Use of immunohistochemical markers can refine prognosis in triple negative breast cancer

Basal markers and prognosis in luminal breast cancer

PURPOSE

Basal marker expression in triple-negative breast cancers identifies basal-like tumours, and thus separates the TN group into two prognostic groups. However, the expression and prognostic significance of basal markers in luminal breast cancers are poorly described. The aim of this study was to investigate the expression and prognostic value of basal markers (CK5, CK14 and EGFR) in luminal breast cancer.

METHODS

A total of 1423 formalin-fixed, paraffin-embedded breast cancer tumours from a well-characterized cohort of Norwegian women, previously reclassified into molecular subtypes using IHC and ISH, were included in the study. For the present study, tumours expressing at least one of the basal markers CK5, CK14 or EGFR were defined as basal marker positive. Cumulative incidence of death from breast cancer and hazard ratio analyses were used to assess prognosis according to basal marker expression.

RESULTS AND CONCLUSION

In total, 470 cases (33.0%) were basal marker positive. A higher proportion of the basal marker-positive tumours were of histopathological grade 3 compared to basal marker negative. For hormone receptor-positive, HER2-negative cases, we found better prognosis for basal marker-positive breast cancer compared to basal marker negative. For all subtypes combined, poorer prognosis for basal marker-negative cases was found in histopathological grade 2 tumours but not among grade 1 and 3.

Bioinformatics analysis of the prognostic value of Tripartite Motif 28 in breast cancer

Tripartite motif containing 28 (TRIM28) is a transcriptional regulator acting as an essential corepressor for Krüppel-associated box zinc finger domain-containing proteins in multiple tissue and cell types. An increasing number of studies have investigated the function of TRIM28; however, its prognostic value in breast cancer (BC) remains unclear. In the present study, the expression of TRIM28 was identified to be significantly higher in cancerous compared with healthy tissue samples. Furthermore, it was demonstrated that TRIM28 expression was significantly correlated with several clinicopathological characteristics of patients with BC, such as p53 mutation, tumor recurrence and Elston grade of the tumor. In addition, a protein-protein interaction network was created to illustrate the interactions of TRIM28 with other proteins. The prognostic value of TRIM28 in patients with BC was investigated using the Kaplan-Meier Plotter database, which revealed that high expression of TRIM28 is a predictor of poor prognosis in patients with BC. In conclusion, the results of the present study indicate that TRIM28 provides a survival advantage to patients with BC and is a novel prognostic biomarker, in addition to being a therapeutic target for the treatment of BC.

Prognostic impact of EGFR and cytokeratin 5/6 immunohistochemical expression in triple-negative breast cancer

Triple-negative breast cancer (TNBC) has an aggressive behavior and limited therapeutic options due to lack of targeted therapy. We aimed in this study to assess the immunohistochemical expression of EGFR and cytokeratin 5/6 and their ability to predict survival and response to neoadjuvant chemotherapy (NAC) among triple-negative breast cancer patients. Thirty-five cases with TNBC were studied by immunohistochemistry for EGFR and CK5/6 expression. Data on overall survival (OS), disease-free survival (DFS) and response to NAC were collected. The resulted data were statistically analyzed. Invasive carcinoma of no special type (NST) was the predominant histopathological type (80%). The commonest histological grade was grade II-III (88.6%). About 57.1% of TNBC cases were CK5/6-positive, and 71.4% were EGFR-positive. EGFR expression showed a significant association with tumor grade and axillary lymph node metastasis (p=0.006, 0.016 respectively). EGFR expression was related to unfavorable response to NAC (p=0.036), poor OS (p=0.002) and poor DFS (p=0.003). CK5/6 expression showed a significant association with tumor grade, unfavorable response to NAC, poor OS & DFS (p=0.007, 0.048, <0.001, 0.043 respectively). Immunohistochemical expression of EGFR and/or CK5/6 showed a high significant association with an unfavorable response to NAC, poor DFS &OS (p=0.010, 0.012, 0.030 respectively).

CONCLUSIONS

EGFR and CK5/6 are adverse prognostic markers in TNBC. EGFR and CK5/6 expression could serve as biomarkers for identifying TNBC patients with poor survival that are unlikely to benefit from neoadjuvant chemotherapy. So, targeted therapy against EGFR may be a hopeful therapy for TNBC with NAC resistance.

The paradoxical functions of EGFR during breast cancer progression

The epidermal growth factor receptor (EGFR) is one of the most well-studied signaling pathways in cancer progression. As a result, numerous therapeutics including small-molecule inhibitors and monoclonal antibodies have been developed to target this critical oncogenic driver. Several of these EGFR inhibitors (EGFRi) have been evaluated in metastatic breast cancer, as high-level EGFR expression in primary tumors correlates with the highly aggressive basal-like phenotype and predicts for poor patient prognosis. Surprisingly, these trials have been unanimously unsuccessful at improving patient outcomes. Numerous factors, such as lack of proper patient selection may have contributed to the failure of these trials. However, recent findings suggest that there are fundamental changes in EGFR signaling that take place during primary tumor invasion, dissemination and ultimate metastasis of breast cancer cells. Herein, we review the outcomes of EGFR-targeted clinical trials in breast cancer and explore our current understanding of EGFR signaling within primary mammary tumors and how these events are altered in the metastatic setting. Overall, we put forth the hypothesis that fundamental changes in EGFR signaling between primary and metastatic tumors, a process we term the 'EGFR paradox,' contribute to the clinically observed inherent resistance to EGFRi. Furthermore, this hypothesis introduces the possibility of utilizing EGFR agonism as a potential therapeutic approach for the treatment of metastatic breast cancer.

Loss of monocyte chemoattractant protein-1 expression delays mammary tumorigenesis and reduces localized inflammation in the C3(1)/SV40Tag triple negative breast cancer model

Monocyte chemoattractant protein 1 (MCP-1) has been implicated as a major modulator in the progression of mammary tumorigenesis, largely due to its ability to recruit macrophages to the tumor microenvironment. Macrophages are key mediators in the connection between inflammation and cancer progression and have been shown to play an important role in tumorigenesis. Thus, MCP-1 may be a potential therapeutic target in inflammatory and difficult-to-treat cancers such as triple negative breast cancer (TNBC). We examined the effect of MCP-1 depletion on mammary tumorigenesis in a model of TNBC. Tumor measurements were conducted weekly (until 22 weeks of age) and at sacrifice (23 weeks of age) in female C3(1)/SV40Tag and C3(1)/SV40Tag MCP-1 deficient mice to determine tumor numbers and tumorvolumes. Histopathological scoring was performed at 12 weeks of age and 23 weeks of age. Gene expression of macrophage markers and inflammatory mediators were measured in the mammary gland and tumor microenvironment at sacrifice. As expected, MCP-1 depletion resulted in decreased tumorigenesis, indicated by reduced primary tumor volume and multiplicity, and a delay in tumor progression represented by histopathological scoring (12 weeks of age). Deficiency in MCP-1 significantly downregulated expression of macrophage markers in the mammary gland (Mertk and CD64) and the tumor microenvironment (CD64), and also reduced expression of inflammatory cytokines in the mammary gland (TNFα and IL-1β) and the tumor microenvironment (IL-6). These data support the hypothesis that MCP-1 expression contributes to increased tumorigenesis in a model of TNBC via recruitment of macrophages and subsequent increase in inflammatory mediators.

Efficacy of carboplatin-based preoperative chemotherapy for triple-negative breast cancer. A meta-analysis of randomized controlled trials

Objectives:

To evaluate the efficacy and safety of carboplatin-based preoperative chemotherapy in triple-negative breast cancer patients (TNBC).

Methods:

PubMed, EMBASE, the Web of Science, the Cochrane Library, major clinical trial registries, and abstract collections from major international meetings were systematically searched for relevant randomized controlled trials. Endpoints included rates of pathologic complete response (pCR), overall response (ORR), breast-conserving surgery (BCS) and toxicity. Pooled relative risk (RR) was calculated for each endpoint using a fixed- or random-effect model depending on the heterogeneity among included studies.

Results:

A total of 5 randomized controlled trials involving 1007 patients were included in the meta-analysis. Carboplatin-based chemotherapy was associated with a pooled pCR rate of 53.3%, which was significantly higher than the rate associated with non-carboplatin therapy (37.8%, RR: 1.41, 95% confidence interval [CI]: 1.23 to 1.62, p<0.00001). Compared with non-carboplatin therapy (48.1%), carboplatin-based chemotherapy increased BCS rate (59.7%, RR: 1.24, 95% CI: 1.06 to 1.46, p=0.007). Carboplatin-based chemotherapy was associated with similar ORR as non-carboplatin therapy. Carboplatin-based chemotherapy was associated with higher incidence of grade 3 or 4 anemia, neutropenia, febrile neutropenia, and thrombocytopenia than non-carboplatin therapy, while the 2 regimens were associated with similar incidence of fatigue, leucopenia, and nausea/vomiting.

Conclusion:

The available evidence suggests that carboplatin-based preoperative chemotherapy is associated with significantly better pCR and BCS rates than non-carboplatin-based therapy in TNBC patients.

Growth hormone-releasing hormone induced transactivation of epidermal growth factor receptor in human triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is a subset of breast cancers which is negative for expression of estrogen and progesterone receptors and human epidermal growth factor receptor-2 (HER2). Chemotherapy is currently the only form of treatment for women with TNBC. Growth hormone-releasing hormone (GHRH) and epidermal growth factor (EGF) are autocrine/paracrine growth factors in breast cancer and a substantial proportion of TNBC expresses receptors for GHRH and EGF. The aim of this study was to evaluate the interrelationship between both these signaling pathways in MDA-MB-468 human TNBC cells. We evaluated by Western blot assays the effect of GHRH on transactivation of EGF receptor (EGFR) as well as the elements implicated. We assessed the effect of GHRH on migration capability of MDA-MB-468 cells as well as the involvement of EGFR in this process by means of wound-healing assays. Our findings demonstrate that in MDA-MB-468 cells the stimulatory activity of GHRH on tyrosine phosphorylation of EGFR is exerted by two different molecular mechanisms: i) through GHRH receptors, GHRH stimulates a ligand-independent activation of EGFR involving at least cAMP/PKA and Src family signaling pathways; ii) GHRH also stimulates a ligand-dependent activation of EGFR implicating an extracellular pathway with an important role for metalloproteinases. The cross-talk between EGFR and GHRHR may be impeded by combining drugs acting upon GHRH receptors and EGFR family members. This combination of GHRH receptors antagonists with inhibitors of EGFR signalling could enhance the efficacy of both types of agents as well as reduce their doses increasing therapeutic benefits in management of human breast cancer.

Progress in the clinical detection of heterogeneity in breast cancer

Breast cancer is currently the most common form of cancer and the second‐leading cause of death from cancer in women. Though considerable progress has been made in the treatment of breast cancer, the heterogeneity of tumors (both inter‐ and intratumor) remains a considerable diagnostic and prognostic challenge. From clinical observation to genetic mutations, the history of understanding the heterogeneity of breast cancer is lengthy and detailed. Effectively detecting heterogeneity in breast cancer is important during treatment. Various methods of depicting this heterogeneity are now available and include genetic, pathologic, and imaging analysis. These methods allow characterization of the heterogeneity of breast cancer on a genetic level, providing greater insight during the process of establishing an effective therapeutic plan. This study reviews how the understanding of tumor heterogeneity in breast cancer evolved, and further summarizes recent advances in the detection and monitoring of this heterogeneity in patients with breast cancer.

Pathological Characteristics of Triple-Negative Breast Cancer at Main Referral Teaching Hospital, April 2014 to April 2015, Tehran, Iran

Background: Triple-negative breast cancers (TNBC) are defined as breast cancers with lack of estrogen and progesterone receptors and no overexpression of human epidermal growth factor receptor 2 (HER2). This study was performed to determine the frequency and pathologic features of TNBC in Iranian patients. Subjects and Methods: This cross-sectional study was performed on patients with breast cancer who referred to Cancer Institute, affiliated to Tehran University of Medical Sciences, from April 2014 to April 2015. Data about the demographics, the status of gene receptors and the pathologic features were extracted from patients' records. Results: Of 214 pathology samples of patients with malignant breast cancer, TNBCs account for 14% of cases. The mean age in N-TNBC group was 50 ± 12 years. Significant difference was seen between the age of two groups (p=0.03). No significant difference was observed regarding the number of involved lymph nodes between two groups (p=0.058). Presence of vascular and nerve invasion and involvement of surgical margins at the time of diagnosis were significantly more frequent in TNBC group comparing with N-TNBC. Grade III of histologic and nuclear grading was significantly more common in TNBC. Conclusion: TNBC group was significantly associated with higher grade, higher mitotic indices and higher rate of P53 positivity and higher level of Ki-67 at the time of diagnosis. High grade breast cancers are more seen in TNBC. The presence of aforementioned characteristics in a patient highlights the need for evaluating TNBC biomarkers to better predict prognosis and consider appropriate treatment.

Triple-negative breast cancer: advancements in characterization and treatment approach

PURPOSE OF REVIEW

Triple-negative breast cancer (TNBC) comprises 15-20% of all breast cancer and is defined by the lack of estrogen and progesterone receptor expression and absence of human epidermal growth factor receptor 2 amplification. Compared with patients with hormone receptor positive or Her-2 positive breast cancer, patients with TNBC are more commonly young (age <50 years), African-American and have a higher incidence of BRCA1/2 mutations. The clinical course is frequently characterized by early relapse and poor overall survival. The TNBC phenotype is impervious to therapies commonly used in other breast cancer subtypes, including hormonal therapy and Her-2 receptor antagonism. Cytotoxic chemotherapy remains the only approved treatment. With its aggressive clinical course and paucity of effective treatment options, TNBC represents an unmet clinical need. This review will focus on updates of the biologic underpinnings of TNBC and the associated treatment advances.

RECENT FINDINGS

Numerous advancements have been made toward understanding the biologic framework of TNBC. Gene expression profiling has revealed six clinically relevant subsets of TNBC. Further study has demonstrated a portion of TNBC exhibits a strong immune gene signature. Lastly, it is now appreciated that a subgroup of sporadic TNBC shares biologic characteristics with BRCA1/2-mutated breast cancer, notably homologous repair deficiency. Recent studies focus on incorporation of platinum salts and new combinations of conventional chemotherapeutic agents. Targeted agents, including poly-ADP ribose polymerase inhibitors, antiangiogenic agents, phosphoinositide 3-kinase (PI3K) pathway inhibitors, and androgen antagonist are also being evaluated. Most recently, checkpoint inhibitors have demonstrated a modest degree of activity in a subset of TNBC.

SUMMARY

These discoveries are informing novel treatment paradigms and identification of correlative biomarkers in TNBC. Improved understanding of the biologic heterogeneity of TNBC is allowing for a more effective and individualized approach to treatment.

Triple-Negative Breast Cancer: A Comprehensive Study of Clinical, Histomorphological, and Immunohistochemical Features in Indian Patients

Triple-negative breast cancers (TNBCs) are characterized by negative expression for estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptors. Although the majority of basal-like breast cancers (BLBCs) diagnosed based on gene expression profiling belong to the TNBC group, both entities are not synonymous. Core BLBCs are TNBCs, which are positive for basal cytokeratin (CK) and/or epidermal growth factor receptor (EGFR). We aimed to study and correlate a TNBC cohort for various histomorphological features and immunohistochemical (IHC) profile in Indian patients. We studied 205 naïve TNBCs for histopathological features, which were further evaluated for basal CKs-namely, CK5/6, CK14, CK17-and EGFR expression to classify them as core BLBCs, using criteria of any basal CK and/or EGFR positivity and 7-negative phenotype (7NP). Among 205 TNBCs, 91% of cases were core BLBCs, and absence of ductal carcinoma in situ (DCIS) was significantly associated ( P = .014) with core BLBC. Geographic necrosis was correlated with expression of CK17 ( P = .002) and EGFR ( P = .038). A ribbon-like trabecular pattern and absence of DCIS were associated with CK17 ( P = .0002 and P = .043, respectively) and CK14 ( P = .04 and P = .0008, respectively). TNBC is a heterogeneous subgroup with adverse clinicopathological features, and many of them show significant correlation with basal CKs. TNBCs cannot be classified as core BLBC or 7NP based on morphological features, except absence of DCIS. However, this study illustrates the heterogeneity in TNBCs on the basis of IHC markers.

High prevalence and predominance of BRCA1 germline mutations in Pakistani triple-negative breast cancer patients

BACKGROUND

Women harboring BRCA1/2 germline mutations have high lifetime risk of developing breast/ovarian cancer. The recommendation to pursue BRCA1/2 testing is based on patient's family history of breast/ovarian cancer, age of disease-onset and/or pathologic parameters of breast tumors. Here, we investigated if diagnosis of triple-negative breast cancer (TNBC) independently increases risk of carrying a BRCA1/2 mutation in Pakistan.

METHODS

Five hundred and twenty-three breast cancer patients including 237 diagnosed ≤ 30 years of age and 286 with a family history of breast/ovarian cancer were screened for BRCA1/2 small-range mutations and large genomic rearrangements. Immunohistochemical analyses were performed at one center. Univariate and multiple logistic regression models were used to investigate possible differences in prevalence of BRCA1/2 mutations according to patient and tumor characteristics.

RESULTS

Thirty-seven percent of patients presented with TNBC. The prevalence of BRCA1 mutations was higher in patients with TNBC than non-TNBC (37 % vs. 10 %, P < 0.0001). 1 % of TNBC patients were observed to have BRCA2 mutations. Subgroup analyses revealed a larger proportion of BRCA1 mutations in TNBC than non-TNBC among patients 1) diagnosed at early-age with no family history of breast/ovarian cancer (14 % vs. 5 %, P = 0.03), 2) diagnosed at early-age irrespective of family history (28 % vs. 11 %, P = 0.0003), 3) had a family history of breast cancer (49 % vs. 12 %, P < 0.0001), and 4) those with family history of breast and ovarian cancer (81 % vs. 28 %, P = 0.0005). TNBC patients harboring BRCA1 mutations were diagnosed at a later age than non-carriers (median age at diagnosis: 30 years (range 22-53) vs. 28 years (range 18-67), P = 0.002). The association between TNBC status and presence of BRCA1 mutations was independent of the simultaneous consideration of family phenotype, tumor histology and grade in a multiple logistic regression model (Ratio of the probability of carrying BRCA1/2 mutations for TNBC vs. non-TNBC 4.23; 95 % CI 2.50-7.14; P < 0.0001).

CONCLUSION

Genetic BRCA1 testing should be considered for Pakistani women diagnosed with TNBC.

Pretreatment TG/HDL-C Ratio Is Superior to Triacylglycerol Level as an Independent Prognostic Factor for the Survival of Triple Negative Breast Cancer Patients

Purpose: Previous studies have reported that the triacylglycerol (TG) level and high-density lipoprotein cholesterol (HDL-C) are connected with breast cancer. However, the prognostic utility of the TG level and the TG/HDL-C ratio (THR) as conventional biomarkers in patients with triple negative breast cancer (TNBC) has not been elucidated. In this research, we investigate and compare the predictive value of the pretreatment serum TG level and THR in TNBC patients.

Methods: We evaluated 221 patients with TNBC who had pretreatment conventional blood biochemical examinations and calculated the THR. Univariate and multivariate logistic regression analyses were used to assess the effect of the TG level and the THR on overall survival (OS) and disease-free survival (DFS).

Results: The optimal cutoff values of the TG level and the THR were determined to be 0.935 mmol/L and 0.600, respectively. As shown in a Kaplan-Meier analysis, TNBC patients with a high TG level and THR had shorter OS and DFS than patients in the low-level groups (p < 0.05). The multivariate analysis suggested that the pretreatment THR level is an independent prognostic factor of OS (HR: 1.935; 95%CI: 1.032-3.629; p = 0.040) in TNBC patients.

Conclusions: In conclusion, our data indicate that a high THR is an independent predictor and is superior to the TG level for predicting poor clinical outcomes in TNBC patients.

[Non-metastatic triple-negative breast cancer in 2016: Definitions and management]

Triple-negative breast cancer (TN), as defined by the triple negativity in immunohistochemistry: the absence of estrogen receptor, progesterone receptor and the absence of overexpression or amplification of HER2, corresponds to 15 % of invasive breast cancers. This is a very heterogeneous group of tumors both at the genomic and transcriptomic level and at morphological, clinical and prognostic level. Although there are some good prognosis forms, the majority of TN tumors is characterized by a poor prognosis with a greater frequency of visceral metastases and a maximum risk of relapse in the first two years after diagnosis. Systemic adjuvant treatment with chemotherapy is almost always indicated. The surgical treatment and radiotherapy treatment should be comparable to the other subtypes and obey the same rules of oncologic surgery. TN tumors are not associated with a higher risk of locoregional relapse after conservative treatment and adjuvant radiotherapy. Optimization of systemic therapies is currently and for the last decade a challenge. A number of targeted therapies and efficiency biomarkers identification of these targeted therapies is essential to allow significant progress in optimizing systemic therapy for these tumors.

Do platinum salts fit all triple negative breast cancers?

Triple-negative breast cancer (TNBC) is an aggressive disease with limited treatment options and poor prognosis once metastatic. Pre-clinical and clinical data suggest that TNBC could be more sensitive to platinum-based chemotherapy, especially among BRCA1/2-mutated patients. In recent years, several randomised trials have been conducted to evaluate platinum efficacy in both early-stage and advanced TNBC, with conflicting results especially for long-term outcomes. Experimental studies are now focusing on identifying biomarkers of response to help selecting patients who may benefit most from platinum-based therapies, including BRCA1/2 mutational status and genomic instability signatures (such as HRD-LOH or HRD-LST scores). A standard therapy for TNBC is still missing and platinum-based regimens represent an emerging therapeutic option for selected patients with a defect in the homologous recombination repair system. The identification of these patients through validated biomarker assays will be crucial to optimize the use of currently approved agents in TNBC.

Identification of epidermal growth factor receptor and its inhibitory microRNA141 as novel targets of Krüppel-like factor 8 in breast cancer

Krüppel-like factor 8 (KLF8) is a dual transcriptional factor critical for breast cancer progression. Epidermal growth factor receptor (EGFR) is frequently overexpressed in aggressive such as triple-negative breast cancer and associated with poor clinical outcomes. Here we report a novel KLF8-EGFR signaling axis in breast cancer. We identified a highly correlated co-overexpression between KLF8 and EGFR in invasive breast cancer cells and patient tumor samples. Overexpression of KLF8 in the non-tumorigenic MCF-10A cells induced the expression of EGFR, whereas knockdown of KLF8 from the MDA-MB-231 cells decreased it. Promoter activation and binding assays indicated that KLF8 promotes the EGFR expression by directly binding its gene promoter. We also revealed that KLF8 directly represses the promoter of miR141 and miR141 targets the 3′-untranslational region of EGFR transcript to inhibit EGFR translation. Treatment with the EGFR inhibitor AG1478 or overexpression of miR141 blocked the activity of ERK downstream of EGFR and inhibited KLF8-depndent cell invasiveness, proliferation and viability in cell culture and invasive growth and lung metastasis in nude mice. Conversely, overexpression of an inhibitory sponge of miR141 led to the opposite phenotypes. Taken together, these findings demonstrate a novel KLF8 to miR141/EGFR signaling pathway potentially crucial for breast cancer malignancy.

Coexistent Loss of the Expressions of BRCA1 and p53 Predicts Poor Prognosis in Triple-Negative Breast Cancer

BACKGROUND

To investigate the prognostic significance of altered breast cancer susceptibility gene 1 (BRCA1) and p53 expression in triple-negative breast cancer (TNBC).

METHODS

Immunohistochemical expression of BRCA1 and p53 was examined in the tumor tissues of 465 TNBC cases and relations were sought with clinicopathological features and patient survival.

RESULTS

Loss of BRCA1 expression was found in 29.5% (137/465) of TNBCs. Positive expression of p53 was observed in 49.9% (232/465). Patients with loss of BRCA1 expression had a tendency to have higher rate of lymph node metastasis (p = 0.075). An association between p53 expression and high histological grade was observed (p = 0.039). TNBC patients with loss of BRCA1 expression had a tendency to have poorer overall survival (OS) than those positive for BRCA1 (p = 0.09). TNBC patients with positive p53 expression showed better OS than those with p53 negativity (p = 0.001). In terms of combined expression patterns, significantly poorer overall survival (OS) was observed for BRCA1-negative/p53-negative TNBCs and best OS for BRCA1-positive/p53-positive TNBCs (p = 0.005).

CONCLUSIONS

Combined expression patterns of BRCA1 and p53 could serve as useful prognostic markers in TNBC.

Outcome of pN0 Triple-Negative Breast Cancer with or without Lymph Node Irradiation: A Single Institution Experience

The optimal management of patients with pathologically node-negative triple-negative breast cancer (pN0 TNBC) remains unclear. We hypothesized that lymph node irradiation (LNI; internal mammary chain/periclavicular irradiation) had an impact on outcomes of pN0 TNBC. A cohort of 126 consecutive patients with pN0 TNBC treated between 2007 and 2010 at a single institute were included. All radiotherapy (breast/chest wall, ±LNI) was delivered adjuvantly, following completion of surgery ± chemotherapy. Tumors were reviewed and histologic features were described. Tissue microarrays were constructed and tumors were assessed by immunohistochemistry using antibodies against ER, PR, HER2, Ki-67, cytokeratins 5/6, 14, epidermal growth factor receptor and androgen receptor. Patients were divided into two groups for statistical analysis: LNI (LNI+) or no LNI (LNI-). We focused on disease-free survival (DFS), metastasis-free survival (MFS), and overall survival (OS). Fifty-seven and 69 patients received or not LNI, respectively. Median age was 52 (range [25-76]) and 55 (range [29-79]) in LNI+ and LNI- group (p = 0.23). LNI was associated with larger tumors (p = 0.033), central/internal tumors (33 versus 4, p < 0.01) and more chemotherapy (86% versus 59.4% p < 0.01). The median follow-up was 53.5 months. The rate of first regional relapse (associated or not with distant relapse) was low in both groups. There was no difference in 4-year DFS (82.2% versus 89.9%; p = 0.266), MFS (87.0% versus 91.1%; p = 0.286) and OS (85.8% versus 89.9%; p = 0.322) between LNI+ and LNI- group, respectively. In univariate analysis, only clinical size (T >10 mm versus ≤10 mm), histologic size (pT >10 mm versus ≤10 mm) and grade 3 (versus grade 2) were found to be significantly associated with shorter DFS. Omission of LNI in patients with pN0 TNBC does not seem to result in poorer outcome. Further studies are needed to specifically evaluate LNI in pN0 TNBC with histologic grade 3 and/or (p)T >10 mm.

Loss of RAB1B promotes triple-negative breast cancer metastasis by activating TGF-β/SMAD signaling

Triple-negative breast cancer (TNBC) is a highly aggressive tumor subtype associated with a poor prognosis. The mechanism involved in TNBC progression remains largely unknown. To date, there are no effective therapeutic targets for this tumor subtype. In this study, by performing quantitative proteomic analyses in highly metastatic and parental breast cancer cell line, we found that RAB1B, a member of the RAS oncogene family, was significantly down-regulated in highly metastatic breast cancer cells. Moreover, down-regulation of RAB1B was also found to promote the proliferation and migration of TNBC cells in vitro and in vivo. Mechanistically, loss of RAB1B resulted in elevated expression of TGF-β receptor 1 (TβR1) through decreased degradation of ubiquitin, increased levels of phosphorylated SMAD3 and TGF-β-induced epithelial-mesenchymal transition (EMT). Furthermore, low RAB1B expression correlated with poor prognosis in breast cancer patients. Taken together, our findings reveal that RAB1B acts as a metastasis suppressor in TNBC by regulating the TGF-β/SMAD signaling pathway and RAB1B may serve as a novel biomarker of prognosis and the response to anti-tumor therapeutics for patients with TNBC.

Breed- and age-related differences in canine mammary tumors

Triple-negative breast cancer is a type of breast cancer that does not express the genes for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2). It is an important and clinically relevant condition as it has a poor prognosis and is difficult to treat. Basal-like triple-negative cancer is highly prevalent in both African-Americans and adolescents. We therefore examined whether such a cancer likewise occurs in specific breeds and age groups in dogs, focusing on basal-like triple-negative cancer in particular. In this study, 181 samples from dogs with malignant mammary carcinoma from the 5 most common breeds and 2 age groups in Korea were analyzed. Histological classification and molecular subtyping, including assessment of immunohistochemical findings, were carried out. Twenty-five of 28 (89.3%) triple-negative carcinomas were identified as basal-like triple-negative carcinomas. Analysis of associations of classified factors revealed that the shih tzu breed (9/25, 36.0%) and advanced-age (19/25, 76.0%) groups were characterized by higher prevalence of basal-like triple-negative tumors with diverse histological types and of a higher grade. These results suggest that breed- and age-related differences can be identified in canine mammary carcinoma and, notably, in the shih tzu breed and at older ages. Further investigation of these distinguishing characteristics of the shih tzu breed is warranted.

Differences in Multi-Modal Ultrasound Imaging between Triple Negative and Non-Triple Negative Breast Cancer

The objective of this study was to identify multi-modal ultrasound imaging parameters that could potentially help to differentiate between triple negative breast cancer (TNBC) and non-TNBC. Conventional ultrasonography, ultrasound strain elastography and 3-D ultrasound (3-D-US) findings from 50 TNBC and 179 non-TNBC patients were retrospectively reviewed. Immunohistochemical examination was used as the reference gold standard for cancer subtyping. Different ultrasound modalities were initially analyzed to define TNBC-related features. Subsequently, logistic regression analysis was applied to TNBC-related features to establish models for predicting TNBC. TNBCs often presented as micro-lobulated, markedly hypo-echoic masses with an abrupt interface (p = 0.015, 0.0015 and 0.004, compared with non-TNBCs, respectively) on conventional ultrasound, and showed a diminished retraction pattern phenomenon in the coronal plane (p = 0.035) on 3-D-US. Our findings suggest that B-mode ultrasound and 3-D-US in multi-modality ultrasonography could be a useful non-invasive technique for differentiating TNBCs from non-TNBCs.

c-Met and ERβ expression differences in basal-like and non-basal-like triple-negative breast cancer

Basal-like breast cancer (BLBC) and triple-negative breast cancer (TNBC) are two entities of breast cancer that share similar poor prognosis. Even though both cancers have overlaps, there are still some differences between those two types. It has been reported that the c-Met high expression was associated with poor prognosis not only in breast cancer but also in many other cancers. The role of ERβ in pathogenesis and treatment of breast cancer has remained controversial. In this study, we firstly distinguished basal-like from nonbasal-like cancer patients in TNBC patients using CK5/6 and EGFR as markers and next determined the relationship of basal-like breast cancer with c-Met or ERβ expression levels and prognosis in TNBC patients. One hundred twenty-seven patients who had been diagnosed with TNBC were enrolled. The clinical and pathological characteristics of the patients were recorded. The expression of EGFR, CK5/6, ERβ, and c-Met were evaluated with immunohistochemical methods using paraffin blocks. The median age of patients was 50.7 years. CK5/6 immunopositivity was 31.5 % (40/127), and EGFR was 40.2 % (51/127). Of the TNBC cases, 55.1 % (71/127) were positive for either CK5/6 or EGFR and were thus classified as basal-like breast cancer. C-Met (P < 0.001) and ERβ (P = 0.002) overexpression, small tumor sizes, a ductal subtype, and high-grade tumor were significantly correlated with BLBC. High c-Met expression was detected in 43.3 % patients. Metastatic lymph nodes and tumor size (>5 cm), which were both important prognostic predictors, were significantly associated with recurrence and mortality. BLBC typically demonstrates a unique profile. CK5/6 and EGFR expression combination indicates a higher basal-like phenotype possibility. The expression of c-Met and ERβ were significantly related to the basal-like phenotype. The classical markers, lymph node metastasis, and tumor size were found to have important prognostic value. However, high c-Met expression and basal-like phenotypes did not show a direct correlation with poor prognosis.

Prognostic analysis of triple-negative breast cancer patients treated with adjuvant chemotherapy of fluorouracil, epirubicin and cyclophosphamide

The aim of the present study was to investigate the association between the clinicopathological and demographic factors, and the survival time of patients with triple-negative breast cancer (TNBC) in China. The patients had received adjuvant chemotherapy consisting of 5-fluorouracil, epirubicin and cyclophosphamide (FEC; 500 mg/m² cyclophosphamide, day 1; 75 mg/m² epirubicin, day 1; 500 mg/m² 5-fluorouracil, days 1 and 8; every 3 weeks, for at least 4 cycles). The clinicopathological and demographic factors affecting the outcome of the patients with TNBC that received adjuvant FEC chemotherapy were evaluated. Within these variables, the overall survival (OS) and disease-free survival (DFS) times were analyzed using the log-rank test, which was constructed using the multivariate Cox proportional hazards regression model and Kaplan-Meier analysis. Additionally, Spearman's χ² test was used to analyze categorical variables. In the univariate statistical analysis, the significant risk factors for TNBC patient survival were the stage of disease and lymph node status, which were associated with the OS and DFS, and the total number of pregnancies, which was associated with the DFS. In the multivariate Cox proportional hazard model, lymph node status was an independent prognostic indicator of OS [P<0.001; hazard ratio (HR), 1.996; 95% confidence interval (CI), 1.465-2.720] and DFS (P<0.001; HR, 1.824; 95% CI, 1.315-2.531). By the Kaplan-Meier method, the stage of disease and lymph node status demonstrated a significant effect on OS and DFS. Patients with the lymph node status N3 and stage III disease possessed a poor prognosis and survival. An association between lymph node status and the tumor recurrence and mortality rate was identified. The area under the curves of the lymph node status for TNBC recurrence and mortality were 0.676 (P=0.002) and 0.685 (P=0.001), respectively. Additionally, the number of pregnancies was associated with tumor size, lymph node status and stages of disease. Lymph node status is an independent prognostic indicator of OS and DFS to TNBC patients with FEC adjuvant chemotherapy.

Beyond Axillary Lymph Node Metastasis, BMI and Menopausal Status Are Prognostic Determinants for Triple-Negative Breast Cancer Treated by Neoadjuvant Chemotherapy

Background

Triple-negative breast cancers (TNBC) are a specific subtype of breast cancers with a particularly poor prognosis. However, it is a very heterogeneous subgroup in terms of clinical behavior and sensitivity to systemic treatments. Thus, the identification of risk factors specifically associated with those tumors still represents a major challenge. A therapeutic strategy increasingly used for TNBC patients is neoadjuvant chemotherapy (NAC). Only a subset of patients achieves a pathologic complete response (pCR) after NAC and have a better outcome than patients with residual disease.

Purpose

The aim of this study is to identify clinical factors associated with the metastatic-free survival in TNBC patients who received NAC.

Methods

We analyzed 326 cT1-3N1-3M0 patients with ductal infiltrating TNBC treated by NAC. The survival analysis was performed using a Cox proportional hazard model to determine clinical features associated with prognosis on the whole TNBC dataset. In addition, we built a recursive partitioning tree in order to identify additional clinical features associated with prognosis in specific subgroups of TNBC patients.

Results

We identified the lymph node involvement after NAC as the only clinical feature significantly associated with a poor prognosis using a Cox multivariate model (HR = 3.89 [2.42–6.25], p<0.0001). Using our recursive partitioning tree, we were able to distinguish 5 subgroups of TNBC patients with different prognosis. For patients without lymph node involvement after NAC, obesity was significantly associated with a poor prognosis (HR = 2.64 [1.28–5.55]). As for patients with lymph node involvement after NAC, the pre-menopausal status in grade III tumors was associated with poor prognosis (HR = 9.68 [5.71–18.31]).

Conclusion

This study demonstrates that axillary lymph node status after NAC is the major prognostic factor for triple-negative breast cancers. Moreover, we identified body mass index and menopausal status as two other promising prognostic factors in this breast cancer subgroup. Using these clinical factors, we were able to classify TNBC patients in 5 subgroups, for which pre-menopausal patients with grade III tumors and lymph node involvement after NAC have the worse prognosis.

SSBP1 Suppresses TGFβ-Driven Epithelial-to-Mesenchymal Transition and Metastasis in Triple-Negative Breast Cancer by Regulating Mitochondrial Retrograde Signaling

Triple-negative breast cancer (TNBC) is a highly aggressive tumor subtype lacking effective prognostic indicators or therapeutic targets. Mitochondrial function is dysregulated frequently in cancer cells to allow for adaptation to a harsh tumor microenvironment. Targeting mitochondrial biogenesis and bioenergetics is, therefore, an attractive therapeutic strategy. In this study, we performed quantitative proteomic analyses in human parental and metastatic breast cancer cell lines to identify mitochondrial proteins involved in TNBC metastasis. We found that single-strand DNA-binding protein 1 (SSBP1) was downregulated in highly metastatic breast cancer cells. Moreover, SSBP1 downregulation promoted TNBC cell metastasis in vitro and in vivo. Mechanistically, SSBP1 loss decreased mitochondrial DNA copy number, thereby potentiating calcineurin-mediated mitochondrial retrograde signaling that induced c-Rel/p50 nuclear localization, activated TGFβ promoter activity, and TGFβ-driven epithelial-to-mesenchymal transition. Low SSBP1 expression correlated with tumor progression and poor prognosis in patients. Collectively, our findings identified SSBP1 as a novel metastasis suppressor and elucidated the mechanisms by which dysregulated mitochondrial signaling contributes to metastatic potential, providing potential new prognostic indicators for patients with TNBC.

Biomarkers in triple negative breast cancer: A review

Breast cancer is an intrinsically heterogeneous disease. In the world about 1 million cases of breast cancer are diagnosed annually and more than 170000 are triple-negative. Characteristic feature of triple negative breast cancer (TNBC) is that it lacks expression of oestrogen, progesterone and human epidermal growth factor receptor-2/neu receptors. They comprise 15%-20% of all breast cancers. We did a systematic review of PubMed and conference databases to identify studies published on biomarkers in TNBC. We included studies with biomarkers including: Epidermal growth factor receptor, vascular endothelial growth factor, c-Myc, C-kit and basal cytokeratins, Poly(ADP-ribose) polymerase-1, p53, tyrosinase kinases, m-TOR, heat and shock proteins and TOP-2A in TNBC. We also looked for studies published on synthetic lethality and inhibition of angiogenesis, growth, and survival pathways. TNBC is a complex disease subtype with many subclasses. Majority TNBC have a basal-like molecular phenotype by gene expression profiling. Their clinical and pathologic features overlap with hereditary BRCA1 related breast cancers. Management of these tumours is a challenge to the clinician because of its aggressive behaviour, poor outcome, and absence of targeted therapies. As the complexity of this disease is being simplified over time new targets are also being discovered for the treatment of this disease. There are many biomarkers in TNBC being used in clinical practice. Biomarkers may be useful as prognostic or predictive indicators as well as suggest possible targets for novel therapies. Many targeted agents are being studied for treatment of TNBC.

Triple Negative Breast Cancer versus Non-Triple Negative Breast Cancer Treated with Breast Conservation Surgery Followed by Radiotherapy: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this study was to compare the efficacy of breast conservation surgery (BCS) followed by radiotherapy (RT) in triple negative breast cancer (TNBC) versus non-TNBC.

METHODS

We searched the MEDLINE and EMBASE databases from inception through March 31, 2014, using search terms related to TNBC, BCS, and RT. Studies comparing the efficacy of BCS followed by RT in TNBC versus non-TNBC were reviewed.

RESULTS

5 studies including 2,922 non-TNBC and 510 TNBC cases were selected. The overall quality of included studies was deemed moderate to high. Compared with non-TNBC, the pooled relative risk of 5-year local relapse-free survival was 1.315 (95% confidence interval (CI) 0.967-1.789; p = 0.008) for TNBC, and that of 5-year overall survival, regional relapse-free survival, and distant metastasis-free survival was 1.929 (95% CI 1.392-2.674; p = 0.000), 3.052 (95% CI 1.629-5.715; p = 0.000), and 2.407 (95% CI 1.910-3.034; p = 0.000), respectively.

CONCLUSION

The local control rate of TNBC treated with BCS plus RT is similar to that of non-TNBC.

Liver Metastasis of a Triple-Negative Breast Cancer and Complete Remission for 5 Years After Treatment With Combined Bevacizumab/Paclitaxel/Carboplatin: Case Report and Review of the Literature

Triple-negative breast cancer (TNBC) is aggressive, with high risk of visceral metastasis and death. A substantial proportion of patients with TNBC is associated with BRCA mutations, implying that these tumors are sensitive to DNA-damaging agents. We report successful treatment of a metastatic TNBC in a woman with a BRCA2 germline mutation using combined bevacizumab/paclitaxel/carboplatin (BPC) therapy. The patient was pregnant and had liver metastases, and a complete clinical response was sustained for approximately 5 years. Mastectomy was performed during the 29th week of pregnancy, and the baby was later delivered by caesarean section. Subsequently, multiple metastases in both liver lobes were detected using computed tomography and magnetic resonance imaging and the patient was treated with a BPC regimen, which led to complete disappearance of metastatic lesions in the liver. No additional treatment was provided, and after 5 years the patient consented to direct sequencing of BRCA2 and a 6781delG mutation was identified. At the most recent (5-year) follow-up, the patient was alive with good quality of life and no evidence of metastases.This finding suggests that BPC therapy might be considered a good therapeutic option for the treatment of metastatic TNBC in a woman with a BRCA2 germline mutation.

The antitumorigenic function of EGFR in metastatic breast cancer is regulated by expression of Mig6

Numerous studies by our lab and others demonstrate that epidermal growth factor receptor (EGFR) plays critical roles in primary breast cancer (BC) initiation, growth and dissemination. However, clinical trials targeting EGFR function in BC have lead to disappointing results. In the current study we sought to identify the mechanisms responsible for this disparity by investigating the function of EGFR across the continuum of the metastatic cascade. We previously established that overexpression of EGFR is sufficient for formation of in situ primary tumors by otherwise nontransformed murine mammary gland cells. Induction of epithelial-mesenchymal transition (EMT) is sufficient to drive the metastasis of these EGFR-transformed tumors. Examining growth factor receptor expression across this and other models revealed a potent downregulation of EGFR through metastatic progression. Consistent with diminution of EGFR following EMT and metastasis EGF stimulation changes from a proliferative to an apoptotic response in in situ versus metastatic tumor cells, respectively. Furthermore, overexpression of EGFR in metastatic MDA-MB-231 BC cells promoted their antitumorigenic response to EGF in three dimensional (3D) metastatic outgrowth assays. In line with the paradoxical function of EGFR through EMT and metastasis we demonstrate that the EGFR inhibitory molecule, Mitogen Induced Gene-6 (Mig6), is tumor suppressive in in situ tumor cells. However, Mig6 expression is absolutely required for prevention of apoptosis and ultimate metastasis of MDA-MB-231 cells. Further understanding of the paradoxical function of EGFR between primary and metastatic tumors will be essential for application of its targeted molecular therapies in BC.

Comprehensive prognostic analysis in breast cancer integrating clinical, tumoral, micro-environmental and immunohistochemical criteria

Significant morphological, clinical and biological prognostic factors vary according to molecular subtypes of breast tumors, yet comprehensive analysis of such factors linked to survival in each group is lacking. Clinicopathological and micro-environmental criteria, estrogen (ER), progesterone (PR) receptors, HER2, Ki67, basal markers, CD24, CD44, ALDH1, BCL2, E-Cadherin and Trio were assessed in 1070 primary operable breast cancers from a single center according to five main molecular subtypes and associations with distant metastasis-free survival (DMFS) were examined. There were 682 (64 %) luminal A (LA), 166 (16 %) Luminal B HER2 negative (LBH−), 47 (4 %) Luminal B HER2 positive (LBH+), 108 (10 %) triple negative (TN) and 67 (6 %) HER2-enriched tumors (H2+). Median follow-up was 13.7 years. At 5 years, DMFS in LA (90 %) was better than in LBH− (80.9 %), hazard ratio (HR) = 2.22 [1.44–3.43] P < 0.001; LBH+ (74.5 %), HR = 3.14 [1.69–5.84] P < 0.001, TN (71.5 %) HR = 3.63 [2.34–5.63], P < 0.001; and H2+ (65.2 %), HR = 4.69 [2.90–7.59], P < 0.001. In multivariable analysis, factors associated with shorter DMFS varied according to molecular subtype, with tumor size being associated with shorter DMFS in the LBH−, LBH+ and TN groups and the Rho GEF Trio and BCL2 phenotypes in TN tumors only. These findings help to define new clinicophenotypic models and to identify new therapeutic strategies in the specific molecular subgroups.

Prognostic effect analysis of molecular subtype on young breast cancer patients

OBJECTIVE

To make a prognostic effect analysis of molecular subtype on young breast cancer patients.

METHODS

Totally 187 cases of young breast cancer patients less than 40 years old treated in Obstetrics and Gynecology Hospital of Fudan University between June 2005 and June 2011 were included in our study. We described their clinical-pathological characteristics, disease-free survival (DFS) rate, and overall survival (OS) rate after a median follow-up period of 61 months. The factors associated with prognosis were also evaluated by univariate and multivariate analyses.

RESULTS

All patients were premenopausal, with an average age of 35.36±3.88 years old. The mean tumor size was 2.43±1.53 cm. Eighty-one cases had lymph node metastasis (43.3%), 126 cases had lymphovascular invasion (67.4%), and 125 cases had histological grade III (66.8%) disease. Twenty-seven cases (14.4%) were Luminal A subtype, 99 cases (52.9%) were Luminal B subtype, 29 cases (15.5%) were human epidermal growth factor receptor 2 (HER-2) overexpression subtype, while 32 cases (17.1%) were triple negative breast cancer (TNBC) subtype according to 2013 St Gallen expert consensus. One hundred and thirty-five cases underwent mastectomy whereas 52 cases had breast-conserving surgery. One hundred and seventy-eight cases underwent adjuvant or neoadjuvant chemotherapy. Recurrence or metastasis occurred in 29 cases, 13 of which died. The 5-year DFS and OS rates were 84% and 92%. Multivariate analysis showed that nodal status (P=0.041) and molecular subtype (P=0.037) were both independent prognostic factors of DFS, while nodal status (P=0.037) and TNBC subtype (P=0.048) were both independent prognostic factors of OS.

CONCLUSIONS

Molecular subtype is an independent prognostic factor of young breast cancer patients. TNBC has a high risk of relapse and death.

A Comparison of Clinical Features, Pathology and Outcomes in Various Subtypes of Breast Cancer in Indian Women

BACKGROUND

Breast cancer is often classified into subtypes using immunohistochemical markers. These subtypes have distinct biological behaviour. This study was conducted with the aim of estimating the distribution of various subtypes of breast cancer in Indian population based on immunohistochemistry markers and to determine the clinical features, pathology and outcomes of these subtypes of breast cancer.

MATERIALS AND METHODS

A retrospective study was undertaken and all patients of breast cancer over a 5 year period were included. These patients were divided into 4 subgroups depending on the presence or absence of immunohistochemical markers: i) Luminal A (ER/PR+, Her 2 neu-); ii) Luminal B (ER/PR+, Her 2 neu+); iii) Her 2 enriched (ER-/PR-, Her 2 neu+) and; iv) Triple negative (ER-, PR-, Her2 neu-). Clinical and pathological features and survival were compared between patients in the 4 subgroups.

RESULTS

Luminal A subgroup had majority of patients (43.8%). Patients in Luminal B, Her 2 enriched, and Triple negative subgroups were 14.8%, 16.1% and 25.3%. Median follow-up of patients was for 34 months. Luminal A subgroup patients were more likely to be postmenopausal and have smaller and lower grade (I/II) tumours with better survival (OS-91.06%). Patients in the Triple negative subgroup were more likely to be premenopausal (p-value 0.036, odds ratio 0.611, CI 0.394-0.949), have larger and higher grade (III) tumours with worse overall survival (OS-88.46%, odds ratio 1.32, 95%CI 0.602-2.39). Her 2 enriched group patients had bad prognostic features like larger size of tumour and higher grade of tumour and worst survival among all the subgroups (OS-85.07%, odds ratio 1.78, 95% CI 0.767-4.163). However, these outcomes were not statistically significant for the subgroups.

CONCLUSION

A retrospective study was undertaken of breast cancer patients in India, according to subtypes based on immunohistochemistry. Luminal A had prognostic features and survival which was better as compared to other subgroups (Luminal B, Her 2 enriched and Triple negative). Incidence of patients with Triple negative breast cancer was higher in the premenopausal period. Patients with Her 2 enriched breast cancer had the worst survival among all the subgroups.

What common biomarkers characterize a triple-negative profile in breast cancer?

Triple-negative breast cancers are not a homogeneous subgroup. There is substantial intra-subgroup diversity in tumor biology, prognosis and treatment sensitivity. Then, these triple-negative phenotype (TNP) groups, having specific features, can be again divided into subclasses based on an added immunohistochemical markers. The challenge in treating TNP breast cancers is that they are not responsive to antiestrogens or trastuzumab secondary to negative receptor status, and as a result have a poor prognosis. Therefore, the presence or absence of supplementary markers could help predict which therapies are best suited for patients based on the pattern that their disease markers show. In this review, we will recapitulate the major supplementary biomarkers related to triple-negative breast cancer, which could give new therapeutic options.

Mutational profiles in triple-negative breast cancer defined by ultradeep multigene sequencing show high rates of PI3K pathway alterations and clinically relevant entity subgroup specific differences

Mutational profiling of triple-negative breast cancer (TNBC) by whole exome sequencing (WES) yielded a landscape of genomic alterations in this tumor entity. However, the clinical significance of these findings remains enigmatic. Further, integration of WES in routine diagnostics using formalin-fixed paraffin-embedded (FFPE) material is currently not feasible.

Therefore, we designed and validated a breast cancer specific gene panel for semiconductor-based sequencing comprising 137 amplicons covering mutational hotspots in 44 genes and applied this panel on a cohort of 104 well-characterized FFPE TNBC with complete clinical follow-up.

TP53 mutations were present in more than 80% of cases. PI3K pathway alterations (29.8%) comprising mainly PIK3CA mutations (22.1%) but also mutations and/or amplifications/deletions in other PI3K-associated genes (7.7%) were far more frequently observed, when compared to WES data. Alterations in MAPK signaling genes (8.7%) and cell-cycle regulators (14.4%) were also frequent. Mutational profiles were linked to TNBC subgroups defined by morphology and immunohistochemistry. Alterations in cell-cycle pathway regulators were linked with better overall (p=0.053) but not disease free survival.

Taken together, we could demonstrate that breast cancer targeted hotspot sequencing is feasible in a routine setting and yields reliable and clinically meaningful results. Mutational spectra were linked to clinical and immunohistochemically defined parameters.

An overview of triple negative breast cancer for surgical oncologists

Triple negative breast cancers (TNBCs) represent a distinct subgroup of breast cancers with an immunohistochemical phenotype that is negative for oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). The aim of this article is to provide a broad overview of recent developments in the diagnosis and management of TNBC for surgical oncologists. This overview discusses the subtypes of TNBC and the relationship between this type of breast cancer and the BRCA1 gene. In addition, the article explores recent advances in the treatment of TNBC from a surgical, radiation, and medical oncology point of view. Lastly, evolving therapeutic strategies that have potential to enhance outcomes for patients with TNBC are also discussed.

Expression of HIF-1α and Markers of Angiogenesis Are Not Significantly Different in Triple Negative Breast Cancer Compared to Other Breast Cancer Molecular Subtypes: Implications for Future Therapy

INTRODUCTION

Triple negative breast cancer lacks estrogen, progesterone and epidermal growth factor receptors rendering it refractory to available targetedtherapies. TNBC is associated with central fibrosis and necrosis, both indicators of tumor hypoxia. Hypoxia inducible factor 1α is up-regulated under hypoxia and its expression is associated with induction of angiogenesis resulting in proliferation, aggressive tumor phenotype and metastasis. In this study we evaluate the potential use of HIF-1α as aTNBC-specific marker.

METHODS

62 TNBC, 64 HER2+, and 64 hormone-receptors positive breast cancer cases were evaluated for central fibrosis and necrosis, HIF-1α, HIF-1β, VEGFR3, CD31 expression and microvessel density. RNA extraction from paraffin-embedded samples, followed by quantitative real-time polymerase chain reaction (qRT-PCR) evaluation of HIF-1α and VEGF transcripts was performed on 54 cases (18 from each subtype).

RESULTS

HIF-1α protein was expressed in 35.5% TNBC, 45.3% HER2+and 25.0% ER+/PR+ (p = 0.055; χ2 test). PCRanalysis of subgroup of breast cancers, 84.2% expressed HIF-1α protein and its transcripts, while only 66.7% expressed VEGF transcripts simultaneously with the HIF-1α protein and its transcripts. Central fibrosis and necrosis was highest in TNBC (p = 0.015; χ2 test), while MVD was comparable among all groups (p = 0.928; χ2 test). VEGFR3 was highest in TNBC expressing HIF-1α. HIF-1β protein was expressed in 32.0% of HIF-1α(+), and in (44.3%) of HIF-1α(-) breast cancer cases (p = 0.033; χ2 test). Moreover, HIF-1α expression in cases with central fibrosis and necrosis was highest in the HER2+ followed by the TNBC (p = 0.156; χ2 test).

CONCLUSIONS

A proportion of TNBC express HIF-1α but not in a significantly different manner from other breast cancer subtypes. The potential of anti-HIF-1α targeted therapy is therefore not a candidate for exclusive use in TNBC, but should be considered in all breast cancers, especially in the setting of clinically aggressive or refractory disease.

Dual inhibition of EGFR and MET induces synthetic lethality in triple-negative breast cancer cells through downregulation of ribosomal protein S6

Triple-negative breast cancer (TNBC) exhibits innate resistance to the EGFR inhibition despite high level expression of EGFR. Recently, we found that the proliferation of basal-like (BL) subtype TNBC cells is synergistically inhibited by combination of EGFR and PI3K/AKT inhibitors. On the contrary, TNBC cells of mesenchymal stem-like (MSL) subtype are resistant to these combinations. To identify potential synthetic lethal interaction of compounds for treatment of MSL subtype TNBC cells, we performed MTT screening of MDA-MB-231 cells with a small library of receptor tyrosine kinase inhibitors (RTKIs) in the presence of gefitinib, an EGFR inhibitor. We identified MET inhibitors as potent RTKIs that caused synthetic lethality in combination with gefitinib in MDA-MB-231 cells. We demonstrated that combination of a MET inhibitor SU11274 with various EGFR inhibitors resulted in synergistic suppression of cell viability (in MTT assay) and cell survival (in colony formation assay) of MSL subtype TNBC cells. We further demonstrated that SU11274 alone induced G2 arrest and gefitinib/SU11274 combination sustained the SU11274-induced G2 arrest in these cells. In addition, SU11274/gefitinib combination synergistically reduced the level of ribosomal protein S6 (RPS6) in MSL subtype TNBC cells. In addition, knockdown of RPS6 itself, in both HS578T and MDA-MB-231, markedly reduced the proliferation of these cells. Taken together, our data suggest that dual targeting of EGFR and MET inhibits the proliferation of MSL subtype TNBC cells through down-regulation of RPS6.

Gamma secretase inhibitor enhances sensitivity to doxorubicin in MDA-MB-231 cells

Deregulated expression of molecular of the Notch signaling pathway is observed in malignant tumor. Notch signaling pathway is activated by a series of catalytic cleavage of the Notch receptor by gamma secretase. Gamma secretase inhibitor (GSI) have demonstrated clinical activity in patients with solid tumor. Triple negative breast cancer (TNBC) is related to poor prognosis and a high probability of lung and brain metastases. As first line therapy for TNBC, doxorubicin is partially effective in TNBC control. An understanding of the mechanisms for enhancing sensitivity to doxorubicin would be significant for future drug development. We hypothesized that a combination of cytotoxic chemotherapy doxorubicin to inhibit cell proliferation, together with GSI, would result in more effective outcome than either monotherapy alone. We treated MDA-MB-231 cell lines with doxorubicin and evaluated the monotherapy efficacy and in combination with GSI in both vitro and vivo. GSI-induced proliferation inhibition and apoptosis was achieved with an induction of PTEN and pro-apoptotic protein Bax expression and suppression of Notch-1, HES-1, CyclinD1 and anti-apoptotic protein Bcl-2. These results indicate that MDA-MB-231 cells are susceptible to a GSI, whether alone or in combination with doxorubicin, are correlated with changing of some surrogate marker. This study demonstrates practicability of combined use of GSI and doxorubicin, and together these results encourage new therapeutic method in triple negative breast cancer.

USP2 promotes cell migration and invasion in triple negative breast cancer cell lines

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is often associated with a poor prognosis. The aim of our study was to identify biomarkers predictive of TNBC progression. Primary TNBC breast tissue samples including four with metastasis and six without metastasis were subjected to Affymetrix GeneChip® analysis (human genome U133). Ubiquitin-specific protease 2 (USP2) was identified as an upregulated gene in the metastatic group, and its expression was analyzed by immunohistochemistry in 121 primary breast cancers, 13 paired normal tissues, and 13 paired metastatic lesions. Survival analysis was performed using the log-rank test and Cox regression hazard model. Matrigel migration and invasion assays in USP2-silenced and USP2-overexpressed breast cancer cell lines were used to investigate the mechanisms of USP2 in vitro. Positive immunostaining for USP2 was detected in breast tumors and was correlated with estrogen receptor (ER) and progesterone receptor (PR) statuses and TNBC subtype. USP2 was overexpressed in distant metastatic lesions compared with primary breast cancers. Survival analyses demonstrated that positive USP2 is a poor prognostic factor for disease-free survival. Silencing of USP2 expression decreased migration and invasion in LM2-4175 and SCP46 cells in association with the downregulation of matrix metalloproteinase-2 (MMP2) expression, whereas overexpression of USP2 in MDA-MB-468 and MDA-MB-231 cells enhanced migration and invasion and upregulated the expression of MMP2. The present study showed that USP2 expression is associated with TNBC cell line's invasiveness and poor survival of breast cancer patients and may serve as a prognostic biomarker and therapeutic target for TNBC.

microRNA expression profiling identifies a four microRNA signature as a novel diagnostic and prognostic biomarker in triple negative breast cancers

Triple Negative Breast Cancers (TNBC) is a heterogeneous disease at the molecular and clinical level with poor outcome. Molecular subclassification of TNBCs is essential for optimal use of current therapies and for development of new drugs. microRNAs (miRNA) are widely recognized as key players in cancer progression and drug resistance; investigation of their involvement in a TNBC cohort may reveal biomarkers for diagnosis and prognosis of TNBC. Here we stratified a large TNBC cohort into Core Basal (CB, EGFR and/or CK5, 6 positive) and five negative (5NP) if all markers are negative. We determined the complete miRNA expression profile and found a subset of miRNAs specifically deregulated in the two subclasses.

We identified a 4-miRNA signature given by miR-155, miR-493, miR-30e and miR-27a expression levels, that allowed subdivision of TNBCs not only into CB and 5NP subgroups (sensitivity 0.75 and specificity 0.56; AUC=0.74) but also into high risk and low risk groups. We tested the diagnostic and prognostic performances of both the 5 IHC marker panel and the 4-miRNA expression signatures, which clearly identify worse outcome patients in the treated and untreated subcohorts. Both signatures have diagnostic and prognostic value, predicting outcomes of patient treatment with the two most commonly used chemotherapy regimens in TNBC: anthracycline or anthracycline plus taxanes. Further investigation of the patients' overall survival treated with these regimens show that regardless of IHC group subdivision, taxanes addition did not benefit patients, possibly due to miRNA driven taxanes resistance. TNBC subclassification based on the 5 IHC markers and on the miR-155, miR-493, miR-30e, miR-27a expression levels are powerful diagnostic tools. Treatment choice and new drug development should consider this new subtyping and miRNA expression signature in planning low toxicity, maximum efficacy therapies.

Estrogen receptor β: putting a positive into triple negative breast cancer?

Abstract ERβ was discovered over 15 years ago, yet the initial expectancy that this protein could have therapeutic use has ebbed, because of the complexity surrounding its function and significance in breast cancer. It has become apparent that its functional role and prognostic significance in breast cancer may depend on a number of factors, such as co-expression with ERα, presence of various isoforms (ERβ1, -2 and -5 in breast cancer), post-transcriptional modifications and cellular location. Interestingly, ERβ1 is often expressed in triple negative breast cancer (TNBC), a more aggressive type of breast cancer with limited treatment options because of the lack of expression of a recognised biological target. Furthermore, clinical data has demonstrated a clear correlation between ERβ1 positivity and improved disease-free and overall survival in those patients treated with tamoxifen. This suggests ERβ1 may be worth considering as a potential therapeutic target, particularly in TNBC.

Mesothelin expression in triple negative breast carcinomas correlates significantly with basal-like phenotype, distant metastases and decreased survival

Mesothelin is a cell surface associated antigen expressed on mesothelial cells and in some malignant neoplasms. Mesothelin-targeted therapies are in phase I/II clinical trials. The clinicopathologic and prognostic significance of mesothelin expression in triple negative breast carcinomas (TNBC) has not been fully assessed. We evaluated the expression of mesothelin and of basal markers in tissue microarrays of 226 TNBC and 88 non-TNBC and assessed the clinicopathologic features of mesothelin-expressing breast carcinomas. Furthermore, we investigated the impact of mesothelin expression on the disease-free and overall survival of patients with TNBC. We found that mesothelin expression is significantly more frequent in TNBC than in non-TNBC (36% vs 16%, respectively; p = 0.0006), and is significantly correlated with immunoreactivity for basal keratins, but not for EGFR. Mesothelin-positive and mesothelin-negative TNBC were not significantly different by patients’ race, tumor size, histologic grade, tumor subtype, lymphovascular invasion and lymph node metastases. Patients with mesothelin-positive TNBC were older than patients with mesothelin-negative TNBC, developed more distant metastases with a shorter interval, and had significantly lower overall and disease-free survival. Based on our results, patients with mesothelin-positive TNBC could benefit from mesothelin-targeted therapies.

Pathologic diagnosis, immunohistochemistry, multigene assays and breast cancer treatment: progress toward "precision" cancer therapy

Clinical decisions regarding the suitability of adjuvant systemic therapy for individual patients with breast cancer depends on comprehensive assessment of the underlying biology of each patient's tumor. The previous clinical-pathologic paradigm for treatment, which had been used for decades, now has been augmented by significant advances in molecular analysis of breast tumor tissue samples. Molecular testing has the potential to understand better both tumor biology and clinical behavior, which enables more appropriate therapy choices to be made. We review the rapid evolution in profiling breast cancer tissues, and discuss the current evidence for clinical use of this information and how the emerging molecular paradigm can be integrated into the clinical-pathologic context as we progress toward "precision" therapy for patients with breast cancer and other solid tumors.