Inflammatory breast cancer biomarkers and biology.

Inflammatory breast cancer (IBC) is a unique breast cancer with a highly virulent course and low 5- and 10-year survival rates. Even though it only accounts for 1-5% of breast cancers it is estimated to account for 10% of breast cancer deaths annually in the United States. The accuracy of diagnosis and classification of this unique cancer is a major concern within the medical community. Early molecular and biological studies incidentally included IBC samples with other conventional breast cancers and were not informative as to the unique nature of the disease. Subsequent molecular studies that focused specifically on IBC demonstrated that IBC has a unique biology different from other forms of breast cancer. Additionally, a handful of unique signature genes that are hallmarks of IBC have also been suggested. Further understanding of IBC biology can help with diagnosis and treatment of the disease. The current article reviews the history and highlights of IBC studies.

Deciphering the molecular biology of inflammatory breast cancer through molecular characterization of patient samples and preclinical models.

Inflammatory breast cancer is an aggressive subtype of breast cancer with dismal patient prognosis and a unique clinical presentation. In the past two decades, molecular profiling technologies have been used in order to gain insight into the molecular biology of IBC and to search for possible targets for treatment. Although a gene signature that accurately discriminates between IBC and nIBC patient samples and preclinical models was identified, the overall genomic and transcriptomic differences are small and ambiguous, mainly due to the limited sample sizes of the evaluated patient series and the failure to correct for confounding effects of the molecular subtypes. Nevertheless, data collected over the past 20 years by independent research groups increasingly support the existence of several IBC-specific biological characteristics. In this review, these features are classified as established, emerging and conceptual hallmarks based on the level of evidence reported in the literature. In addition, a synoptic model is proposed that integrates all hallmarks and that can explain how cancer cell intrinsic mechanisms (i.e. NF-κB activation, genomic instability, MYC-addiction, TGF-ß resistance, adaptive stress response, chromatin remodeling, epithelial-to-mesenchymal transition) can contribute to the establishment of the dynamic immune microenvironment associated with IBC. It stands to reason that future research projects are needed to further refine (parts of) this model and to investigate its clinical translatability.

Mutational landscape of inflammatory breast cancer.

BACKGROUND: Inflammatory breast cancer (IBC) is the most pro-metastatic form of BC. Better understanding of its enigmatic pathophysiology is crucial. We report here the largest whole-exome sequencing (WES) study of clinical IBC samples. METHODS: We retrospectively applied WES to 54 untreated IBC primary tumor samples and matched normal DNA. The comparator samples were 102 stage-matched non-IBC samples from TCGA. We compared the somatic mutational profiles, spectra and signatures, copy number alterations (CNAs), HRD and heterogeneity scores, and frequencies of actionable genomic alterations (AGAs) between IBCs and non-IBCs. The comparisons were adjusted for the molecular subtypes. RESULTS: The number of somatic mutations, TMB, and mutational spectra were not different between IBCs and non-IBCs, and no gene was differentially mutated or showed differential frequency of CNAs. Among the COSMIC signatures, only the age-related signature was more frequent in non-IBCs than in IBCs. We also identified in IBCs two new mutational signatures not associated with any environmental exposure, one of them having been previously related to HIF pathway activation. Overall, the HRD score was not different between both groups, but was higher in TN IBCs than TN non-IBCs. IBCs were less frequently classified as heterogeneous according to heterogeneity H-index than non-IBCs (21% vs 33%), and clonal mutations were more frequent and subclonal mutations less frequent in IBCs. More than 50% of patients with IBC harbored at least one high-level of evidence (LOE) AGA (OncoKB LOE 1-2, ESCAT LOE I-II), similarly to patients with non-IBC. CONCLUSIONS: We provide the largest mutational landscape of IBC. Only a few subtle differences were identified with non-IBCs. The most clinically relevant one was the higher HRD score in TN IBCs than in TN non-IBCs, whereas the most intriguing one was the smaller intratumor heterogeneity of IBCs.

A Subpopulation of Luminal Progenitors Secretes Pleiotrophin to Promote Angiogenesis and Metastasis in Inflammatory Breast Cancer.

Inflammatory breast cancer (IBC) is a highly aggressive subtype of breast cancer characterized by rapidly arising diffuse erythema and edema. Genomic studies have not identified consistent alterations and mechanisms that differentiate IBC from non-IBC tumors, suggesting that the microenvironment could be a potential driver of IBC phenotypes. Here, using single-cell RNA sequencing, multiplex staining, and serum analysis in patients with IBC, we identified enrichment of a subgroup of luminal progenitor (LP) cells containing high expression of the neurotropic cytokine pleiotrophin (PTN) in IBC tumors. PTN secreted by the LP cells promoted angiogenesis by directly interacting with the NRP1 receptor on endothelial tip cells located in both IBC tumors and the affected skin. NRP1 activation in tip cells led to recruitment of immature perivascular cells in the affected skin of IBC, which are correlated with increased angiogenesis and IBC metastasis. Together, these findings reveal a role for cross-talk between LPs, endothelial tip cells, and immature perivascular cells via PTN-NRP1 axis in the pathogenesis of IBC, which could lead to improved strategies for treating IBC. SIGNIFICANCE: Nonmalignant luminal progenitor cells expressing pleiotrophin promote angiogenesis by activating NRP1 and induce a prometastatic tumor microenvironment in inflammatory breast cancer, providing potential therapeutic targets for this aggressive breast cancer subtype.

Dysregulated Stem Cell Markers Musashi-1 and Musashi-2 are Associated with Therapy Resistance in Inflammatory Breast Cancer.

BACKGROUND AND AIM: While preliminary evidence points to pro-tumorigenic roles for the Musashi (MSI) RNA-binding proteins Musashi-1 (MSI1) and Musashi-2 (MSI2) in some breast cancer subtypes, no data exist for inflammatory breast cancer (IBC). METHODS: MSI gene expression was quantified in IBC SUM149PT cells. We then used small interfering RNA-based MSI1 and MSI2 double knockdown (DKD) to understand gene expression and functional changes upon MSI depletion. We characterized cancer stem cell characteristics, cell apoptosis and cell cycle progression via flow cytometry, mammospheres via spheroid assays, migration and proliferation via digital holographic microscopy, and cell viability using BrdU assays. Chemoresistance was determined for paclitaxel and cisplatin with MTT assays and radioresistance was assessed with clonogenic analyses. In parallel, we supported our in vitro data by analyzing publicly available patient IBC gene expression datasets. RESULTS: MSI1 and MSI2 are upregulated in breast cancer generally and IBC specifically. MSI2 is more commonly expressed compared to MSI1. MSI DKD attenuated proliferation, cell cycle progression, migration, and cell viability while increasing apoptosis. Stem cell characteristics CD44(+)/CD24(-), TERT and Oct4 were associated with MSI expression in vivo and were decreased in vitro after MSI DKD as was ALDH expression and mammosphere formation. In vivo, chemoresistant tumors were characterized by MSI upregulation upon chemotherapy application. In vitro, MSI DKD was able to alleviate chemo- and radioresistance. CONCLUSIONS: The Musashi RNA binding proteins are dysregulated in IBC and associated with tumor proliferation, cancer stem cell phenotype, chemo- and radioresistance. MSI downregulation alleviates therapy resistance and attenuates tumor proliferation in vitro.

Copy Number Variation in Inflammatory Breast Cancer.

Identification of a unique genomic biomarker in de novo inflammatory breast cancer (IBC) may provide an insight into the biology of this aggressive disease. The goal of our study was to elucidate biomarkers associated with IBC. We examined breast biopsies collected from Dana-Farber Cancer Institute patients with IBC prior to initiating preoperative systemic treatment (30 samples were examined, of which 14 were eligible). Patients without available biopsies (n = 1), with insufficient tumor epithelial cells (n = 10), or insufficient DNA yield (n = 5) were excluded from the analysis. Molecular subtype and tumor grade were abstracted from a medical records' review. Ten IBC tumors were estrogen-receptor-positive (ER+) and human epidermal growth factor receptor 2 (HER2)-negative (n = 10 out of 14). Sufficient RNA and DNA were simultaneously extracted from 14 biopsy specimens using the Qiagen AllPrep Kit. RNA was amplified using the Sensation kit and profiled using the Affymetrix Human Transcriptome Array 2.0. DNA was profiled for genome-wide copy number variation (CNV) using the Affymetrix OncoScan Array and analyzed using the Nexus Chromosome Analysis Suite. Among the 14 eligible samples, we first confirmed biological concordance and quality control metrics using replicates and gene expression data. Second, we examined CNVs and gene expression change by IBC subtype. We identified significant CNVs in IBC patients after adjusting for multiple comparisons. Next, to assess whether the CNVs were unique to IBC, we compared the IBC CNV data to fresh-frozen non-IBC CNV data from The Cancer Genome Atlas (n = 388). On chromosome 7p11.2, we identified significant CN gain located at position 58,019,983-58,025,423 in 8 ER+ IBC samples compared to 338 non-IBC ER+ samples (region length: 5440 bp gain and 69,039 bp, False Discovery Rate (FDR) p-value = 3.12 × 10-10) and at position 57,950,944-58,025,423 in 3 TN-IBC samples compared to 50 non-IBC TN samples (74,479 base pair, gain, FDR p-value = 4.27 × 10-5; near the EGFR gene). We also observed significant CN loss on chromosome 21, located at position 9,648,315-9,764,385 (p-value = 4.27 × 10-5). Secondarily, differential gene expression in IBC patients with 7p11.2 CN gain compared to SUM149 were explored after FDR correction for multiple testing (p-value = 0.0016), but the results should be interpreted with caution due to the small sample size. Finally, the data presented are hypothesis-generating. Validation of CNVs that contribute to the unique presentation and biological features associated with IBC in larger datasets may lead to the optimization of treatment strategies.

Differential Gene Expression of fresh tissue and patient-derived explants' matricellular proteins augment inflammatory breast cancer metastasis: the possible role of IL-6 and MCP-1.

BACKGROUND: Matricellular proteins comprising matrisome and adhesome are responsible for structure integrity and interactions between cells in the tumour microenvironment of breast cancer. Changes in the gene expression of matrisome and adhesome augment metastasis. Since inflammatory breast cancer (IBC) is characterized by high metastatic behaviour. Herein, we compared the gene expression profile of matrisome and adhesome in non-IBC and IBC in fresh tissue and ex vivo patient-derived explants (PDEs) and we also compared the secretory inflammatory mediators of PDEs in non-IBC and IBC to identify secretory cytokines participate in cross-talk between cells via interactions with matrisome and adhisome. METHODS: Fifty patients (31 non-IBC and 19 IBC) were enrolled in the present study. To test their validation in clinical studies, PDEs were cultured as an ex vivo model. Gene expression and cytokine array were used to identify candidate genes and cytokines contributing to metastasis in the examined fresh tissues and PDEs. Bioinformatics analysis was applied on identified differentially expressed genes using GeneMANIA and Metascape gene annotation and analysis resource to identify pathways involved in IBC metastasis. RESULTS: Normal and cancer fresh tissues and PDEs of IBC were characterized by overexpression of CDH1 and MMP14 and downregulation of CTNNA1 and TIMP1 compared with non-IBC. The secretome of IBC cancer PDEs is characterized by significantly high expression of interleukin 6 and monocyte chemoattractant protein-1 (CCL2) compared with non-IBC. CONCLUSION: Genes expressed by adhisome and matrisome play a significant role in IBC metastasis and should be considered novel target therapy.

Synchrotron Fourier-Transform Infrared Microspectroscopy: Characterization of in vitro polarized tumor-associated macrophages stimulated by the secretome of inflammatory and non-inflammatory breast cancer cells.

Studies suggested that the pathogenesis of inflammatory breast cancer (IBC) is related to inflammatory manifestations accompanied by specific cellular and molecular mechanisms in the IBC tumor microenvironment (TME). IBC is characterized by significantly higher infiltration of tumor-associated macrophages (TAMs) that contribute to its metastatic process via secreting many cytokines such as TNF, IL-6, IL-8, and IL-10 that enhance invasion and angiogenesis. Thus, there is a need to first understand how IBC-TME modulates the polarization of TAMs to better understand the role of TAMs in IBC. Herein, we used gene expression signature and Synchrotron Fourier-Transform Infrared Microspectroscopy (SR-µFTIR) to study the molecular and biochemical changes, respectively of in vitro polarized TAMs stimulated by the secretome of IBC and non-IBC cells. The gene expression signature showed significant differences in the macrophage's polarization-related genes between stimulated TAMs. FTIR spectra showed absorption bands in the region of 1700-1500 cm-1 attributed to the amide I ν(C=O), & νAS (CN), δ (NH), and amide II ν(CN), δ (NH) proteins bands. Moreover, three peaks of different intensities and areas were detected in the lipid region of the νCH2 and νCH3 stretching modes positioned within the 3000-2800 cm-1 range. The PCA analysis for the second derivative spectra of the amide regions discriminates between stimulated IBC and non-IBC TAMs. This study showed that IBC and non-IBC TMEs differentially modulate the polarization of TAMs and SR-µFTIR can determine these biochemical changes which will help to better understand the potential role of TAMs in IBC.

HER2-low inflammatory breast cancer: Clinicopathologic features and prognostic implications.

BACKGROUND: HER2)-low expression is a predictive biomarker for novel anti-HER2 antibody-drug conjugates. However, little is known about its clinical significance in inflammatory breast cancer (IBC). METHODS: Patients diagnosed with HER2-negative IBC between December 1999 and December 2020 were identified from the Dana-Farber Cancer Institute IBC registry. Patients were divided into HER2-low (IHC 1+ or 2+/ISH-) and HER2-zero (IHC 0), comparing clinicopathologic features and disease outcomes between the two subgroups. RESULTS: The study included 276 patients. Among patients with stage III (n = 209) and stage IV (n = 67) IBC, 54% and 39% had HER2-low tumours, respectively. Oestrogen receptor (ER)-expressing tumours were more common in patients with HER2-low versus HER2-zero stage III IBC (65% versus 38%, p < 0.01). Among stage III patients undergoing surgery (n = 182), pathologic complete response (pCR) rates were higher for HER2-zero versus HER2-low IBC (11% versus 6%, OR: 1.8, 95%CI:0.6-5.3), but minimal differences persisted when separately analysing pCR by ER status. Similar invasive disease-free survival (iDFS) outcomes were observed among ER-positive HER2-zero versus HER2-low IBC (48-month iDFS: 63% versus 63%, HR: 1.10, 95%CI:0.57-2.13) and ER-negative HER2-zero versus HER2-low IBC (48-month iDFS: 28% versus 25%, HR: 1.19, 95%CI:0.69-2.04). Differences in overall survival (OS) were small, both among ER-positive HER2-zero versus HER2-low IBC (48-month OS: 80% versus 81%, HR: 0.82, 95%CI:0.39-1.73) and ER-negative HER2-zero versus HER2-low IBC (48-month OS: 34% versus 47%, HR: 1.34, 95%CI: 0.74-2.41). CONCLUSIONS: Marginal differences in clinicopathologic features and outcomes were observed in HER2-low versus HER2-zero IBC when controlling for ER status, not supporting the definition of HER2-low as a distinct subtype of IBC.

Role of adipose tissue-derived cytokines in the progression of inflammatory breast cancer in patients with obesity.

BACKGROUND: Inflammatory breast cancer (IBC) represents a deadly aggressive phenotype of breast cancer (BC) with a unique clinicopathological presentation and low survival rate. In fact, obesity represents an important risk factor for BC. Although several studies have identified different cellular-derived and molecular factors involved in IBC progression, the role of adipocytes remains unclear. Cancer-associated adipose tissue (CAAT) expresses a variety of adipokines, which contribute to tumorigenesis and the regulation of cancer stem cell (CSC). This research investigated the potential effect of the secretome of CAAT explants from patients with BC on the progression and metastasis of the disease. METHODS: This study established an ex-vivo culture of CAAT excised from IBC (n = 13) vs. non-IBC (n = 31) patients with obesity and profiled their secretome using a cytokine antibody array. Furthermore, the quantitative PCR (qPCR) methodology was used to validate the levels of predominant cytokines at the transcript level after culture in a medium conditioned by CAAT. Moreover, the impact of the CAAT secretome on the expression of epithelial-mesenchymal transition (EMT) and cells with stem cell (CSC) markers was studied in the non-IBC MDA-MB-231 and the IBC SUM-149 cell lines. The statistical differences between variables were evaluated using the chi-squared test and unpaired a Student's t-test. RESULTS: The results of cytokine array profiling revealed an overall significantly higher level of a panel of 28 cytokines secreted by the CAAT ex-vivo culture from IBC patients with obesity compared to those with non-IBC. Of note, interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemo-attractant protein 1 (MCP-1) were the major adipokines secreted by the CAAT IBC patients with obesity. Moreover, the qPCR results indicated a significant upregulation of the IL-6, IL-8, and MCP-1 mRNAs in CAAT ex-vivo culture of patients with IBC vs. those with non-IBC. Intriguingly, a qPCR data analysis showed that the CAAT secretome secretions from patients with non-IBC downregulated the mRNA levels of the CD24 CSC marker and of the epithelial marker E-cadherin in the non-IBC cell line. By contrast, E-cadherin was upregulated in the SUM-149 cell. CONCLUSIONS: This study identified the overexpression of IL-6, IL-8, and MCP-1 as prognostic markers of CAAT from patients with IBC but not from those with non-IBC ; moreover, their upregulation might be associated with IBC aggressiveness via the regulation of CSC and EMT markers. This study proposed that targeting IL-6, IL-8, and MCP-1 may represent a therapeutic option that should be considered in the treatment of patients with IBC.

Prognostic factors in inflammatory breast cancer: A single-center study.

BACKGROUND: Previous studies have shown that poor prognostic indicators of inflammatory breast cancer (IBC) include younger age at diagnosis, poorer tumor grade, negative estrogen receptor, lesser degree of pathological response in the breast and lymph nodes. METHODS: This is a retrospective study conducted over a period of 12 years between January 2008 and December 2019 at the medical oncology department at Habib Bourguiba University Hospital in Sfax. We included in this study women with confirmed IBC. We excluded patients with no histological evidence, those whose medical records were unusable. Data collection was done from patient files. The aim of this study was to analyze the factors of poor prognosis of this entity. RESULTS: During a period of 12 years (2008-2019), 2879 cases of breast cancer were treated at Habib Bourguiba hospital in Sfax. 81 IBC were included. The incidence of IBC was 3%. The average age was 52.4 years (26-87 years). Invasive ductal carcinoma was the most frequent histological type (85.7%). Hormone receptor were positive in 64%. Human Epidermal Growth Factor Receptor-2 (HER2) was overexpressed in 35.9% of cases. The proliferation index Ki-67 was analyzed in 34 cases. It was >20% in 24 cases. Luminal A, luminal B, HER2+++, triple negative were found in 13%, 50.7%, 16% and 20% respectively. Metastases at diagnosis were found in 38%. Poor prognostic factors significantly influencing overall survival in univariate analysis were metastatic stage, high SBR grade, lymph node involvement, in particular greater than 3 nodes, negative hormone receptors, triple-negative molecular profile and occurrence of relapse. CONCLUSION: Number of positive lymph nodes greater than 3 and the occurrence of relapse were independent prognostic factors in case of localized IBC. Metastatic stage was associated with a very poor prognosis.

High endogenous CCL2 expression promotes the aggressive phenotype of human inflammatory breast cancer.

Inflammatory Breast Cancer (IBC) is a highly aggressive malignancy with distinct clinical and histopathological features whose molecular basis is unresolved. Here we describe a human IBC cell line, A3250, that recapitulates key IBC features in a mouse xenograft model, including skin erythema, diffuse tumor growth, dermal lymphatic invasion, and extensive metastases. A3250 cells express very high levels of the CCL2 chemokine and induce tumors enriched in macrophages. CCL2 knockdown leads to a striking reduction in macrophage densities, tumor proliferation, skin erythema, and metastasis. These results establish IBC-derived CCL2 as a key factor driving macrophage expansion, and indirectly tumor growth, with transcriptomic analysis demonstrating the activation of multiple inflammatory pathways. Finally, primary human IBCs exhibit macrophage infiltration and an enriched macrophage RNA signature. Thus, this human IBC model provides insight into the distinctive biology of IBC, and highlights potential therapeutic approaches to this deadly disease.

Robust inflammatory breast cancer gene signature using nonparametric random forest analysis.

Inflammatory breast cancer (IBC) is a rare, aggressive cancer found in all the molecular breast cancer subtypes. Despite extensive previous efforts to screen for transcriptional differences between IBC and non-IBC patients, a robust IBC-specific molecular signature has been elusive. We report a novel IBC-specific gene signature (59 genes; G59) that achieves 100% accuracy in discovery and validation samples (45/45 correct classification) and remarkably only misclassified one sample (60/61 correct classification) in an independent dataset. G59 is independent of ER/HER2 status, molecular subtypes and is specific to untreated IBC samples, with most of the genes being enriched for plasma membrane cellular component proteins, interleukin (IL), and chemokine signaling pathways. Our finding suggests the existence of an IBC-specific molecular signature, paving the way for the identification and validation of targetable genomic drivers of IBC.

Lipocalin 2 promotes inflammatory breast cancer tumorigenesis and skin invasion.

Inflammatory breast cancer (IBC) is an aggressive form of primary breast cancer characterized by rapid onset and high risk of metastasis and poor clinical outcomes. The biological basis for the aggressiveness of IBC is still not well understood and no IBC-specific targeted therapies exist. In this study, we report that lipocalin 2 (LCN2), a small secreted glycoprotein belonging to the lipocalin superfamily, is expressed at significantly higher levels in IBC vs non-IBC tumors, independently of molecular subtype. LCN2 levels were also significantly higher in IBC cell lines and in their culture media than in non-IBC cell lines. High expression was associated with poor-prognosis features and shorter overall survival in IBC patients. Depletion of LCN2 in IBC cell lines reduced colony formation, migration, and cancer stem cell populations in vitro and inhibited tumor growth, skin invasion, and brain metastasis in mouse models of IBC. Analysis of our proteomics data showed reduced expression of proteins involved in cell cycle and DNA repair in LCN2-silenced IBC cells. Our findings support that LCN2 promotes IBC tumor aggressiveness and offer a new potential therapeutic target for IBC.

Targeting Lipocalin-2 in Inflammatory Breast Cancer Cells with Small Interference RNA and Small Molecule Inhibitors.

Inflammatory Breast Cancer (IBC) is an aggressive form of invasive breast cancer, highly metastatic, representing 2-4% of all breast cancer cases in the United States. Despite its rare nature, IBC is responsible for 7-10% of all breast cancer deaths, with a 5-year survival rate of 40%. Thus, targeted and effective therapies against IBC are needed. Here, we proposed Lipocalin-2 (LCN2)-a secreted glycoprotein aberrantly abundant in different cancers-as a plausible target for IBC. In immunoblotting, we observed higher LCN2 protein levels in IBC cells than non-IBC cells, where the LCN2 levels were almost undetectable. We assessed the biological effects of targeting LCN2 in IBC cells with small interference RNAs (siRNAs) and small molecule inhibitors. siRNA-mediated LCN2 silencing in IBC cells significantly reduced cell proliferation, viability, migration, and invasion. Furthermore, LCN2 silencing promoted apoptosis and arrested the cell cycle progression in the G0/G1 to S phase transition. We used in silico analysis with a library of 25,000 compounds to identify potential LCN2 inhibitors, and four out of sixteen selected compounds significantly decreased cell proliferation, cell viability, and the AKT phosphorylation levels in SUM149 cells. Moreover, ectopically expressing LCN2 MCF7 cells, treated with two potential LCN2 inhibitors (ZINC00784494 and ZINC00640089) showed a significant decrease in cell proliferation. Our findings suggest LCN2 as a promising target for IBC treatment using siRNA and small molecule inhibitors.

Genetic Variants and Tumor Immune Microenvironment: Clues for Targeted Therapies in Inflammatory Breast Cancer (IBC).

To better understand the etiology of inflammatory breast cancer (IBC) and identify potential therapies, we studied genomic alterations in IBC patients. Targeted, next-generation sequencing (NGS) was performed on cell-free DNA (cfDNA) (n = 33) and paired DNA from tumor tissues (n = 29) from 32 IBC patients. We confirmed complementarity between cfDNA and tumor tissue genetic profiles. We found a high incidence of germline variants in IBC patients that could be associated with an increased risk of developing the disease. Furthermore, 31% of IBC patients showed deficiencies in the homologous recombination repair (HRR) pathway (BRCA1, BRCA2, PALB2, RAD51C, ATM, BARD1) making them sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors. We also characterized the tumor-infiltrating lymphocytes (TILs) in tumor tissue biopsies by studying several markers (CD4, CD8, FoxP3, CD20, PD-1, and PD-L1) through immunohistochemistry (IHC) staining. In 7 of 24 (29%) patients, tumor biopsies were positive for PD-L1 and PD-1 expression on TILs, making them sensitive to PD-1/PD-L1 blocking therapies. Our results provide a rationale for considering PARP inhibitors and PD-1/PDL1 blocking immunotherapy in qualifying IBC patients.

A novel CD74-ROS1 gene fusion in a patient with inflammatory breast cancer: a case report.

BACKGROUND: CD74-ROS1 fusion genes have been detected in non-small cell lung carcinomas (NSCLC), but not in inflammatory breast cancer. CASE PRESENTATION: Herein, we report a CD74-ROS1 fusion gene identified in a 64-year-old Chinese woman with inflammatory breast cancer (IBC). The patient initially presented with a rapidly growing mass in the left breast with diffuse erythema developing over a period of 2 months. Diagnosis of invasive breast carcinoma was made by core needle biopsy. Positron emission tomography-computed tomography (PET/CT) demonstrated multiple organ metastases. Genomic DNA was extracted from tumor tissue and analyzed using next-generation sequencing (NGS). The CD74-ROS1 fusion gene was detected in the genomic DNA. The patient refused crizotinib treatment, and could not tolerate the side effects of palliative chemotherapy. Unfortunately, the patient died 4 months after diagnosis. CONCLUSION: We report the case of a CD74-ROS1 fusion gene in a patient with IBC. This may reveal, for the first time, a possible association between CD74-ROS1 gene fusion and rapid progression of inflammatory breast cancer. Multigene panel testing can be performed when rapidly progressive breast cancer occurs and could reveal potential therapeutic strategies.

New Treatment Strategies for the Inflammatory Breast Cancer.

OPINION STATEMENT: Inflammatory breast cancer (IBC) remains the most aggressive type of breast cancer. During the past decade, enormous progress has been made to refine diagnostic criteria and establish multimodality treatment strategies as keys for the improvement of survival outcomes. Multiple genomic studies enabled a better understanding of underlying tumor biology, which is responsible for the complex and aggressive nature of IBC. Despite these important achievements, outcomes for this subgroup of patients remain unsatisfactory compared to locally advanced non-IBC counterparts. Global efforts are now focused on identifying novel strategies that will improve treatment response, prolong survival for metastatic patients, achieve superior local control, and possibly increase the cure rate for locally advanced disease. Genomic technologies constitute the most important tool that will support future clinical progress. Gene-expressing profiling of the tumor tissue and liquid biopsy are important parts of the everyday clinical practice aiming to guide treatment decisions by providing information on tumor molecular drivers or primary and acquired resistance to treatment. The International IBC expert panel and IBC International Consortium made a tremendous effort to define IBC as a distinct entity of BC, and they will continue to lead and support the research for this rare and very aggressive disease. Finally, a uniform platform is now required to develop and lead large, multi-arm, proof-of-concept clinical trials that perform rapid, focused, and cost-effective evaluations of potential novel therapeutics in IBC.

Whole-genome sequencing of phenotypically distinct inflammatory breast cancers reveals similar genomic alterations to non-inflammatory breast cancers.

BACKGROUND: Inflammatory breast cancer (IBC) has a highly invasive and metastatic phenotype. However, little is known about its genetic drivers. To address this, we report the largest cohort of whole-genome sequencing (WGS) of IBC cases. METHODS: We performed WGS of 20 IBC samples and paired normal blood DNA to identify genomic alterations. For comparison, we used 23 matched non-IBC samples from the Cancer Genome Atlas Program (TCGA). We also validated our findings using WGS data from the International Cancer Genome Consortium (ICGC) and the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We examined a wide selection of genomic features to search for differences between IBC and conventional breast cancer. These include (i) somatic and germline single-nucleotide variants (SNVs), in both coding and non-coding regions; (ii) the mutational signature and the clonal architecture derived from these SNVs; (iii) copy number and structural variants (CNVs and SVs); and (iv) non-human sequence in the tumors (i.e., exogenous sequences of bacterial origin). RESULTS: Overall, IBC has similar genomic characteristics to non-IBC, including specific alterations, overall mutational load and signature, and tumor heterogeneity. In particular, we observed similar mutation frequencies between IBC and non-IBC, for each gene and most cancer-related pathways. Moreover, we found no exogenous sequences of infectious agents specific to IBC samples. Even though we could not find any strongly statistically distinguishing genomic features between the two groups, we did find some suggestive differences in IBC: (i) The MAST2 gene was more frequently mutated (20% IBC vs. 0% non-IBC). (ii) The TGF ß pathway was more frequently disrupted by germline SNVs (50% vs. 13%). (iii) Different copy number profiles were observed in several genomic regions harboring cancer genes. (iv) Complex SVs were more frequent. (v) The clonal architecture was simpler, suggesting more homogenous tumor-evolutionary lineages. CONCLUSIONS: Whole-genome sequencing of IBC manifests a similar genomic architecture to non-IBC. We found no unique genomic alterations shared in just IBCs; however, subtle genomic differences were observed including germline alterations in TGFß pathway genes and somatic mutations in the MAST2 kinase that could represent potential therapeutic targets.

Wnt (canonical and non canonical) pathways in breast carcinoma with extensive vascular invasion and inflammatory breast carcinoma.

BACKGROUND: Breast carcinoma with extensive peritumoral vascular invasion (ePVI-BC) is a cancer with massive vascular invasion (>10) detected in more than one slide. This neoplasm shows clinic-pathological affinity with inflammatory breast carcinoma (IBC). In this paper we evaluate their biological relationship through the study of surrogate markers (ß-catenin and NFAT5) of Canonical (cWnt) and non-canonical (nWnt) Wnt pathways activation. METHODS: By immunoistochemistry, we investigate ß-catenin and NFAT5 in 39 IBC, 74 ePVI-BC and 84 control cases (CG-BC). RESULTS: cWnt was activated in 100 % of ePVI-BC, in 64 % of IBC and 10 % of CG-BC. nWnt was activated in 20 % of ePVI-BC, 50 % of IBC and 1% of CG-BC. The prognosis of carcinomas with nWnt activated was poor similar to IBC. The statistical analysis evidences as both the pathways are synergistic in malignant progression and survival time. ß-catenin show an important association with prognostic factors and NFAT5 shows a relevant prognostic role on OS (p = 1.5*10-6) and DFS (P = 1,2*10-4). nWnt is associated with a worse prognosis independently of cWnt. cWnt is associated with adverse prognosis (DFS p = 0.0469; OS p = 0.004891) but its prognostic role is indifferent in carcinoma with nWnt activated. CONCLUSIONS: Canonical Wnt pathway is involved in malignant progression with dominant role for vascular invasion whereas non canonical Wnt pathway plays an important role on survival time including the capacity to identify carcinomas with IBC-like prognosis. Furthermore ePVI may represent a "prodromal form of IBC" as demonstrated by its clinicopathological and biological similarity with IBC.