB13, IL17BR, and CHDH are regulated by estrogen in breast cancer.

PURPOSE: We previously identified three genes, HOXB13, IL17BR, and CHDH, that strongly predict clinical outcome in estrogen receptor (ER)-positive breast cancer patients receiving tamoxifen monotherapy. The biological mechanisms linking these genes to estrogen signaling and tamoxifen response in breast cancer remain to be determined. EXPERIMENTAL DESIGN: In a consecutive series of 148 ER-positive and ER-negative breast cancers, HOXB13, IL17BR, and CHDH gene expression was measured by quantitative real-time PCR and correlated with ER, PR, and HER2 expression. The role of estrogen and ER in the regulation of these three genes was assessed in several ER-positive and ER-negative breast cancer cell lines. RESULTS: In primary breast tumors, HOXB13 expression correlated negatively, and IL17BR and CHDH expression correlated positively, with ER status, and all three genes exhibited an ER-dependent correlation pattern with HER2 status that differs from PR and PS2, two canonical estrogen-regulated genes. Results using breast cancer cell lines show that these genes are regulated by estradiol in an ER-dependent manner, and that this regulation is abrogated by tamoxifen. CONCLUSIONS: HOXB13, IL17BR, and CHDH are estrogen-regulated genes, but their pattern of correlation with known positive (ER, PR) and negative (HER2) predictors of tamoxifen response differs from canonical ER signature genes. These results provide a biological rationale for the prognostic utility of these three genes in early-stage ER-positive breast cancer and for their potential to predict anti-estrogen resistance.     

Co-expressed type of ER and HER2 protein as a predictive factor in determining resistance to antiestrogen therapy in patients with ER-positive and HER2-positive breast cancer

The purpose of this study was to analyze whether inter-site variation types on estrogen receptor (ER) and HER2 expression may be a predictive factor for evaluating the effectiveness of endocrine therapy in patients with ER-positive and HER2-positive breast cancer. A total of 366 consecutive women with invasive breast cancer who had undergone curative surgical treatment between 1996 and 2001 were included in this study. ER status was evaluated using the Allred score and HER-2 status was evaluated according to the HercepTest. In ER-positive and HER2-positive tumors, the expression of ER and HER2 was described as the co-expressed type or the differently expressed type using double staining with ER and HER2. Of the 366 patients, 249 (68.1%) were positive for ER and 74 (20.2%) were positive for HER2. ER-positive and HER2-negative tumors were found in 221 patients (60.4%), ER-negative and HER2-negative in 71 (19.4%), ER-negative and HER-2-positive in 46 (12.6%), and ER-positive and HER2-positive in 28 (7.7%). HER2 status was inversely correlated (p<0.01) with ER status. In ER-positive tumors, an inverse correlation between ER and HER2 was also observed. The co-expressed type was found in 10 patients, and the differently expressed type was found in 18. There was no difference in tumor size and nodal involvement between the two types. There was no significant difference in disease-free survival between patients with the co-expressed type tumor and the differently expressed type tumor. In patients with the differently expressed type tumor, those who received antiestrogen therapy showed a significantly better disease-free survival rate than those who did not receive antiestrogen therapy. As for patients with the co-expressed type of tumor, no significant difference in disease-free survival was observed between patients with and without antiestrogen treatment. The present study suggests that the co-expressed type of tumour might be a resistant factor to antiestrogen therapy in ER-positive and HER2-positive breast cancer.     

Pathologic features and molecular phenotype by patient age in a large cohort of young women with breast cancer

Prior studies have suggested a higher prevalence of high grade, ER-negative, HER2-positive, and basal-like carcinomas in young women with breast cancer. However, the precise distribution of poor prognostic features in this population remains unclear. We examined the pathologic features and distribution of molecular phenotype in relation to patient age in a large group of young women (≤40?years) with invasive breast cancer. Medical records were reviewed for clinical characteristics, tumor stage, and receptor status. Pathologic features, including those features associated with basal-like carcinomas, were examined by central review. Using tumor grade and biomarker expression, cancers were categorized as luminal A (ER+ and/or PR+ and HER2-, histologic grade 1 or 2); luminal B (ER+ and/or PR+ and HER2+, or ER and/or PR+, HER2- and grade 3); HER2 (ER and PR- and HER2+); and triple negative (ER-, PR-, and HER2-). Among 399 women?of ≤40?years, 33% had luminal A tumors, 35% luminal B, 11% HER2 (ER-negative), and 21% triple negative. Compared to published results for all breast cancers, a greater proportion of young women had luminal B tumors, and a lesser proportion had luminal A. There were no significant differences in molecular phenotype, tumor stage or grade among the different age groups of young women. However, this population of young women presented with a different distribution of molecular phenotypes compared to the general population of women with breast cancer. These findings may have implications with regard to the etiology and prognosis of breast cancer in young women.     

Modulating therapeutic effects of the c-Src inhibitor via oestrogen receptor and human epidermal growth factor receptor 2 in breast cancer cell lines

Purposec-Src is an important adapter protein with oestrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2), which validates it as an attractive target for the treatment of breast cancer. A specific c-Src inhibitor, 4-amino-5-(4-chlorophenyl)-7(t-butyl)pyrazolo[3,4-d]pyrinidine (PP2), was utilised to block c-Src activity to identify targeted vulnerabilities affected by ER and HER2 in a panel of breast cancer cell lines.MethodsER, growth factor receptors and signalling pathways were detected by Western-blot. The DNA content of the cells was determined by using a DNA fluorescence quantitation kit. Cell cycles were analysed by flow cytometry.ResultsThe antiproliferative effect of PP2 closely correlated with the inhibition of c-Src mediated extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) and/or phosphoinositide 3-kinase (PI3K)/Akt growth pathways. Inhibition of c-Src tyrosine kinase predominantly blocked ER negative breast cancer cell growth, particularly the triple (i.e. ER, progesteron receptor (PR), and HER2) negative cells. In contrast, ER negative Sk-Br-3 cells with highest HER2 phosphorylation were resistant to PP2, in which hyper-activated HER2 directly regulated growth pathways. However, blocking c-Src recovered ER expression and down-regulated HER2 which made Sk-Br-3 cells regain responsiveness to 4-hydroxytamoxifen. The majority of ER positive cells were not sensitive to PP2 regardless of wild-type or endocrine resistant cell lines.Conclusionsc-Src mediates the essential role of growth pathways in ER negative breast cancer cells. The ER positive and HER2 over-activation are two important predictive biomarkers for the resistance to a c-Src inhibitor. These data provided an important therapeutic rationale for patient selection in clinical trials with c-Src inhibitors in breast cancer.     

Correlations between HER2 Expression and Other Prognostic Factors in Breast Cancer: Inverse Relations with the Ki-67 Index and P53 Status

Background: Overexpression or amplification of human epidermal growth factor receptor-2 (HER2) is associated with grade of malignancy and a poor prognosis in breast cancer (BC). The aim of this study was to evaluate of value of HER2 as a prognostic marker, and to analyze associations with common histopathological parameters in BC cases. Materials and Methods: Between of 2007 to 2014, 260 patients with BC referred to Oncology Clinic provided cancer tissue samples which underwent immunohistochemistry (IHC) for markers. ER and PR positivity was defined as 10% positive tumor cells with nuclear staining. HER2-positive was defined as either HER2 gene amplification by fluorescent in situ hybridization (FISH) or scored as 3 by IHC. For HER2 (2), FISH was performed to determine HER2 positivity. Results: The mean age at diagnosis for the patients with HER2-negative was significantly higher than in HER2-positive cases. Also, there were significant correlations between histological grade, nuclear grade, lymph node metastasis, tumor size, ER status, PR status, p53 overexpression and Ki-67 index with HER2 expression. HER2-negative lesions were of higher grade and more likely to be ER-negative, PR-negative, p53-positive, lymph node metastasis, with a tumor sizealso Ki-6720% as compared to the HER2-positive group. Conclusions: Contrary to the results of other studies, HER2-positive tumors in our study had a lower Ki-67 index and were p53-positive. Also, Ki-67 proliferation index 20% in more studies was associated with p53-positive.Therefore, tumors which are HER2-positive and have a Ki-6720% had a more aggressive behavior compared to HER2-positive and Ki-67<20% lesions.     

Breast cancer subtypes and survival in patients with brain metastases

Introduction

Brain metastases (BM) occur in up to one third of patients with metastatic breast cancer (MBC), whose incidences and prognoses by breast cancer subtypes in BM have not been well delineated.

Methods

Retrospective survival analyses were performed in 126 BM patients from 805 MBC patients treated at the National Cancer Center between August 2001 and April 2006, according to clinical characteristics, breast cancer subtypes, and receipt of trastuzumab. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth receptor-2 (HER2) statuses were tested by immunohistochemical (IHC) staining, and HER2 FISH analysis conducted for IHC 2+.

Results

The proportion of HER2+/ER- (29% vs 16%) and triple-negative (37% vs 25%) tumors was higher in the 126 BM patients than those without BM. While median survival after recurrence was longer in patients with luminal A disease (median survival of luminal A vs luminal B vs HER2+/ER- vs triple-negative: p = 0.0246; 39.6 vs 27.4 vs 20.9 vs 15.5 months), survival was shorter from BM to death in luminal A and triple negatives (median survival: p = 0.0113; 4.0 vs 9.2 vs 5.0 vs 3.4 months). Receipt of trastuzumab after BM was a significant variable for survival in HER2+ patients. Multivariate analyses identified ER-negative, HER2-negative, or triple-negative, as well as older age, presence of leptomeningeal disease, and three or more extracranial disease sites, as poor prognostic factors for survival after BM.

Conclusion

MBC patients who developed BM had higher proportions of triple-negative and HER2+/ER- tumor status. Triple receptor status is a useful prognostic marker for predicting survival after BM in metastatic breast cancer patients.     

Discrepancies between biomarkers of primary breast cancer and subsequent brain metastases: an international multicenter study

Purpose

Discordances between the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), expression between primary breast tumors and their subsequent brain metastases (BM) were investigated in breast cancer patients.

Methods

We collected retrospective data from 11 institutions in 8 countries in a predefined-standardized format. Receptor status (positive or negative) was determined according to institutional guidelines (immunohistochemically and/or fluorescence in situ hybridization). The study was subject to each institution’s ethical research committee.

Results

A total of 167 breast cancer patients with BM were included. 25 patients out of 129 with a complete receptor information from both primary tumor and BM (ER, PR, HER2) available, had a change in receptor status: 7 of 26 (27%) ER/PR-positive/HER2-negative primaries (3 gained HER2; 4 lost expression of ER/PR); 10 of 31 (32%) ER/PR-positive/HER2-positive primaries (4 lost ER/PR only; 3 lost HER2 only; 3 lost both ER/PR and HER2); one of 33 (3%) ER/PR-negative receptor/HER2-positive primaries (gained ER); and 7 of 39 (18%) triple-negative primaries (5 gained ER/PR and 2 gained HER2).

Conclusions

The majority of breast cancer patients with BM in this series had primary HER2-enriched tumors, followed by those with a triple-negative profile. One out of 5 patients had a receptor discrepancy between the primary tumor and subsequent BM. Therefore, we advise receptor status assessment of BM in all breast cancer patients with available histology as it may have significant implications for therapy.

     

Breast Cancer With Brain Metastases: Clinicopathologic Features,Survival, and Paired Biomarker Analysis

Background.

The aim of this study was to describe clinicopathologic features of patients with breast cancer brain metastasis (BCBM); to evaluate survival after diagnosis of BCBM; and to compare estrogen receptor (ER), progesterone receptor (PR), and HER2 expression in the paired primary and brain tumors.

Materials and Methods.

We identified 140 consecutive patients who underwent craniotomy for BCBM (either for diagnostic purpose or with therapeutic intent) at the University of Texas MD Anderson Cancer Center between 2002 and 2009.

Results.

Most patients had invasive ductal histology (91%), grade 3 tumors (67%), and positive axillary lymph node (64%). Of the tumors, 56% were ER-negative, 62% were PR-negative, 44% were HER2-positive, and 28% were triple negative (TN). Brain metastasis (BM) was solitary in 51% of patients. Median interval from breast cancer diagnosis to BM was 46 months; median survival after BM was 14.1 months. In the univariate analysis, younger age, solitary brain metastasis, and ER or PR positivity in the breast tumors were associated with longer survival. There was a statistical trend toward increased survival in HER2-positive patients compared with HER2-negative patients (18 vs. 11 months). In the multivariate analysis, predictors for longer survival included younger age, solitary brain lesion, and HER2 positivity in the breast cancer. Biomarkers were evaluated in paired primary and brain tumors in 35 patients for ER status, 34 for PR status, and 36 for HER2 status. Discordant rates were 28% for ER, 20% for PR, and 3% for HER2.

Conclusion.

Compared with unselected breast cancer patients at the same institution, patients with breast cancer who had brain metastases had a higher proportion of hormone receptor-negative, HER2-positive, and TN tumors. Younger age, solitary brain lesion, and HER2 expression were independent predictors of better survival in patients with BCBM. HER2 status was highly concordant between the paired primary and brain tumors, whereas changes of ER and PR status occurred in a substantial proportion of the patients. These findings are important for making effective treatment decisions for patients with BCBM.     

Targeting the HER/EGFR/ErbB family to prevent breast cancer

Preventing breast cancer is possible with selective estrogen receptor (ER) modulators and aromatase inhibitors, which reduce the risk of invasive disease by up to 65% (up to 73% for ER-positive and no effect for ER-negative cancer) and the risk of preinvasive disease [ductal carcinoma in situ (DCIS)] by up to 50%. Clearly, approaches for preventing ER-negative, and increased prevention of ER-positive breast cancers would benefit public health. A growing body of work (including recent preclinical and clinical data) support targeting the HER family [epidermal growth factor receptor (EGFR), or human epidermal growth factor receptor (HER) 1 or ErbB1) and HER2, HER3, and HER4] for preventing ER-negative and possibly ER-positive breast cancer. Preclinical studies of HER family-targeting drugs in mammary neoplasia show suppression of (i) ER-negative tumors in HER2-overexpressing mouse strains, (ii) ER-negative tumors in mutant Brca1/p53(+/-) mice, and (iii) ER-positive tumors in the methylnitrosourea (MNU) rat model; tumors arising in both the MNU and mutant Brca1/p53(+/-) models lack HER2 overexpression. Clinical trials include a recent placebo-controlled phase IIb presurgical trial of the dual EGFR HER2 inhibitor lapatinib that suppressed growth of breast premalignancy [including atypical ductal hyperplasia (ADH) and DCIS] and invasive cancer in patients with early-stage, HER2-overexpressing or -amplified breast cancer. These results suggest that lapatinib can clinically suppress the progression of ADH and DCIS to invasive breast cancer, an effect previously observed in a mouse model of HER2-overexpressing, ER-negative mammary cancer. The preclinical and clinical signals provide a compelling rationale for testing HER-targeting drugs for breast cancer prevention in women at moderate-to-high risk, leading perhaps to combinations that prevent ER-negative and ER-positive breast cancer.     

Can molecular markers predict when to implement treatment with aromatase inhibitors in invasive breast cancer?

PURPOSE: Resistance to tamoxifen is linked to overexpression of HER2, and aromatase inhibitors show particular benefit in progesterone receptor (PR)-negative patients. We previously reported reduced survival in patients overexpressing HER1, HER2, and HER3. We now show that both HER1-3 and PR status predicts for early relapse in estrogen receptor (ER)-positive tamoxifen-treated breast cancer patients. EXPERIMENTAL DESIGN: Tissue microarray technology was used to analyze 402 ER-positive tamoxifen-treated patients. Immunohistochemistry using epidermal growth factor receptor, HER2, HER3, HER4, and PR antibodies was done. Kaplan-Meier life table and Cox Regression analysis (log-rank testing of differences in breast cancer-related relapse on tamoxifen) was done. RESULTS: HER1-3 (but not HER4) overexpression predicted for early relapse on tamoxifen (P = 0.0060). PR-negative cases were also significantly more likely to relapse while on tamoxifen (P= 0.017). HER1-3-positive and/or PR-negative patients combined as a "high-risk" group were significantly more likely to relapse on tamoxifen in univariate (P < 0.0001) and Cox's multivariate analysis (P = 0.0069). However, this applied to early relapse on tamoxifen only, as any disease relapse after 3 years of tamoxifen was unrelated to PR/HER status. CONCLUSIONS: We show that HER1-3 and PR status can identify time-dependent de novo tamoxifen resistance with risk declining markedly after 3 years of tamoxifen treatment. These results parallel data from the ATAC and Intergroup Exemastane Study trials which suggest that whereas PR-negative patients derive greater benefit from initial aromatase inhibitor treatment, PR status has no effect on response when given as delayed treatment to those disease free on tamoxifen after 3 years.     

Therapeutic implications of estrogen receptor signaling in HER2-positive breast cancers

There is considerable pre-clinical and clinical evidence demonstrating that HER2-positive breast cancers that express estrogen receptor (ER) exhibit intrinsic resistance to endocrine therapy. Therefore, in general, chemotherapy in combination with HER2-directed agents is recommended for all but the smallest HER2-positive early stage breast cancers regardless of ER status. This paradigm has recently come into question when responses to neo-adjuvant HER2-directed regimens were noted to vary based on ER expression, and pathologic complete response was noted not to be prognostic for ER-positive, HER2-positive breast cancers. These and other data suggest the possibility that a subset of HER2-positive, ER-positive breast cancers are driven primarily by ER, and biologically behave more like HER2-negative, ER-positive breast cancers. Identification of this subset of HER2-positive breast cancers is essential to avoid over-treatment of patients with small HER2-positive, ER-positive breast cancers, who may be optimally treated with endocrine therapy alone, or in combination with a HER2-directed agent, thereby avoiding the use of chemotherapy. Crosstalk between the ER and HER2 pathways has been established as playing a role in both intrinsic and acquired resistance to endocrine agents. Emerging data suggests that crosstalk between these pathways is also involved in resistance to HER2-directed agents. Unraveling the role of the ER pathway in resistance to HER2-directed agents could potentially result in therapeutic approaches that can improve outcome for patients with ER-positive, HER2-positive breast cancer.     

Antitumor and anticancer stem cell activity of a poly ADP-ribose polymerase inhibitor olaparib in breast cancer cells

Background

Although the poly adenosine diphosphate (ADP)-ribose polymerase (PARP) inhibitor olaparib is known to have potent antitumor activity in BRCA-related breast cancer cells, a limited number of preclinical and clinical studies have shown antitumor activity of olaparib in non-BRCA-related breast cancer. We investigated antitumor activity of olaparib in breast cancer cell lines derived from patients with nonfamilial sporadic breast cancer.

Methods

Effects of olaparib alone or in combination with five different chemotherapeutic agents on cell growth, cell cycle progression, apoptosis, and proportion of cancer stem cells using the mammosphere assay and CD44/CD24/ESA cell surface marker assay were investigated in a panel of six sporadic breast cancer cell lines. Extracellular-signal-regulated kinase (ERK) phosphorylation was also investigated to elucidate action mechanisms of olaparib.

Results

Olaparib inhibited the growth of two estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer cell lines and two ER-negative and HER2-negative breast cancer cell lines (50 % growth inhibitory concentrations 1.3–3.0 μM) associated with G2/M accumulation and induction of apoptosis. In contrast, two HER2-positive cell lines were resistant to olaparib. Interestingly, olaparib significantly decreased the proportion of putative cancer stem cells in either sensitive or resistant cell lines. In addition, olaparib increased expression of p-ERK. Combined treatments of olaparib with a mitogen-activated protein kinase kinase (MEK) inhibitor U0126 completely suppressed expression of p-ERK. These treatments also inhibited the G2/M accumulation and apoptosis induction by olaparib. Among five chemotherapeutic agents commonly used for breast cancer treatment, only an irinotecan metabolite SN38 showed additive antitumor activity with olaparib. Importantly, the combined treatment enhanced the increase in G2/M accumulation and apoptosis induction as well as a decrease in the proportion of cancer stem cells.

Conclusions

This study has indicated for the first time that the PARP inhibitor olaparib has substantial antitumor and anticancer stem cell activity in breast cancer cell lines of nonfamilial origin. Upregulation of p-ERK might explain, at least in part, antitumor and anticancer stem cell activity of olaparib. Combined treatment of olaparib with irinotecan might be effective in treatment of non-BRCA-related breast cancer.     

Molecularly targeted therapies for metastatic triple-negative breast cancer

Triple-negative breast cancer (TNBC) refers to a heterogeneous group of tumors that do not express the estrogen/progesterone-receptor (ER/PR), and human epidermal growth factor receptor-2 (HER2). TNBC is an aggressive histological subtype with limited treatment options and very poor prognosis following progression after standard chemotherapy regimens. There have been significant improvements in the outcome of other subtypes of breast cancer, including ER-positive/HER2 overexpressed tumors, attributed to the addition of targeted therapy, including hormonal agents and trastuzumab. However, no specific targeted agents are currently available for the treatment of TNBC. This review aims to collate and describe the most recent data on targeted therapies that have demonstrated efficacy in the management of metastatic TNBC. Targeted agents that have been investigated in the treatment of metastatic TNBC include inhibitors of poly(ADP-ribose) polymerase, angiogenesis, mammalian target of rapamycin, epidermal growth factor receptor, HDAC, Jak2, and Src. Several of these agents have shown considerable promise.     

乳腺癌临床病理指标以及分子分型对TEC新辅助化疗病理完全缓解的预测价值

目的  本研究旨在探讨乳腺癌临床病理指标以及乳腺癌分子分型对多西他赛联合表柔比星、环磷酰胺（TEC）的 新辅助化疗后病理完全缓解率（pathological complete response pCR）的预测价值。方法   对 214例经4周期TEC新辅助化疗的乳腺癌患者的临床病理资料进行回顾性分析;免疫组织化学检测经核心针穿刺 的癌组织雌激素受体（ER）、孕激素受体（PR）、人类表皮生长因子受体-2（HER2）、Ki67、p53表达情况,原位基 因免疫荧光杂交（FISH）检测HER2有无过表达;根据ER、PR、HER2、Ki67的表达情况将乳腺癌分为4种分子分型： LuminalA、 LuminalB、HER2过表达型和三阴性乳腺癌。分析不同的临床病理指标、不同分子分型与pCR的相关性。结果  4周期TEC新辅助化疗后pCR率为14.0%（30/214）;单因素分析：ER、PR、Ki67、乳腺癌分子分型与pCR均具有显 著相关性（P＜0.05）;乳腺癌分子分型各组间显示pCR率不同：LuminalA＜LuminalB＜HER2过表达型＜三阴性乳腺癌 ;多因素分析：与pCR具有显著相关性的分类变量为ER（OR=0.311,95%CI：0.136～0.712;P=0.006）和Ki67 （OR=2.788,95%CI：1.061～7.327;P=0.038）。结论  ER、PR、Ki67以及乳腺癌分子分型可能是TEC新辅助化疗后乳腺癌pCR的预测指标。     

The Case to Case Comparison of Hormone Receptors and HER2 Status between Primary Breast Cancer and Synchronous Axillary Lymph Node Metastasis

Background: Nowadays, the adjuvant treatment for breast cancer patients chosen depends on immunohistochemical pattern of Estrogen receptor(ER), Progesterone receptor(PR) and HER2 status of primary breast tumor. Several retrospective studies showed significant discordance in receptor expression between primary and metastatic tumors. The objective of this research was to determine discordant rate of ER, PR and HER2 status between primary breast cancer and synchronous axillary lymph node metastasis of individual breast cancer patients in Thammasat University Hospital. Methods: A prospective observational study of all breast cancer patients who have axillary metastasis and underwent surgery at Thammasat Hospital between January 2011 to December 2015. Tumor staging, ER, PR, and HER2 status on primary breast tumor were recorded. Synchronous axillary lymph node metastasis was evaluated with immunohistochemistry for ER, PR, and HER2. Results: The ER-positive rate from primary tumor to synchronous axillary lymph node metastasis decreased from 74.7% to 71.7%; the HER2 overexpression rate was decreased from 26% to 24%. In contrast, PR positive rate were 71% in both primary tumor and synchronous axillary lymph node metastasis. In case to case comparison, discordance rate of ER, PR and HER2 status between primary breast cancer and synchronous axillary lymph node metastasis were 11.1%, 20.2% and 10.1%, respectively. Furthermore, the tumor staging was not significant associated with discordance of ER, PR and HER2. Conclusion: ER, PR and HER 2 biomarkers showed significant concordance between primary tumor and synchronous axillary lymph node metastasis. Hence, if we cannot assess the ER, PR and HER2 status in primary tumor, then synchronous axillary lymph node metastasis can be studied instead. However, the repeat of biomarker testing in node-positive breast cancer patients may be beneficial for tailored adjuvant therapy, especially for patients with negative hormone receptor and/or HER2 profile on primary tumor.