Molecular stratification within triple-negative breast cancer subtypes

AbstractTriple-negative breast cancer (TNBC) has been subdivided into six distinct subgroups: basal-like 1 (BL1), basal-like 2 (BL2), mesenchymal (M), mesenchymal stem–like (MSL), immunomodulatory (IM), and luminal androgen receptor (LAR). We recently identified a subgroup of TNBC with loss of the tumor suppressor PTEN and five specific microRNAs that exhibits exceedingly poor clinical outcome and contains TP53 mutation, RB1 loss and high MYC and WNT signalling. Here, show that these PTEN-low/miRNA-low lesions cluster with BL1 TNBC. These tumors exhibited high RhoA signalling and were significantly stratified on the basis of PTEN-low/RhoA-signalling-high with hazard ratios (HRs) of 8.2 (P = 0.0009) and 4.87 (P = 0.033) in training and test cohorts, respectively. For BL2 TNBC, we identified AKT1 copy gain/high mRNA expression as surrogate for poor prognosis (HR = 3.9; P = 0.02 and HR = 6.1; P = 0.0032). In IM, programmed cell death 1 (PD1) was elevated and predictive of poor prognosis (HR = 5.3; P = 0.01 and HR = 3.5; P < 0.004). Additional alterations, albeit without prognostic power, characterized each subtype including high E2F2 and TGFβ signalling and CXCL8 expression in BL2, high IFNα and IFNγ signalling and CTLA4 expression in IM, and high EGFR signalling in MSL, and may be targeted for therapy. This study identified PTEN-low/RhoA-signalling-high, and high AKT1 and PD1 expression as potent prognostications for BL1, BL2 and IM subtypes with survival differences of over 14, 2.75 and 10.5 years, respectively. This intrinsic heterogeneity could be exploited to prioritize patients for precision medicine.

Download Full-text

PSMB5 is associated with proliferation and drug resistance in triple-negative breast cancer

The International Journal of Biological Markers ◽

10.5301/ijbm.5000283 ◽

2017 ◽

Vol 33 (1) ◽

pp. 102-108 ◽

Cited By ~ 7

Author(s):

Wensong Wei ◽

Yufeng Zou ◽

Qihua Jiang ◽

Zhibin Zhou ◽

Haolong Ding ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative Breast Cancer ◽

Poor Prognosis ◽

Triple Negative ◽

Functional Module ◽

Enrichment Analysis ◽

Chemotherapeutic Agents ◽

Gene Set Enrichment Analysis ◽

Disease Stage ◽

Cancer Subtypes

Background: Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, characterized by advanced disease stage and poor prognosis. Moreover, due to the lack of therapeutic markers, TNBC patients can’t benefit fully from currently available targeted therapies. Methods: To fully understand the molecular basis of TNBC, we used gene set enrichment analysis (GSEA) to screen out the most altered functional module in TNBC, from publicly available microarray data and studied the association of the candidate gene with TNBC development. Results: We found that the proteasome was significantly activated in TNBC. As compared with other breast cancer subtypes and normal tissue, proteasome subunit beta 5 (PSMB5), the key regulator of proteasome function, was overexpressed in TNBC tissue and predictive of poor prognosis. Moreover, we also found that PSMB5 knockdown induced TNBC apoptosis and significantly enhanced cancer cell sensitivity to the chemotherapeutic agents bortezomib and paclitaxel. Conclusions: Our results suggest a potential role for PSMB5 as a biomarker and therapeutic target for TNBC.

Download Full-text

Brachyury, a vaccine target, is overexpressed in triple-negative breast cancer

Endocrine Related Cancer ◽

10.1530/erc-16-0037 ◽

2016 ◽

Vol 23 (10) ◽

pp. 783-796 ◽

Cited By ~ 15

Author(s):

Duane H Hamilton ◽

Mario Roselli ◽

Patrizia Ferroni ◽

Leopoldo Costarelli ◽

Francesco Cavaliere ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative Breast Cancer ◽

Poor Prognosis ◽

Tumor Metastasis ◽

Triple Negative ◽

Strong Association ◽

High Rate ◽

Therapeutic Interventions ◽

Primary Tumors ◽

Cancer Subtypes

Patients diagnosed with triple-negative breast cancer (TNBC) have a high rate of tumor metastasis and a poor prognosis. The treatment option for these patients is currently chemotherapy, which results in very low response rates. Strategies that exploit the immune system for the treatment of cancer have now shown the ability to improve survival in several tumor types. Identifying potential targets for immune therapeutic interventions is an important step in developing novel treatments for TNBC. In this study,in silicoanalysis of publicly available datasets and immunohistochemical analysis of primary and metastatic tumor biopsies from TNBC patients were conducted to evaluate the expression of the transcription factor brachyury, which is a driver of tumor metastasis and resistance and a target for cancer vaccine approaches. Analysis of breast cancer datasets demonstrated a predominant expression of brachyury mRNA in TNBC and in basal vs luminal or HER2 molecular breast cancer subtypes. At the protein level, variable levels of brachyury expression were detected both in primary and metastatic TNBC lesions. A strong association was observed between nuclear brachyury protein expression and the stage of disease, with nuclear brachyury being more predominant in metastatic vs primary tumors. Survival analysis also demonstrated an association between high levels of brachyury in the primary tumor and poor prognosis. Two brachyury-targeting cancer vaccines are currently undergoing clinical evaluation; the data presented here provide rationale for using brachyury-targeting immunotherapy approaches for the treatment of TNBC.

Download Full-text