Distinct tumor protein p53 mutants in breast cancer subgroups

An 8-aminoquinoline-naphthyl copper complex causes apoptotic cell death by modulating the expression of apoptotic regulatory proteins in breast cancer cells

Breast cancer is one of the most common cancers globally and a leading cause of cancer-related deaths among women. Despite the combination of chemotherapy with targeted therapy, including monoclonal antibodies and kinase inhibitors, drug resistance and treatment failure remain a common occurrence. Copper, complexed to various organic ligands, has gained attention as potential chemotherapeutic agents due to its perceived decreased toxicity to normal cells. The cytotoxic efficacy and the mechanism of cell death of an 8-aminoquinoline-naphthyl copper complex (Cu8AqN) in MCF-7 and MDA-MB-231 breast cancer cell lines was investigated. The complex inhibited the growth of MCF-7 and MDA-MB-231 cells with IC50 values of 2.54 ± 0.69 μM and 3.31 ± 0.06 μM, respectively. Nuclear fragmentation, annexin V binding, and increased caspase-3/7 activity indicated apoptotic cell death. The loss of mitochondrial membrane potential, an increase in caspase-9 activity, the absence of active caspase-8 and a decrease of tumour necrosis factor receptor 1(TNFR1) expression supported activation of the intrinsic apoptotic pathway. Increased ROS formation and increased expression of haem oxygenase-1 (HMOX-1) indicated activation of cellular stress pathways. Expression of p21 protein in the nuclei was increased indicating cell cycle arrest, whilst the expression of inhibitor of apoptosis proteins (IAPs); cIAP1, XIAP and survivin were decreased, creating a pro-apoptotic environment. Phosphorylated p53 species; phospho-p53(S15), phospho-p53(S46), and phospho-p53(S392) accumulated in MCF-7 cells indicating the potential of Cu8AqN to restore p53 function in the cells. In combination, the data indicates that Cu8AqN is a useful lead molecule worthy of further exploration as a potential anti-cancer drug.

Alpha-6 integrin deletion delays the formation of Brca1/p53-deficient basal-like breast tumors by restricting luminal progenitor cell expansion

BACKGROUND

The aberrant amplification of mammary luminal progenitors is at the origin of basal-like breast cancers associated with BRCA1 mutations. Integrins mediate cell-matrix adhesion and transmit mechanical and chemical signals that drive epithelial stem cell functions and regulate tumor progression, metastatic reactivation, and resistance to targeted therapies. Consistently, we have recently shown that laminin-binding integrins are essential for the expansion and differentiation of mammary luminal progenitors in physiological conditions. As over-expression of the laminin-binding α6 integrin (Itgα6) is associated with poor prognosis and reduced survival in breast cancer, we here investigate the role of Itgα6 in mammary tumorigenesis.

METHODS

We used Blg-Cre; Brca1F/F; Trp53F/F mice, a model that phenocopies human basal-like breast cancer with BRCA1 mutations. We generated mutant mice proficient or deficient in Itgα6 expression and followed tumor formation. Mammary tumors and pretumoral tissues were characterized by immunohistochemistry, flow cytometry, RT-qPCR, Western blotting and organoid cultures. Clonogenicity of luminal progenitors from preneoplastic glands was studied in 3D Matrigel cultures.

RESULTS

We show that Itga6 deletion favors activation of p16 cell cycle inhibitor in the preneoplastic tissue. Subsequently, the amplification of luminal progenitors, the cell of origin of Brca1-deficient tumors, is restrained in Itgα6-deficient gland. In addition, the partial EMT program operating in Brca1/p53-deficient epithelium is attenuated in the absence of Itgα6. As a consequence of these events, mammary tumor formation is delayed in Itgα6-deficient mice. After tumor formation, the lack of Itgα6 does not affect tumor growth but rather alters their differentiation, resulting in reduced expression of basal cell markers.

CONCLUSIONS

Our data indicate that Itgα6 has a pro-tumorigenic role in Blg-Cre; Brca1F/F; Trp53F/F mice developing basal-like mammary tumors. In particular, we reveal that Itgα6 is required for the luminal progenitor expansion and the aberrant partial EMT program that precedes the formation of BRCA1 deficient tumors.

p53 Dysregulation in Breast Cancer: Insights on Mutations in the TP53 Network and p53 Isoform Expression

In breast cancer, p53 expression levels are better predictors of outcome and chemotherapy response than TP53 mutation. Several molecular mechanisms that modulate p53 levels and functions, including p53 isoform expression, have been described, and may contribute to deregulated p53 activities and worse cancer outcomes. In this study, TP53 and regulators of the p53 pathway were sequenced by targeted next-generation sequencing in a cohort of 137 invasive ductal carcinomas and associations between the identified sequence variants, and p53 and p53 isoform expression were explored. The results demonstrate significant variability in levels of p53 isoform expression and TP53 variant types among tumours. We have shown that TP53 truncating and missense mutations modulate p53 levels. Further, intronic mutations, particularly polymorphisms in intron 4, which can affect the translation from the internal TP53 promoter, were associated with increased Δ133p53 levels. Differential expression of p53 and p53 isoforms was associated with the enrichment of sequence variants in p53 interactors BRCA1, PALB2, and CHEK2. Taken together, these results underpin the complexity of p53 and p53 isoform regulation. Furthermore, given the growing evidence associating dysregulated levels of p53 isoforms with cancer progression, certain TP53 sequence variants that show strong links to p53 isoform expression may advance the field of prognostic biomarker study in breast cancer.

p53 Expression in Luminal Breast Cancer Correlates With TP53 Mutation and Primary Endocrine Resistance

TP53 mutation is associated with primary endocrine resistance in luminal breast cancer (BC). Nuclear accumulation of p53, as determined by immunohistochemistry (IHC), is a surrogate marker for TP53 mutation. The immunohistochemical p53 index that defines a p53-positive status is not well established. This study determined the optimal p53 index cutoff to identify luminal BCs harboring TP53 mutations. In total, 364 luminal BCs from the West German Study Group ADAPT trial (NCT01779206) were analyzed for TP53 mutations by next-generation sequencing and for p53 expression by IHC (DO-7 antibody). P53 indices were determined by automated image analysis. All tumors were from patients treated with short-term preoperative endocrine therapy (pET; tamoxifen or aromatase inhibitor) before tumor resection. IHC evaluation included needle biopsies before therapy (baseline) and resections specimens after therapy (post-pET). Optimal p53 index cutoffs were defined with Youden statistics. TP53 mutations were detected in 16.3% of BC cases. The median p53 indices were significantly higher in TP53-mutated BCs compared to BCs harboring wild-type TP53 (baseline: 47.0% vs 6.4%, P < .001; post-pET: 50.1% vs 1.1%, P < .001). Short-term pET decreased p53 indices in BCs harboring wild-type TP53 (P < .001) but not in TP53-mutated BCs (P = .102). For baseline biopsies, the optimal p53 index cutoff was ≥34.6% (specificity 0.92, sensitivity 0.63, Youden index 0.54, accuracy: 0.87). For post-pET specimens, the optimal cutoff was ≥25.3% (specificity 0.95, sensitivity 0.65, Youden index 0.60, accuracy: 0.90). Using these cutoffs to define the p53 status, p53-positive BCs were >2-fold more common in pET nonresponders compared to pET responders (baseline: 37/162, 22.8% vs 18/162, 11.1%, P = .007; post-pET: 36/179, 20.1% vs 16/179, 8.9%, P = .004). In summary, IHC for p53 identifies TP53-mutated luminal BCs with high specificity and accuracy. Optimal cutoffs are ≥35% and ≥25% for treatment-naïve and endocrine-pretreated patients, respectively.

Mutant p53 in cancer: from molecular mechanism to therapeutic modulation

TP53, a crucial tumor suppressor gene, is the most commonly mutated gene in human cancers. Aside from losing its tumor suppressor function, mutant p53 (mutp53) often acquires inherent, novel oncogenic functions, which is termed "gain-of-function". Emerging evidence suggests that mutp53 is highly associated with advanced malignancies and poor prognosis, which makes it a target for development of novel cancer therapies. Herein, we provide a summary of our knowledge of the mutp53 types and mutp53 spectrum in cancers. The mechanisms of mutp53 accumulation and gain-of-function are also summarized. Furthermore, we discuss the gain-of-function of mutp53 in cancers: genetic instability, ferroptosis, microenvironment, and stemness. Importantly, the role of mutp53 in the clinic is also discussed, particularly with regard to chemotherapy and radiotherapy. Last, emphasis is given to emerging strategies on how to target mutp53 for tumor therapy. Thus, this review will contribute to better understanding of the significance of mutp53 as a target for therapeutic strategies.

Aberrant phosphorylation inactivates Numb in breast cancer causing expansion of the stem cell pool

Asymmetric cell division is a key tumor suppressor mechanism that prevents the uncontrolled expansion of the stem cell (SC) compartment by generating daughter cells with alternative fates: one retains SC identity and enters quiescence and the other becomes a rapidly proliferating and differentiating progenitor. A critical player in this process is Numb, which partitions asymmetrically at SC mitosis and inflicts different proliferative and differentiative fates in the two daughters. Here, we show that asymmetric Numb partitioning per se is insufficient for the proper control of mammary SC dynamics, with differential phosphorylation and functional inactivation of Numb in the two progeny also required. The asymmetric phosphorylation/inactivation of Numb in the progenitor is mediated by the atypical PKCζ isoform. This mechanism is subverted in breast cancer via aberrant activation of PKCs that phosphorylate Numb in both progenies, leading to symmetric division and expansion of the cancer SC compartment, associated with aggressive disease. Thus, Numb phosphorylation represents a target for breast cancer therapy.

Differences in somatic TP53 mutation type in breast tumors by race and receptor status

PURPOSE

Somatic driver mutations in TP53 are associated with triple-negative breast cancer (TNBC) and poorer outcomes. Breast cancers in women of African ancestry (AA) are more likely to be TNBC and have somatic TP53 mutations than cancers in non-Hispanic White (NHW) women. Missense driver mutations in TP53 have varied functional impact including loss-of-function (LOF) or gain-of-function (GOF) activity, and dominant negative (DNE) effects. We aimed to determine if there were differences in somatic TP53 mutation types by patient ancestry or TNBC status.

METHODS

We identified breast cancer datasets with somatic TP53 mutation data, ancestry, age, and hormone receptor status. Mutations were classified for functional impact using published data and type of mutation. We assessed differences using Fisher's exact test.

RESULTS

From 96 breast cancer studies, we identified 2964 women with somatic TP53 mutations: 715 (24.1%) Asian, 258 (8.7%) AA, 1931 (65.2%) NHW, and 60 (2%) Latina. The distribution of TP53 mutation type was similar by ancestry. However, 35.8% of tumors from NHW individuals had GOF mutations compared to 29% from AA individuals (p = 0.04). Mutations with DNE activity were positively associated with TNBC (OR 1.37, p = 0.03) and estrogen receptor (ER) negative status (OR 1.38; p = 0.005).

CONCLUSIONS

Somatic TP53 mutation types did not differ by ancestry overall, but GOF mutations were more common in NHW women than AA women. ER-negative and TNBC tumors are less likely to have DNE+ TP53 mutations which could reflect biological processes. Larger cohorts and functional studies are needed to further elucidate these findings.

Association between TP53 mutation and high 21-gene recurrence score in estrogen receptor-positive/HER2-negative breast cancer

We investigated the association between TP53 mutation and 21-gene recurrence score (RS) in ER-positive/HER2-negative breast cancer (BC) using data from 141 patients who underwent TP53 sequencing and Oncotype DX^® tests. We detected TP53 mutations in 18 (12.8%) patients. Most patients with TP53 mutation had a high 21-gene RS (≥26). The average 21-gene RS was higher in TP53 mutant tumors. Multivariate analysis showed that mutated TP53 is an independent factor for a high 21-gene RS. Mutated TP53 remained closely associated with high 21-gene RS in patients with low pathological risk (n = 103). In the ER⁺/PR⁺/HER2-negative subset (n = 356) of The Cancer Genome Atlas, the non-luminal A intrinsic subtype was more prevalent in the group with mutant TP53. mRNA levels of p53-regulated senescence gatekeeper and cell cycle-related genes were increased in BC with mutated TP53. Mutational analysis of TP53 helped identify endocrine-resistant tumors.

Breast Cancer-Epidemiology, Risk Factors, Classification, Prognostic Markers, and Current Treatment Strategies-An Updated Review

Simple Summary

Breast cancer is the most common cancer among women. It is estimated that 2.3 million new cases of BC are diagnosed globally each year. Based on mRNA gene expression levels, BC can be divided into molecular subtypes that provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. This review addresses the overview on the BC epidemiology, risk factors, classification with an emphasis on molecular types, prognostic biomarkers, as well as possible treatment modalities.

Abstract

Breast cancer (BC) is the most frequently diagnosed cancer in women worldwide with more than 2 million new cases in 2020. Its incidence and death rates have increased over the last three decades due to the change in risk factor profiles, better cancer registration, and cancer detection. The number of risk factors of BC is significant and includes both the modifiable factors and non-modifiable factors. Currently, about 80% of patients with BC are individuals aged >50. Survival depends on both stage and molecular subtype. Invasive BCs comprise wide spectrum tumors that show a variation concerning their clinical presentation, behavior, and morphology. Based on mRNA gene expression levels, BC can be divided into molecular subtypes (Luminal A, Luminal B, HER2-enriched, and basal-like). The molecular subtypes provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. The eighth edition of TNM classification outlines a new staging system for BC that, in addition to anatomical features, acknowledges biological factors. Treatment of breast cancer is complex and involves a combination of different modalities including surgery, radiotherapy, chemotherapy, hormonal therapy, or biological therapies delivered in diverse sequences.

The noncoding RNAs SNORD50A and SNORD50B-mediated TRIM21-GMPS interaction promotes the growth of p53 wild-type breast cancers by degrading p53

Small nucleolar RNA SNORD50A and SNORD50B (SNORD50A/B) has been reported to be recurrently deleted and function as a putative tumor suppressor in different types of cancer by binding to and suppressing the activity of the KRAS oncoproteins. Its deletion correlates with poorer patient survival. However, in this study, we surprisingly found that SNORD50A/B loss predicted a better survival in breast cancer patients carrying wild-type p53. Functional studies showed that SNORD50A/B deletion strongly inhibited the proliferation, migration, invasion and tumorigenic potential, and induced cell cycle arrest and apoptosis in p53 wild-type breast cancer cells, while exerted the opposite effects in p53 mutated breast cancer cells. This was also supported by ectopically expressing SNORD50A/B in both p53 wild-type and mutated breast cancer cells. Mechanistically, SNORD50A/B clearly enhances the interaction between E3 ubiquitin ligase TRIM21 and its substrate GMPS by forming a complex among them, thereby promoting GMPS ubiquitination and its subsequent cytoplasmic sequestration. SNORD50A/B deletion in p53 wild-type breast cancer cells will release GMPS and induce the translocation of GMPS into the nucleus, where GMPS can recruit USP7 and form a complex with p53, thereby decreasing p53 ubiquitination, stabilizing p53 proteins, and inhibiting malignant phenotypes of cancer cells. Altogether, the present study first reports that SNORD50A/B plays an oncogenic role in p53 wild-type breast cancers by mediating TRIM21-GMPS interaction.

The repair gene BACH1 - a potential oncogene

BACH1 encodes for a protein that belongs to RecQ DEAH helicase family and interacts with the BRCT repeats of BRCA1. The N-terminus of BACH1 functions in DNA metabolism as DNA-dependent ATPase and helicase. The C-terminus consists of BRCT domain, which interacts with BRCA1 and this interaction is one of the major regulator of BACH1 function. BACH1 plays important roles both in phosphorylated as well as dephosphorylated state and functions in coordination with multiple signaling molecules. The active helicase property of BACH1 is maintained by its dephosphorylated state. Imbalance between these two states enhances the development and progression of the diseased condition. Currently BACH1 is known as a tumor suppressor gene based on the presence of its clinically relevant mutations in different cancers. Through this review we have justified it to be named as an oncogene. In this review, we have explained the mechanism of how BACH1 in collaboration with BRCA1 or independently regulates various pathways like cell cycle progression, DNA replication during both normal and stressed situation, recombination and repair of damaged DNA, chromatin remodeling and epigenetic modifications. Mutation and overexpression of BACH1 are significantly found in different cancer types. This review enlists the molecular players which interact with BACH1 to regulate DNA metabolic functions, thereby revealing its potential for cancer therapeutics. We have identified the most mutated functional domain of BACH1, the hot spot for tumorigenesis, justifying it as a target molecule in different cancer types for therapeutics. BACH1 has high potentials of transforming a normal cell into a tumor cell if compromised under certain circumstances. Thus, through this review, we justify BACH1 as an oncogene along with the existing role of being a tumor suppressant.

From Conventional to Precision Therapy in Canine Mammary Cancer: A Comprehensive Review

Canine mammary tumors (CMTs) are the most common neoplasm in intact female dogs. Canine mammary cancer (CMC) represents 50% of CMTs, and besides surgery, which is the elective treatment, additional targeted and non-targeted therapies could offer benefits in terms of survival to these patients. Also, CMC is considered a good spontaneous intermediate animal model for the research of human breast cancer (HBC), and therefore, the study of new treatments for CMC is a promising field in comparative oncology. Dogs with CMC have a comparable disease, an intact immune system, and a much shorter life span, which allows the achievement of results in a relatively short time. Besides conventional chemotherapy, innovative therapies have a large niche of opportunities. In this article, a comprehensive review of the current research in adjuvant therapies for CMC is conducted to gather available information and evaluate the perspectives. Firstly, updates are provided on the clinical-pathological approach and the use of conventional therapies, to delve later into precision therapies against therapeutic targets such as hormone receptors, tyrosine kinase receptors, p53 tumor suppressor gene, cyclooxygenases, the signaling pathways involved in epithelial-mesenchymal transition, and immunotherapy in different approaches. A comparison of the different investigations on targeted therapies in HBC is also carried out. In the last years, the increasing number of basic research studies of new promising therapeutic agents on CMC cell lines and CMC mouse xenografts is outstanding. As the main conclusion of this review, the lack of effort to bring the in vitro studies into the field of applied clinical research emerges. There is a great need for well-planned large prospective randomized clinical trials in dogs with CMC to obtain valid results for both species, humans and dogs, on the use of new therapies. Following the One Health concept, human and veterinary oncology will have to join forces to take advantage of both the economic and technological resources that are invested in HBC research, together with the innumerable advantages of dogs with CMC as a spontaneous animal model.

Fibroblast growth factor receptor 4 as a prognostic indicator in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) constitutes up to 15% of all breast cancers. It is one of the most aggressive breast cancers and is more prone to metastasize compared with other subtypes. Breast cancer patients with this subtype usually have a poor prognosis. Fibroblast growth factor receptor 4 (FGFR4) belongs to the receptor tyrosine kinase (RTK) family, and early analyses identified that FGFR4 was involved in breast cancer. However, the prognostic effect of FGFR4 on TNBC is unknown. In the present study, we investigated the association between FGFR4 and TNBC prognosis.

Methods

A total of 282 TNBC patients were enrolled. FGFR4 protein expression was detected in these 282 TNBC patients using immunohistochemistry (IHC).

Results

In the present study, FGFR4 was highly expressed in TNBC patients. Lymph node metastasis (LNM) (P=0.033) and p53 status (P=0.019) were associated with high FGFR4 expression. Univariate analysis identified high FGFR4 expression (P=0.016) as a prognostic predictor, and multivariate analysis found that high FGFR4 expression (P=0.016) was an independent prognostic factor. The Kaplan-Meier survival curve showed that high FGFR4 protein expression was correlated with poorer overall survival (OS).

Conclusions

The results of our present study show that FGFR4 protein expression is correlated with a worse prognosis in TNBC.

Metabolism and immunity in breast cancer

Breast cancer is one of the most common malignancies that seriously threaten women's health. In the process of the malignant transformation of breast cancer, metabolic reprogramming and immune evasion represent the two main fascinating characteristics of cancer and facilitate cancer cell proliferation. Breast cancer cells generate energy through increased glucose metabolism. Lipid metabolism contributes to biological signal pathways and forms cell membranes except energy generation. Amino acids act as basic protein units and metabolic regulators in supporting cell growth. For tumor-associated immunity, poor immunogenicity and heightened immunosuppression cause breast cancer cells to evade the host's immune system. For the past few years, the complex mechanisms of metabolic reprogramming and immune evasion are deeply investigated, and the genes involved in these processes are used as clinical therapeutic targets for breast cancer. Here, we review the recent findings related to abnormal metabolism and immune characteristics, regulatory mechanisms, their links, and relevant therapeutic strategies.

Assessment of stromal tumor infiltrating lymphocytes and immunohistochemical features in invasive micropapillary breast carcinoma with long-term outcomes

PURPOSE

We studied the long-term outcomes of invasive micropapillary carcinoma (IMPCs) of the breast in relation to stromal tumor infiltrating lymphocytes (sTILs), prognostic biomarkers and clinicopathological features.

METHODS

Stage I-III IMPCs treated with upfront surgery at our institution (January 2000 and December 2016) were included. Central pathology review was performed and sTILs (including zonal distribution and hot spot analysis) and tumor-associated plasma cells (TAPC) were evaluated. Expression of P53, BCL2, FOXP3, and WT1, which are variably linked to breast cancer prognosis, was measured by immunohistochemistry using tissue microarrays. Time-to-event endpoints were distant recurrence free interval (DRFI) and breast cancer-specific survival (BCSS).

RESULTS

We included 111 patients of whom 59% were pure IMPCs. Standard clinicopathological features were comparable between pure and non-pure IMPCs. Overall, the mean sTILs level was 20% with higher proportion of sTILs present at the invasive front. There were no significant differences between pure- and non-pure IMPCs in sTILs levels, nor in the spatial distribution of the hot spot regions or in the distribution of TAPC. Higher sTILs correlated with worse DRFI (HR = 1.55; p = 0.0172) and BCSS (HR = 2.10; p < 0.001).

CONCLUSIONS

Clinicopathological features, geographical distribution of sTILs and TAPC are similar between pure and non-pure IMPCs. Despite a high proportion of grade 3 tumors and lymph node involvement, we observed a low rate of distant recurrences and breast cancer-related death in this cohort of stage I-III IMPCs treated with primary surgery. Caution in interpretation of the observed prognostic correlations is required given the very low number of events, warranting validation in other cohorts.

Spectrum of TP53 Mutations in BRCA1/2 Associated High-Grade Serous Ovarian Cancer

Objective: Mutations in TP53 lead to loss of function (LOF) or gain of function (GOF) of the corresponding protein p53 and produce a different effect on the tumor. Our goal was to determine the spectrum of somatic TP53 variants in BRCA1/2 associated high-grade serous ovarian cancer (HGSOC).

Methods: The population under study comprised of HGSOCs with pathogenic variants in BRCA1 (n = 78) or BRCA2 (n = 21). Only chemo-naive and platinum-sensitive patients were included in this study. The case group of the IARC database (n = 1249) with HGSOC not stratified by BRCA status was used as a reference. A custom NGS panel was used for sequencing TP53 and mutational hot-spots of other genes, and p53 expression was evaluated by immunohistochemistry for 68 cases of HGSOCs.

Results: Somatic TP53 variants (95) or inhibition of wild-type p53 expression (3) were observed in 98 cases. The sample with normal p53 had CDKNA1 variants. The frequency of truncating variants was significantly higher than in the reference cohort (30.3 vs. 21.0%, p = 0.01). Most of the samples (41/68) demonstrated low (or absent) expression of p53, and 17 samples overexpressed p53. LOH was typical for TP53 nonsense variants (14/15). In total, 68/95 samples were LOH positive and showed LOH in all tumorous cells, thus indicating the driver effect of TP53 mutations. Three specimens had KRAS, BAX, APC, and CTNNB1 subclones variants.

Conclusion: High frequency of TP53 truncating variants, the low expression of mutant p53, and low incidence of oncogene mutations show potential GOF properties of p53 to be poorly represented in BRCA1/2 associated HGSOC.

Characterization of circulating breast cancer cells with tumorigenic and metastatic capacity

Functional studies giving insight into the biology of circulating tumor cells (CTCs) remain scarce due to the low frequency of CTCs and lack of appropriate models. Here, we describe the characterization of a novel CTC‐derived breast cancer cell line, designated CTC‐ITB‐01, established from a patient with metastatic estrogen receptor‐positive (ER⁺) breast cancer, resistant to endocrine therapy. CTC‐ITB‐01 remained ER⁺ in culture, and copy number alteration (CNA) profiling showed high concordance between CTC‐ITB‐01 and CTCs originally present in the patient with cancer at the time point of blood draw. RNA‐sequencing data indicate that CTC‐ITB‐01 has a predominantly epithelial expression signature. Primary tumor and metastasis formation in an intraductal PDX mouse model mirrored the clinical progression of ER⁺ breast cancer. Downstream ER signaling was constitutively active in CTC‐ITB‐01 independent of ligand availability, and the CDK4/6 inhibitor Palbociclib strongly inhibited CTC‐ITB‐01 growth. Thus, we established a functional model that opens a new avenue to study CTC biology.

Anticancer bioactive peptide combined with docetaxel and its mechanism in the treatment of breast cancer

Breast cancer remains a worldwide public-health issue. Novel drugs that increase the sensitivity and reduce the toxic side effects of chemotherapeutic agents are urgently required. The present study investigated the effect and mechanism of the short-term intermittent administration of an anticancer bioactive peptide (ACBP), docetaxel (DTX), ACBP combined with DTX (MIX) and ACBP combined with low dose DTX (L-MIX) to nude mice bearing human breast cancer tumors. The body weight, tumor length, tumor diameter, diet and water consumption of the tumor-bearing nude mice were calculated. The protein and mRNA expression levels of p53, p21 and Ki67 were detected via immunohistochemistry and reverse transcription-quantitative PCR, respectively. The results revealed that the activity level of each group of mice was consistent. However, the food and water consumption of the ACBP group was significantly increased compared with the NS group. Compared with the normal saline group, the tumor weights and volumes of the treatment groups were significantly decreased, indicating an inhibitory effect of the treatment. However, the MIX group exhibited lower tumor weights and volumes compared with the ACBP and DTX groups. Furthermore, no significant cell necrosis, edema or inflammatory cell infiltration was observed upon hematoxylin & eosin staining of the liver and spleen in all groups. The results also revealed that the p21, p53 and Ki67 protein and mRNA levels were decreased in the ACBP, DTX and MIX groups compared with the control group. Additionally, when compared with those in the MIX and L-MIX groups, the p21 and Ki67 protein, and p53 and Ki67 mRNA levels in the ACBP and DTX groups were significantly increased. The results suggested that the short-term intermittent use of ACBP alone had an inhibitory effect on tumor growth and improved the food and water consumption of tumor-bearing nude mice. Furthermore, the combination of ACBP and DTX reduced toxic side effects and the dosage requirement of drugs to achieve therapeutic effects on the tumor-bearing nude mice. Therefore, the antitumor effect of ACBP may be associated with the improvement of immune function in tumor-bearing nude mice and ACBP may serve an antitumor role via the p53-p21 signaling pathway in breast cancer.

Clinical spectrum and prognostic value of TP53 mutations in circulating tumor DNA from breast cancer patients in China

Background

TP53 mutations are common in breast cancer. There is currently no large‐scale cohort study to investigate the TP53 landscape in breast cancer patients from China. The predictive value of TP53 mutations for the efficacy of human epidermal growth factor receptor 2 (HER2)‐targeted therapy in breast cancer remains controversial. In the present study, we aimed to analyze the clinical spectrum and prognostic value of TP53 mutations in circulating tumor DNA (ctDNA) from breast cancer patients in China.

Methods

We retrospectively analyzed the clinical data and TP53 mutation features in ctDNA samples from 804 patients with metastatic breast cancer. TP53 mutations were detected by target region capture‐based next‐generation sequencing. The relationship between TP53 mutation status and disease‐free survival (DFS) was analyzed in 444 patients with metastatic breast cancer. Moreover, the relationship between TP53 mutation status and progression‐free survival (PFS) was analyzed in 55 HER2‐positive patients treated with first‐line trastuzumab‐based therapy. Kaplan‐Meier analysis was performed to estimate the survival curves of the different subgroups, and the log‐rank test was used to compare the curves. A Cox regression model was used to estimate multivariable‐adjusted hazard ratios and their 95% confidence intervals (CIs) associated with the DFS and PFS.

Results

Among the 804 investigated patients, 431 (53.6%) patients harbored TP53 mutations. TP53 mutations were differentially distributed among different molecular subtypes of breast cancer (P < 0.05). Patients with TP53 mutations had a shorter DFS than those with wild‐type TP53 (hazard ratio = 1.32, 95% CI = 1.09‐1.61, P = 0.005). TP53 mutations in exons 5‐8 were associated with worse outcome (hazard ratio = 1.50, 95% CI = 1.11‐2.03, P = 0.009). However, TP53 mutation status was not significantly associated with PFS in HER2‐positive patients who received first‐line trastuzumab‐based therapy (P = 0.966). Interestingly, in the taxane combination group, patients with TP53 mutations exhibited longer PFS than those without TP53 mutations (hazard ratio = 0.08, 95% CI = 0.02‐0.30, P < 0.001). However, in the non‐taxane combination group, patients with TP53 mutations displayed shorter PFS than those with wild‐type TP53 (hazard ratio = 4.84, 95% CI = 1.60‐14.66, P = 0.005).

Conclusions

TP53 mutations in exons 5‐8 may be an independent prognostic marker for short DFS in patients with metastatic breast cancer. TP53 mutations had opposite effects on trastuzumab‐treated patients treated with and without taxanes.

Prediction of Oncotype DX recurrence score using deep multi-layer perceptrons in estrogen receptor-positive, HER2-negative breast cancer

Oncotype DX (ODX) is a multi-gene expression signature designed for estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients to predict the recurrence score (RS) and chemotherapy (CT) benefit. The aim of our study is to develop a prediction tool for the three RS's categories based on deep multi-layer perceptrons (DMLP) and using only the morphoimmunohistological variables. We performed a retrospective cohort of 320 patients who underwent ODX testing from three French hospitals. Clinico-pathological characteristics were recorded. We built a supervised machine learning classification model using Matlab software with 152 cases for the training and 168 cases for the testing. Three classifiers were used to learn the three risk categories of the ODX, namely the low, intermediate, and high risk. Experimental results provide the area under the curve (AUC), respectively, for the three risk categories: 0.63 [95% confidence interval: (0.5446, 0.7154), p < 0.001], 0.59 [95% confidence interval: (0.5031, 0.6769), p < 0.001], 0.75 [95% confidence interval: (0.6184, 0.8816), p < 0.001]. Concordance rate between actual RS and predicted RS ranged from 53 to 56% for each class between DMLP and ODX. The concordance rate of low and intermediate combined risk group was 85%.We developed a predictive machine learning model that could help to define patient's RS. Moreover, we integrated histopathological data and DMLP results to select tumor for ODX testing. Thus, this process allows more relevant use of histopathological data, and optimizes and enhances this information.

Gain of function in somatic TP53 mutations is associated with immune-rich breast tumors and changes in tumor-associated macrophages

BACKGROUND

Somatic mutations in TP53 are present in 20%-30% of all breast tumors. While there are numerous population-based analyses of TP53, yet none have examined the relationship between somatic mutations in TP53 and tumor invasive immune cells.

METHODS

Clinical and genetic data from 601 women drawn from The Cancer Genome Atlas (TCGA) were used to test the association between somatic TP53 mutation and immune-rich or immune-poor tumor status; determined using the CIBERSORT-based gene expression signature of 22 immune cell types. Our validation dataset, the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), used a pathologist-determined measure of lymphocyte infiltration.

RESULTS

Within TP53-mutated samples, a mutation at codon p.R175H was shown to be present at higher frequency in immune-rich tumors. In validation analysis, any somatic mutation in TP53 was associated with immune-rich status, and the mutation at p.R175H had a significant association with tumor-invasive lymphocytes. TCGA-only analysis of invasive immune cell type identified an increase in M0 macrophages associated with p.R175H.

CONCLUSIONS

These findings suggest that TP53 somatic mutations, particularly at codon p.R175H, are enriched in tumors with infiltrating immune cells. Our results confirm recent research showing inflammation-related gain of function in specific TP53 mutations.

Clinicopathological and epidemiological significance of breast cancer subtype reclassification based on p53 immunohistochemical expression

TP53 mutations are common in breast cancer and are typically associated with more aggressive tumor characteristics, but little is known about the clinicopathological and epidemiological relevance of p53 protein expression, a TP53 mutation surrogate, in breast cancer subtypes. In this study of 7226 Chinese women with invasive breast cancer, we defined breast cancer subtypes using immunohistochemical (IHC) measures of hormone receptors and HER2 in conjunction with histologic grade. p53 expression status was then used to further stratify subtypes into p53-positive and p53-negative. Odds ratios (ORs) and 95% confidence intervals (CIs) in case-only logistic regression analyses were used to examine heterogeneity across different subtypes. The frequency of p53 protein expression varied by breast cancer subtype, being lowest in the luminal A-like and highest in the triple-negative and HER2-enriched subtypes (P-value < 0.01). In luminal A-like and B-like/HER2-negative subtypes, p53 positivity was associated with early-onset tumors, high grade, high proliferative index, and basal marker (CK5/6 and EGFR) expression. Further, compared with luminal A-like/p53-negative patients, A-like/p53-positive patients were more likely to be parous [adjusted OR parous vs. nulliparous = 2.67 (1.60, 4.51); P-value < 0.01] and to have breastfed [adjusted OR ever vs. never = 1.38 (1.03, 1.85); P-value = 0.03]. p53 positivity was not associated with examined clinical and risk factors in other tumor subtypes. Overall, these findings suggest that p53 expression, which is readily available in many settings, can be used to identify phenotypes of luminal A-like breast cancer with distinct clinical and epidemiological implications.

A Review of the Hereditary Component of Triple Negative Breast Cancer: High- and Moderate-Penetrance Breast Cancer Genes, Low-Penetrance Loci, and the Role of Nontraditional Genetic Elements

Triple negative breast cancer (TNBC), representing 10-15% of breast tumors diagnosed each year, is a clinically defined subtype of breast cancer associated with poor prognosis. The higher incidence of TNBC in certain populations such as young women and/or women of African ancestry and a unique pathological phenotype shared between TNBC and BRCA1-deficient tumors suggest that TNBC may be inherited through germline mutations. In this article, we describe genes and genetic elements, beyond BRCA1 and BRCA2, which have been associated with increased risk of TNBC. Multigene panel testing has identified high- and moderate-penetrance cancer predisposition genes associated with increased risk for TNBC. Development of large-scale genome-wide SNP assays coupled with genome-wide association studies (GWAS) has led to the discovery of low-penetrance TNBC-associated loci. Next-generation sequencing has identified variants in noncoding RNAs, viral integration sites, and genes in underexplored regions of the human genome that may contribute to the genetic underpinnings of TNBC. Advances in our understanding of the genetics of TNBC are driving improvements in risk assessment and patient management.

Ki-67, p53 and BCL-2 Expressions and their Association with Clinical Histopathology of Breast Cancer among Women in Tanzania

This study associated Ki-67, p53, and BCL-2 markers with clinical histopathological (CH) features using currently available limited data on these markers in Tanzania. Retrospective chart review study was conducted among females with confirmed breast cancer (BC) at Muhimbili National Hospital in Tanzania between 2016 and 2017. Inclusion criteria were met by 76 patients with a mean age of 51.32 ± 14.28 years. Of these, 86.4% were stage III and IV, whereas 83.5% cases had grade 2 and grade 3. Upon immunostaining, 85.5% and 57.9% were Ki-67 and BCL-2 positive respectively. Log-linear analysis showed no statistically significant association among biomarkers expression and CH features. However, multinomial linear regression showed higher possibility for association between high expression of Ki-67, low expression of p53 and high expression of BCL-2 with age, grade, stage and tumor (T) stage. BCL-2 was positively correlated with Ki-67 expression contrary to p53, which was negatively correlated with BCL-2. Conclusively, there is evidence of correlation between the studied markers with CH features. However, studies with larger sample sizes will likely reveal significant associations that will validate the role of these markers as tools for evaluating treatment response in individualized therapeutic schemes in Tanzania.

Epigenetic reprogramming of epithelial mesenchymal transition in triple negative breast cancer cells with DNA methyltransferase and histone deacetylase inhibitors

Background

Triple negative breast cancer (TNBC) is an aggressive neoplasia with no effective therapy. Our laboratory has developed a unique TNBC cell model presenting epithelial mesenchymal transition (EMT) a process known to be important for tumor progression and metastasis. There is increasing evidence showing that epigenetic mechanisms are involved in the activation of EMT. The objective of this study is to epigenetically reverse the process of EMT in TNBC by using DNA methyltransferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi).

Methods

We evaluated the antitumor effect of three DNMTi and six HDACi using our TNBC cell model by MTT assay, migration and invasion assay, three dimensional culture, and colony formation assay. We then performed the combined treatment both in vitro and in vivo using the most potent DNMTi and HDACi, and tested the combined treatment in a panel of breast cancer cell lines. We investigated changes of EMT markers and potential signaling pathways associated with the antitumor effects.

Results

We showed that DNMTi and HDACi can reprogram highly aggressive TNBC cells that have undergone EMT to a less aggressive phenotype. SGI-110 and MS275 are superior to other seven compounds being tested. The combination of SGI with MS275 exerts a greater effect than single agent alone in inhibiting cell proliferation, motility, colony formation, and stemness of cancer cells. We also demonstrated that MS275 and the combination of SGI with MS275 exert in vivo antitumor effect. We revealed that the combined treatment synergistically reverses EMT through inhibiting EpCAM cleavage and WNT signaling, suppressing mutant p53, ZEB1, and EZH2, and inducing E-cadherin, apoptosis, as well as histone H3 tri-methylation.

Conclusions

Our study showed that DNMTi and HDACi exert antitumor activity in TNBC cells partially by epigenetically reprograming EMT. Our findings strongly suggest that TNBC is sensitive to epigenetic therapies. Therefore, we propose a new strategy to treat TNBC by using the combination of SGI-110 with MS275, which exerts superior antitumor effects by simultaneously targeting multiple pathways.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0988-8) contains supplementary material, which is available to authorized users.

Prevalence of MDM2 amplification and coalterations in 523 advanced cancer patients in the MD Anderson phase 1 clinic

Background

TP53 is the most commonly mutated gene in cancer and codes for the best studied tumor suppressor, p53. MDM2 is involved in the negative regulation of p53 and itself serves as an oncogene, reported to be overexpressed in several cancer tumor types. In this retrospective study, we assessed the occurrence of MDM2 amplification among patients with various types of cancers and its association with clinical factors, other genetic aberrations, and response to targeted therapy in a phase I clinical trial setting.

Methods

Samples from patients with advanced solid tumors who had been referred to the MD Anderson phase I clinical trials program between January 2011 and January 2016 were collected and analyzed for MDM2 amplification using FoundationOne's genomic profiling assay. Patients whose tumors expressed MDM2 amplification were compared to those with tumors of the same histologic types without MDM2 amplification.

Results

We tested tumors from 523 patients, of which 23 (4.4%) had MDM2 amplification. The highest prevalence of MDM2 amplification was in sarcoma (57%), breast cancer (13%) and bladder cancer (9%). Six patients with liposarcoma were treated on phase I protocol with an MDM2 inhibitor. The most common molecular aberrations co-occurring with MDM2 amplification was CDK4 amplification (70%). TP53 mutation was also detected in 7 patients (30%).

Conclusion

MDM2 amplification was most commonly associated with liposarcoma. Concomitant alterations in additional genes such as CDK4 amplification and TP53 mutations, along with variable responses to targeted therapies including MDM2 inhibitors, suggest that further combinational studies are needed to target this population.

Cyclin E Overexpression Sensitizes Triple-Negative Breast Cancer to Wee1 Kinase Inhibition

PURPOSE

Poor prognosis in triple-negative breast cancer (TNBC) is due to an aggressive phenotype and lack of biomarker-driven targeted therapies. Overexpression of cyclin E and phosphorylated-CDK2 are correlated with poor survival in patients with TNBC, and the absence of CDK2 desensitizes cells to inhibition of Wee1 kinase, a key cell-cycle regulator. We hypothesize that cyclin E expression can predict response to therapies, which include the Wee1 kinase inhibitor, AZD1775.

EXPERIMENTAL DESIGN

Mono- and combination therapies with AZD1775 were evaluated in TNBC cell lines and multiple patient-derived xenograft (PDX) models with different cyclin E expression profiles. The mechanism(s) of cyclin E-mediated replicative stress were investigated following cyclin E induction or CRISPR/Cas9 knockout by a number of assays in multiple cell lines.

RESULTS

Cyclin E overexpression (i) is enriched in TNBCs with high recurrence rates, (ii) sensitizes TNBC cell lines and PDX models to AZD1775, (iii) leads to CDK2-dependent activation of DNA replication stress pathways, and (iv) increases Wee1 kinase activity. Moreover, treatment of cells with either CDK2 inhibitors or carboplatin leads to transient transcriptional induction of cyclin E (in cyclin E-low tumors) and result in DNA replicative stress. Such drug-mediated cyclin E induction in TNBC cells and PDX models sensitizes them to AZD1775 in a sequential treatment combination strategy.Conclusions: Cyclin E is a potential biomarker of response (i) for AZD1775 as monotherapy in cyclin E-high TNBC tumors and (ii) for sequential combination therapy with CDK2 inhibitor or carboplatin followed by AZD1775 in cyclin E-low TNBC tumors.

Prognostic value of immunohistochemically detected p53 in adjuvant chemotherapy-treated triple negative breast cancer

Mutations of the p53 gene are the most common genomic alterations associated with triple-negative breast cancer (TNBC) and are reported in 60-88% cases. Despite the high incidence of such mutations, there is no consensus about the clinical application of p53 detection in breast cancer management. This study investigates the prognostic value of immunohistochemically detected p53 in TNBC patients who received adjuvant chemotherapy. We reviewed the clinicopathologic features of 1088 TNBC patients who received curative surgery and adjuvant chemotherapy. Immunohistochemically, nuclear staining of >10% was defined as p53 "positive." Of the total 1088 TNBC patients, 709 (65.2%) had no lymph node metastasis (N0). Among the N0 patients, 408 (57.5%) were p53- positive (p53+), and 301 (42.5%) were p53- negative (p53-). p53 + tumors showed a tendency for better breast cancer-specific survival (BCSS, p = 0.052) and overall survival (OS, p = 0.079) compared to p53- tumors. In multivariate analysis, p53 + tumors showed significantly better BCSS (p53 + vs. p53-; HR 2.8, 95% confidence interval: 1.1-7.3, p = 0.034); however, in TNBC patients with lymph node metastasis, there was no correlation between p53 status, clinicopathologic characteristics, and survival. Consequently, in TNBC patients who received adjuvant chemotherapy, immunohistochemical p53 expression was associated with better BCSS in N0 patients.

TP53 protein levels, RNA-based pathway assessment, and race among invasive breast cancer cases

Mutations in tumor suppressor TP53 have been inconsistently linked to breast cancer risk factors and survival. Immunohistochemistry (IHC) staining, a primary clinical means of TP53 mutation determination, only detects mutations that facilitate protein accumulation (e.g., missense mutations). RNA-based pathway methods capture functional status and may aid in understanding the role of TP53 function in racial disparities of breast cancer. TP53 status was assessed among invasive breast cancer cases from the Carolina Breast Cancer Study (CBCS) (2008–2013) using IHC and an established RNA-based TP53 signature (CBCS and The Cancer Genome Atlas (TCGA)). Frequency of TP53 status (IHC, RNA-based) was estimated in association with tumor characteristics, PAM50 intrinsic subtype, age, and race using relative frequency differences (RFDs) and 95% confidence intervals (95% CI) as the measure of association. Approximately 60% of basal-like tumors were TP53 protein positive (IHC), while nearly 100% were TP53 mutant-like (RNA). Luminal A tumors had low frequency of TP53 positivity (IHC: 7.9%) and mutant-like status (RNA: 1.7%). Mutant-like TP53 (RNA) was strongly associated with age ≤50 years, high tumor grade, advanced stage of disease, large tumor size, and basal-like and HER2 intrinsic subtypes. Black race was strongly associated with TP53 mutant-like status (RNA) (RFD: 24.8%, 95% CI: 20.5, 29.0) even after adjusting for age, grade, stage (RFD: 11.3%; 95% CI: 7.6, 15.0). Associations were attenuated and non-significant when measured by IHC. IHC-based TP53 status is an insensitive measurement of TP53 functional status. RNA-based methods suggest a role for TP53 in tumor prognostic features and racial disparities.

RNA-based assays offer a more sensitive and clinically informative measure of mutations in the tumor suppressor TP53 among women with invasive breast cancer than do immunohistochemistry techniques that can only detect altered proteins. Using tumor samples from more than 1000 women enrolled in the Carolina Breast Cancer Study (CBCS), Melissa Troester from the University of North Carolina at Chapel Hill, USA, and coworkers assessed the functional status of TP53 via both classical immunohistochemistry methods and an RNA-based test of expression levels among 52 TP53-dependent genes. The results of the RNA analysis were strongly associated with younger age-of-onset, higher grade tumors, more advanced stage disease, larger tumor size, aggressive cancer subtypes and race—with more black women harboring TP53 mutant-like tumors than white women. By comparison, these associations were weaker or non-significant when using immunohistochemistry-based tests.

Complexes formed by mutant p53 and their roles in breast cancer

Breast cancer is the most frequently diagnosed malignancy in women, and mutations in the tumor suppressor p53 are commonly detected in the most aggressive subtypes. The majority of TP53 gene alterations are missense substitutions, leading to expression of mutant forms of the p53 protein that are frequently detected at high levels in cancer cells. P53 mutants not only lose the physiological tumor-suppressive activity of the wild-type p53 protein but also acquire novel powerful oncogenic functions, referred to as gain of function, that may actively confer a selective advantage during tumor progression. Some of the best-characterized oncogenic activities of mutant p53 are mediated by its ability to form aberrant protein complexes with other transcription factors or proteins not directly related to gene transcription. The set of cellular proteins available to interact with mutant p53 is dependent on cell type and extensively affected by environmental signals, so the prognostic impact of p53 mutation is complex. Specific functional interactions of mutant p53 can profoundly impact homeostasis of breast cancer cells, reprogramming gene expression in response to specific extracellular inputs or cell-intrinsic conditions. The list of protein complexes involving mutant p53 in breast cancer is continuously growing, as is the number of oncogenic phenotypes in which they could be involved. In consideration of the functional impact of such complexes, key interactions of mutant p53 may be exploited as potential targets for development of therapies aimed at defusing the oncogenic potential of p53 mutation.

ERβ alters the chemosensitivity of luminal breast cancer cells by regulating p53 function

Estrogen receptor α (ERα)-positive breast cancers tend to develop resistance to both endocrine therapy and chemotherapy. Despite recent progress in defining molecular pathways that confer endocrine resistance, the mechanisms that regulate chemotherapy response in luminal tumors remain largely elusive. Luminal tumors often express wild-type p53 that is a major determinant of the cellular DNA damage response. Similar to p53, the second ER subtype, ERβ, has been reported to inhibit breast tumorigenesis by acting alone or in collaboration with p53. However, a synergistic mechanism of action has not been described. Here, we suggest that ERβ relies on p53 to elicit its tumor repressive actions in ERα-positive breast cancer cells. Upregulation of ERβ and treatment with ERβ agonists potentiates the tumor suppressor function of p53 resulting in decreased survival. This effect requires molecular interaction between the two proteins that disrupts the inhibitory action of ERα on p53 leading to increased transcriptional activity of p53. In addition, we show that the same interaction alters the chemosensitivity of endocrine-resistant cells including their response to tamoxifen therapy. Our results suggest a collaboration of ERβ and p53 tumor suppressor activity in breast cancer cells that indicates the importance of ligand-regulated ERβ as a tool to target p53 activity and improve the clinical management of resistant disease.

18FDG-PET/CT and molecular markers to predict response to neoadjuvant chemotherapy and outcome in HER2-negative advanced luminal breast cancers patients

Background

The efficacy of neoadjuvant chemotherapy regimens in advanced luminal breast cancer patients is difficult to predict. Intrinsic properties of breast tumors, including altered gene expression profile and dynamic evaluation of metabolic properties of tumor cells using positron emission tomography/computed tomography (PET/CT) of tumor cells, have been identified to guide patient's prognosis. The aim of this study is to determine if both analyses may improve the prediction of response to neoadjuvant chemotherapy in ER-positive / HER2-negative breast cancers (BCs) patients.

Methods

We used metabolic PET parameters, at diagnosis and after two cycles of chemotherapy and proliferation gene expression profile on biopsy at diagnosis, in particular, the genomic grade index (GGI) analyzed by reverse transcription and quantitative polymerase chain reaction (RT-qPCR). The pathological response was the surrogate endpoint.

Results

The change of FDG uptake between baseline PET and interim PET after 2 cycles of neoadjuvant chemotherapy (ΔSUVmax) was highly associated with pCR (p=0.008). We also observed an ability of P53 mutated status (p=0.042), in addition to histological grade (p=0. 0004), and PR expression (p=0.01) to predict pCR in ER-positive BCs, whereas no proliferation marker predicted pCR (P=0.39 for GGI). Finally, only ΔSUVmax was significantly associated with event free survival (p=0.047).

Conclusions

Our results confirm the predictive and prognostic value of tumor ΔSUVmax in ER-positive /HER2-negative advanced BCs patients. These findings can be helpful to select high-risk patients within trials investigating novel treatment strategies.

SRC Increases MYC mRNA Expression in Estrogen Receptor-Positive Breast Cancer via mRNA Stabilization and Inhibition of p53 Function

The transcription factor gene MYC is important in breast cancer, and its mRNA is maintained at a high level even in the absence of gene amplification. The mechanism(s) underlying increased MYC mRNA expression is unknown. Here, we demonstrate that MYC mRNA was stabilized upon estrogen stimulation of estrogen receptor-positive breast cancer cells via SRC-dependent effects on a recently described RNA-binding protein, IMP1 with an N-terminal deletion (ΔN-IMP1). We also show that loss of the tumor suppressor p53 increased MYC mRNA levels even in the absence of estrogen stimulation. However, in cells with wild-type p53, SRC acted to overcome p53-mediated inhibition of estrogen-stimulated cell cycle entry and progression. SRC thus promotes cell proliferation in two ways: by stabilizing MYC mRNA and by inhibiting p53 function. Since estrogen receptor-positive breast cancers typically express wild-type p53, these studies establish a rationale for p53 status to be predictive for effective SRC inhibitor treatment in this subtype of breast cancer.

A Numb-Mdm2 fuzzy complex reveals an isoform-specific involvement of Numb in breast cancer

Numb functions as an oncosuppressor by inhibiting Notch signaling and stabilizing p53. This latter effect depends on the interaction of Numb with Mdm2, the E3 ligase that ubiquitinates p53 and commits it to degradation. In breast cancer (BC), loss of Numb results in a reduction of p53-mediated responses including sensitivity to genotoxic drugs and maintenance of homeostasis in the stem cell compartment. In this study, we show that the Numb-Mdm2 interaction represents a fuzzy complex mediated by a short Numb sequence encompassing its alternatively spliced exon 3 (Ex3), which is necessary and sufficient to inhibit Mdm2 and prevent p53 degradation. Alterations in the Numb splicing pattern are critical in BC as shown by increased chemoresistance of tumors displaying reduced levels of Ex3-containing isoforms, an effect that could be mechanistically linked to diminished p53 levels. A reduced level of Ex3-less Numb isoforms independently predicts poor outcome in BCs harboring wild-type p53. Thus, we have uncovered an important mechanism of chemoresistance and progression in p53-competent BCs.

Frequent overexpression of AMAP1, an Arf6 effector in cell invasion, is characteristic of the MMTV-PyMT rather than the MMTV-Neu human breast cancer model

Background

The small GTPase Arf6 and its downstream effector AMAP1 (also called ASAP1/DDEF1) constitute a signaling pathway promoting cell invasion, in which AMAP1 interacts with several different proteins, including PRKD2, EPB41L5, paxillin, and cortactin. Components of this pathway are often overexpressed in human breast cancer cells, to be correlated with poor prognosis of the patients, whereas overexpression of the Arf6 pathway did not correlate with the four main molecular classes of human breast tumors. In this pathway, receptor tyrosine kinases, including EGFR and Her2, activate Arf6 via GEP100. MMTV-PyMT mice and MMTV-Neu mice are well-established models of human breast cancer, and exhibit the early dissemination and the lung metastasis, by utilizing protein tyrosine phosphorylation for oncogenesis. PyMT-tumors and Neu-tumors are known to have overlapping gene expression profiles, which primarily correspond to the luminal B-type of human mammary tumors, although they differ in the time necessary for tumor onset and metastasis. Given the common usage of protein tyrosine phosphorylation, as well as the frequent use of these animal models for studying breast cancer at the molecular level, we here investigated whether mammary tumors in these mouse models utilize the Arf6-based pathway for invasion.

Methods

Expression levels of Arf6, AMAP1, and GEP100 were analyzed in PyMT-tumors and Neu-tumors by western blotting. Expression of Arf6 and AMAP1 was also analyzed by immunohistochemistry. The involvement of AMAP1 in invasion, and the possible correlation of its high expression levels with cancer mesenchymal properties were also investigated.

Results

We found that PyMT-tumors, but not Neu-tumors, frequently overexpress AMAP1 and use it for invasion, whereas both types of tumors expressed Arf6 and GEP100 at different levels. High levels of the AMAP1 expression among PyMT-tumor cells were frequently correlated with loss of the epithelial marker CK8 and also with expression of the mesenchymal marker vimentin both at the primary sites and at sites of the lung metastases.

Conclusions

PyMT-tumors appear to frequently utilize the Arf6-based invasive machinery, whereas Neu-tumors do not. Our results suggest that MMTV-PyMT mice, rather than MMTV-Neu mice, are useful to study the Arf6-based mammary tumor malignancies, as a representative model of human breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s12964-017-0212-z) contains supplementary material, which is available to authorized users.

HDAC2 and HDAC5 Up-Regulations Modulate Survivin and miR-125a-5p Expressions and Promote Hormone Therapy Resistance in Estrogen Receptor Positive Breast Cancer Cells

Intrinsic or acquired resistance to hormone therapy is frequently reported in estrogen receptor positive (ER⁺) breast cancer patients. Even though dysregulations of histone deacetylases (HDACs) are known to promote cancer cells survival, the role of different HDACs in the induction of hormone therapy resistance in ER⁺ breast cancer remains unclear. Survivin is a well-known pro-tumor survival molecule and miR-125a-5p is a recently discovered tumor suppressor. In this study, we found that ER⁺, hormone-independent, tamoxifen-resistant MCF7-TamC3 cells exhibit increased expression of HDAC2, HDAC5, and survivin, but show decreased expression of miR-125a-5p, as compared to the parental tamoxifen-sensitive MCF7 breast cancer cells. Molecular down-regulations of HDAC2, HDAC5, and survivin, and ectopic over-expression of miR-125a-5p, increased the sensitivity of MCF7-TamC3 cells to estrogen deprivation and restored the sensitivity to tamoxifen. The same treatments also further increased the sensitivity to estrogen-deprivation in the ER⁺ hormone-dependent ZR-75-1 breast cancer cells in vitro. Kaplan-Meier analysis and receiver operating characteristic curve analysis of expression cohorts of breast tumor showed that high HDAC2 and survivin, and low miR-125a-5p, expression levels correlate with poor relapse-free survival in endocrine therapy and tamoxifen-treated ER⁺ breast cancer patients. Further molecular analysis revealed that HDAC2 and HDAC5 positively modulates the expression of survivin, and negatively regulates the expression miR-125a-5p, in ER⁺ MCF7, MCF7-TamC3, and ZR-75-1 breast cancer cells. These findings indicate that dysregulations of HDAC2 and HDAC5 promote the development of hormone independency and tamoxifen resistance in ERC breast cancer cells in part through expression regulation of survivin and miR-125a-5p.

Pre-clinical validation of a selective anti-cancer stem cell therapy for Numb-deficient human breast cancers

The cell fate determinant Numb is frequently downregulated in human breast cancers (BCs), resulting in p53 inactivation and an aggressive disease course. In the mouse mammary gland, Numb/p53 downregulation leads to aberrant tissue morphogenesis, expansion of the stem cell compartment, and emergence of cancer stem cells (CSCs). Strikingly, CSC phenotypes in a Numb-knockout mouse model can be reverted by Numb/p53 restoration. Thus, targeting Numb/p53 dysfunction in Numb-deficient human BCs could represent a novel anti-CSC therapy. Here, using patient-derived xenografts, we show that expansion of the CSC pool, due to altered self-renewing divisions, is also a feature of Numb-deficient human BCs. In these cancers, using the inhibitor Nutlin-3 to restore p53, we corrected the defective self-renewal properties of Numb-deficient CSCs and inhibited CSC expansion, with a marked effect on tumorigenicity and metastasis. Remarkably, a regimen combining Nutlin-3 and chemotherapy induced persistent tumor growth inhibition, or even regression, and prevented CSC-driven tumor relapse after removal of chemotherapy. Our data provide a pre-clinical proof-of-concept that targeting Numb/p53 results in a specific anti-CSC therapy in human BCs.

PLA2G7 associates with hormone receptor negativity in clinical breast cancer samples and regulates epithelial-mesenchymal transition in cultured breast cancer cells

Breast cancer is the leading cause of cancer‐related deaths in women due to distinct cancer subtypes associated with early recurrence and aggressive metastatic progression. High lipoprotein‐associated phospholipase A2 (PLA2G7) expression has previously been associated with aggressive disease and metastasis in prostate cancer. Here, we explore the expression pattern and functional role of PLA2G7 in breast cancer. First, a bioinformatic analysis of genome‐wide gene expression data from 970 breast samples was carried out to evaluate the expression pattern of PLA2G7 mRNA in breast cancer. Second, the expression profile of PLA2G7 was studied in 1042 breast cancer samples including 89 matched lymph node metastasis samples using immunohistochemistry. Third, the effect of PLA2G7 silencing on genome‐wide gene expression profile was studied and validated in cultured breast cancer cells expressing PLA2G7 at high level. Last, the expression pattern of PLA2G7 mRNA was investigated in 24 nonmalignant tissue samples and 65 primary and 7 metastatic tumour samples derived from various organs using qRT‐PCR. The results from clinical breast cancer samples indicated that PLA2G7 is overexpressed in a subset of breast cancer samples compared to its expression in benign breast tissue samples and that high PLA2G7 expression associated with hormone receptor negativity as well as with poor prognosis in a subset of breast cancer samples. In vitro functional studies highlighted the putative role of PLA2G7 in the regulation of epithelial‐mesenchymal transition (EMT)‐related signalling pathways, vimentin and E‐cadherin protein expression as well as cell migration in cultured breast cancer cells. Furthermore, supporting the findings in breast and prostate cancer, high PLA2G7 mRNA expression was associated with metastatic cancer in four additional organs of origin. In conclusion, our results indicate that PLA2G7 is highly expressed in a subset of metastatic and aggressive breast cancers and in metastatic samples of various tissues of origin and promotes EMT and migration in cultured breast cancer cells.

Salivary Duct Carcinoma: An Update on Morphologic Mimics and Diagnostic Use of Androgen Receptor Immunohistochemistry

More than 15 years ago, seminal studies by Dr. E. Leon Barnes and colleagues transformed our understanding of salivary duct carcinoma (SDC) and, in doing so, paved the way for contemporary diagnostic and therapeutic approaches to this aggressive salivary adenocarcinoma. In particular, attention to the apocrine phenotype of SDC and expression of androgen receptor (AR) by immunohistochemistry has improved the diagnostic accuracy and showed how SDC can be reliably distinguished from its morphologic mimics (i.e., other salivary gland carcinomas with high grade transformation, low grade cribriform cystadenocarcinoma, and squamous cell carcinomas involving parotid). Furthermore, the observation that SDC shares AR expression with prostate cancer and apocrine breast cancer foresaw the discovery of common molecular alterations between SDC and these tumor types and draw attention to androgen deprivation therapy for SDC patients.

P53 and Ki-67 as prognostic markers in triple-negative breast cancer patients

Triple-negative breast cancer (TNBC) is an aggressive subgroup of breast cancer lack of effective target therapy. This study was to investigate the prognostic role of p53 and Ki-67 in 156 cases of TNBC patients. Logistic regression analysis was used to examine the association between clinical parameters and recurrence. Univariate and multivariate analyses were used to examine the association between clinical characteristics and disease-free survival (DFS) or overall survival (OS). Survival analyses using the Kaplan-Meier method were performed to examine the association between p53/Ki-67 and DFS and OS. Our data showed that p53 was positive in 71.3% and the Ki-67 high index was in 82.8% of TNBC. Elevated p53 and Ki-67 were associated with histological grade. The tumor size, lymph node involvement, and p53 expression are associated with risk of recurrence. Tumor size, lymph node involvement, family history, Ki-67 and p53 are independent variables associated with either DFS or OS. TNBC patients with positive p53 or Ki-67 high index or family history of cancer have a significant association with worse prognosis. This study suggests that p53, Ki-67 and family history are useful prognostic markers in TNBC.

Emerging Non-Canonical Functions and Regulation by p53: p53 and Stemness

Since its discovery nearly 40 years ago, p53 has ascended to the forefront of investigated genes and proteins across diverse research disciplines and is recognized most exclusively for its role in cancer as a tumor suppressor. Levine and Oren (2009) reviewed the evolution of p53 detailing the significant discoveries of each decade since its first report in 1979. In this review, we will highlight the emerging non-canonical functions and regulation of p53 in stem cells. We will focus on general themes shared among p53's functions in non-malignant stem cells and cancer stem-like cells (CSCs) and the influence of p53 on the microenvironment and CSC niche. We will also examine p53 gain of function (GOF) roles in stemness. Mutant p53 (mutp53) GOFs that lead to survival, drug resistance and colonization are reviewed in the context of the acquisition of advantageous transformation processes, such as differentiation and dedifferentiation, epithelial-to-mesenchymal transition (EMT) and stem cell senescence and quiescence. Finally, we will conclude with therapeutic strategies that restore wild-type p53 (wtp53) function in cancer and CSCs, including RING finger E3 ligases and CSC maintenance. The mechanisms by which wtp53 and mutp53 influence stemness in non-malignant stem cells and CSCs or tumor-initiating cells (TICs) are poorly understood thus far. Further elucidation of p53's effects on stemness could lead to novel therapeutic strategies in cancer research.

p53 deficiency induces cancer stem cell pool expansion in a mouse model of triple-negative breast tumors

Triple-negative breast cancer is a heterogeneous disease characterized by the expression of basal cell markers, no estrogen or progesterone receptor expression and a lack of HER2 overexpression. Triple-negative tumors often display activated Wnt/β-catenin signaling and most have impaired p53 function. We studied the interplay between p53 loss and Wnt/β-catenin signaling in stem cell function and tumorigenesis, by deleting p53 from the mammary epithelium of K5ΔNβcat mice displaying a constitutive activation of Wnt/β-catenin signaling in basal cells. K5ΔNβcat transgenic mice present amplification of the basal stem cell pool and develop triple-negative mammary carcinomas. The loss of p53 in K5ΔNβcat mice led to an early expansion of mammary stem/progenitor cells and accelerated the formation of triple-negative tumors. In particular, p53-deficient tumors expressed high levels of integrins and extracellular matrix components and were enriched in cancer stem cells. They also overexpressed the tyrosine kinase receptor Met, a feature characteristic of human triple-negative breast tumors. The inhibition of Met kinase activity impaired tumorsphere formation, demonstrating the requirement of Met signaling for cancer stem cell growth in this model. Human basal-like breast cancers with predicted mutated p53 status had higher levels of MET expression than tumors with wild-type p53. These results connect p53 loss and β-catenin activation to stem cell regulation and tumorigenesis in triple-negative cancer and highlight the role of Met signaling in maintaining cancer stem cell properties, revealing new cues for targeted therapies.

The Role of the p53 Protein in Stem-Cell Biology and Epigenetic Regulation

The p53 protein plays a passive and an active role in stem cells. The transcriptional activities of p53 for cell-cycle arrest and DNA repair are largely turned off in stem cells, but there is some indication that long-term stem-cell viability may require other p53-regulated functions. When p53 is activated in stem cells, it stops cell division and promotes the commitment to a differentiation pathway and the formation of progenitor cells. In the absence of any p53 activity, stem-cell replication continues and mistakes in the normal epigenetic pathway occur at a higher probability. In the presence of a functionally active p53 protein, epigenetic stability is enforced and stem-cell replication is regulated by commitment to differentiation. Over a lifetime of an organism, stem-cell clones compete in a tissue niche for Darwinian replicative advantages and in doing so accumulate mutations that permit stem-cell replication. Mutations in the p53 gene give stem cells this advantage, increase the clonal stem-cell population, and lower the age at which cancers can occur. Li-Fraumeni patients that inherit p53 mutations develop tumors in a tissue-type-specific fashion at younger ages. Throughout the life of a Li-Fraumeni patient, the tumor types that arise occur in tissues where stem cells are active and cell division is most rapid. Thus, p53 mutations that are inherited or occur during developmental life act in stem cells of the mesenchymal and epithelial lineages, whereas p53 mutations that occur in progenitor or differentiated (somatic) cells later in life function in tissues of endodermal origins, indicating that p53 may function differently in different developmental lineages.

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.

Current Management Strategies in Breast Cancer by Targeting Key Altered Molecular Players

Breast cancer is the second largest disease affecting women worldwide. It remains the most frequently reported and leading cause of death among women in both developed and developing countries. Tamoxifen and raloxifene are commonly used selective estrogen receptor modulators for treatment of breast cancer in women with high risk, although resistance occurs by tamoxifen after 5 years of therapy and both drugs cause uterine cancer and thromboembolic events. Aromatase inhibitors (AIs) are one of the optional modes used for breast cancer treatment. The combination of AIs along with tamoxifen can also be beneficial. Various therapeutic agents from different sources are being studied, which further need to be improved for potential outcome. For this, clinical trials based on large number of patients with optimal dose and lesser side effects have to be more in practice. Despite the clinical trials going on, there is need of better molecular models, which can identify high risk population, new agents with better benefit having less side effects, and improved biomarkers for treating breast cancer.

p53 deficiency linked to B cell translocation gene 2 (BTG2) loss enhances metastatic potential by promoting tumor growth in primary and metastatic sites in patient-derived xenograft (PDX) models of triple-negative breast cancer

Background

Despite advances in early diagnosis and treatment of cancer patients, metastasis remains the major cause of mortality. TP53 is one of the most frequently mutated genes in human cancer, and these alterations can occur during the early stages of oncogenesis or as later events as tumors progress to more aggressive forms. Previous studies have suggested that p53 plays a role in cellular pathways that govern metastasis. To investigate how p53 deficiency contributes to late-stage tumor growth and metastasis, we developed paired isogenic patient-derived xenograft (PDX) models of triple-negative breast cancer (TNBC) differing only in p53 status for longitudinal analysis.

Methods

Patient-derived isogenic human tumor lines differing only in p53 status were implanted into mouse mammary glands. Tumor growth and metastasis were monitored with bioluminescence imaging, and circulating tumor cells (CTCs) were quantified by flow cytometry. RNA-Seq was performed on p53-deficient and p53 wild-type tumors, and functional validation of a lead candidate gene was performed in vivo.

Results

Isogenic p53 wild-type and p53-deficient tumors metastasized out of mammary glands and colonized distant sites with similar frequency. However, p53-deficient tumors metastasized earlier than p53 wild-type tumors and grew faster in both primary and metastatic sites as a result of increased proliferation and decreased apoptosis. In addition, greater numbers of CTCs were detected in the blood of mice engrafted with p53-deficient tumors. However, when normalized to tumor mass, the number of CTCs isolated from mice bearing parental and p53-deficient tumors was not significantly different. Gene expression profiling followed by functional validation identified B cell translocation gene 2 (BTG2), a downstream effector of p53, as a negative regulator of tumor growth both at primary and metastatic sites. BTG2 expression status correlated with survival of TNBC patients.

Conclusions

Using paired isogenic PDX-derived metastatic TNBC cells, loss of p53 promoted tumor growth and consequently increased tumor cell shedding into the blood, thus enhancing metastasis. Loss of BTG2 expression in p53-deficient tumors contributed to this metastatic potential by enhancing tumor growth in primary and metastatic sites. Furthermore, clinical data support conclusions generated from PDX models and indicate that BTG2 expression is a candidate prognostic biomarker for TNBC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0673-9) contains supplementary material, which is available to authorized users.

Identification of a new class of natural product MDM2 inhibitor: In vitro and in vivo anti-breast cancer activities and target validation

The MDM2 oncogene has been suggested as a molecular target for treating human cancers, including breast cancer. Most MDM2 inhibitors under development are targeting the MDM2-p53 binding, and have little or no effects on cancers without functional p53, such as advanced breast cancer. The present study was designed to develop a new class of MDM2 inhibitors that exhibit anticancer activity in MDM2-dependent and p53-independent manners. The selective MDM2 inhibitors were discovered by a computational structure-based screening, yielding a lead compound, termed JapA. We further found that JapA inhibited cell growth, decreased cell proliferation, and induced G2/M phase arrest and apoptosis in breast cancer cells through an MDM2-dependent mechanism, regardless of p53 status. It also inhibited the tumor growth and lung metastasis in breast cancer xenograft models without causing any host toxicity. Furthermore, JapA directly bound to MDM2 protein and reduced MDM2 levels in cancer cells in vitro and in vivo by promoting MDM2 protein degradation and inhibiting MDM2 transcription, which is distinct from the existing MDM2 inhibitors. In conclusion, JapA represents a new class of MDM2 inhibitor that exerts its anticancer activity through directly down-regulating MDM2, and might be developed as a novel cancer therapeutic agent.

High Expression of Three-Gene Signature Improves Prediction of Relapse-Free Survival in Estrogen Receptor-Positive and Node-Positive Breast Tumors

The objective of the present study was to validate prognostic gene signature for estrogen receptor alpha-positive (ER03B1+) and lymph node (+) breast cancer for improved selection of patients for adjuvant therapy. In our previous study, we identified a group of seven genes (GATA3, NTN4, SLC7A8, ENPP1, MLPH, LAMB2, and PLAT) that show elevated messenger RNA (mRNA) expression levels in ERα (+) breast cancer patient samples. The prognostic values of these genes were evaluated using gene expression data from three public data sets of breast cancer patients (n = 395). Analysis of ERα (+) breast cancer cohort (n = 195) showed high expression of GATA3, NTN4, and MLPH genes significantly associated with longer relapse-free survival (RFS). Next cohort of ERα (+) and node (+) samples (n = 109) revealed high mRNA expression of GATA3, SLC7A8, and MLPH significantly associated with longer RFS. Multivariate analysis of combined three-gene signature for ERα (+) cohort, and ERα (+) and node (+) cohorts showed better hazard ratio than individual genes. The validated three-gene signature sets for ERα (+) cohort, and ERα (+) and node (+) cohort may have potential clinical utility since they demonstrated predictive and prognostic ability in three independent public data sets.

Adiposity is associated with p53 gene mutations in breast cancer

Mutations in the p53 gene are among the most frequent genetic events in human cancer and may be triggered by environmental and occupational exposures. We examined the association of clinical and pathological characteristics of breast tumors and breast cancer risk factors according to the prevalence and type of p53 mutations. Using tumor blocks from incident cases from a case-control study in western New York, we screened for p53 mutations in exons 2-11 using the Affymetrix p53 Gene Chip array and analyzed case-case comparisons using logistic regression. The p53 mutation frequency among cases was 28.1 %; 95 % were point mutations (13 % of which were silent) and the remainder were single base pair deletions. Sixty seven percent of all point mutations were transitions; 24 % of them are G:C>A:T at CpG sites. Positive p53 mutation status was associated with poorer differentiation (OR, 95 % CI 2.29, 1.21-4.32), higher nuclear grade (OR, 95 % CI 1.99, 1.22-3.25), and increased Ki-67 status (OR, 95 % CI 1.81, 1.10-2.98). Cases with P53 mutations were more likely to have a combined ER-positive and PR-negative status (OR, 95 % CI 1.65, 1.01-2.71), and a combined ER-negative and PR-negative status (OR, 95 % CI 2.18, 1.47-3.23). Body mass index >30 kg/m(2), waist circumference >79 cm, and waist-to-hip ratio >0.86 were also associated with p53 status; obese breast cancer cases are more likely to have p53 mutations (OR, 95 % CI 1.78, 1.19-2.68). We confirmed that p53 mutations are associated with less favorable tumor characteristics and identified an association of p53 mutation status and adiposity.