Protein profiling of fine-needle aspirates reveals subtype-associated immune signatures and involvement of chemokines in breast cancer

Minimally invasive biopsy-based diagnostics in support of precision cancer medicine

Precision cancer medicine (PCM) to support the treatment of solid tumors requires minimally invasive diagnostics. Here, we describe the development of fine-needle aspiration biopsy-based (FNA) molecular cytology which will be increasingly important in diagnostics and adaptive treatment. We provide support for FNA-based molecular cytology having a significant potential to replace core needle biopsy (CNB) as a patient-friendly potent technique for tumor sampling for various tumor types. This is not only because CNB is a more traumatic procedure and may be associated with more complications compared to FNA-based sampling, but also due to the recently developed molecular methods used with FNA. Recent studies show that image-guided FNA in combination with ultrasensitive molecular methods also offers opportunities for characterization of the tumor microenvironment which can aid therapeutic decisions. Here we provide arguments for an increased implementation of molecular FNA-based sampling as a patient-friendly diagnostic method, which may, due to its repeatability, facilitate regular sampling that is needed during different treatment lines, to provide tumor information, supporting treatment decisions, shortening lead times in healthcare, and benefit healthcare economics.

The elusive Luminal B breast cancer and the mysterious chemokines

PURPOSE

Invasive ductal breast cancer (IDC) is heterogeneous. Staging and immunohistochemistry (IH) allow for effective therapy but are not yet ideal. Women with Luminal B tumors show an erratic response to treatment. This prospective study with 81 women with breast cancer aims to improve the prognostic stratification of Luminal B patients.

METHODS

This is a prospective translational study with 81 women with infiltrating ductal carcinoma, grouped by TNM staging and immunohistochemistry, for survival analysis, and their correlations with the chemokines. Serum measurements of 13 chemokines were performed, including 7 CC chemokines [CCL2(MCP1), CCL3(MIP1α), CCL4(MIP1β), CCL5(Rantes), CCL11(Eotaxin), CCL17(TARC), CCL20(MIP3α)], 6 CXC chemokines [CXCL1(GroAlpha), CXCL5(ENA78), CCXCL8(IL-8), CXCL9(MIG), CXCL10(IP10), CXCL11(ITAC)].

RESULTS

Overall survival was significantly dependent on tumor staging and subtypes by immunohistochemistry, with a median follow-up time the 32.87 months (3.67-65.63 months). There were age correlations with IP10/CXCL10 chemokines (r =  0.4360; p = 0.0079) and TARC/CCL17 (Spearman + 0.2648; p = 0.0360). An inverse correlation was found between body weight and the chemokines Rantes/CCL5 (r = - 0.3098; p = 0.0169) and Eotaxin/CCL11 (r = - 0.2575; p = 0.0470). Smokers had a higher concentration of MIP3α/CCL20 (Spearman + 0.3344; p = 0.0267). Luminal B subtype patients who expressed lower concentrations of ENA78/CXCL5 (≤ 254.83 pg/ml) (Log-Rank p = 0.016) and higher expression of MIP1β/CCL4 (> 34.84 pg/ml) (Log-Rank p = 0.014) had a higher risk of metastases.

CONCLUSION

Patients with Luminal B breast tumors can be better stratified by serum chemokine expression, suggesting that prognosis is dependent on biomarkers other than TNM and IH.

Multiplex protein analysis and ensemble machine learning methods of fine needle aspirates from prostate cancer patients reveal potential diagnostic signatures associated with tumour grade

BACKGROUND

Improved molecular diagnosis is needed in prostate cancer (PC). Fine needle aspiration (FNA) is a minimally invasive biopsy technique, less traumatic compared to core needle biopsy, and could be useful for diagnosis of PC. Molecular biomarkers (BMs) in FNA-samples can be assessed for prediction, eg of immunotherapy efficacy before treatment as well as at treatment decision time points during disease progression.

METHODS

In the present pilot study, the expression levels of 151 BM proteins were analysed by proximity extension assay in FNA-samples from 16 patients, including benign prostate lesions (n = 3) and cancers (n = 13). An ensemble data analysis strategy was applied using several machine learning models.

RESULTS

Twelve potentially predictive BM proteins correlating with International Society of Urological Pathology grade groups were identified, among them vimentin, tissue factor pathway inhibitor 2, and integrin beta-5. The validity of the results was supported by network analysis that showed functional associations between most of the identified putative BMs. We also showed that multiple immune checkpoint targets can be assessed (eg PD-L1, CD137, and Galectin-9), which may support the selection of immunotherapy in advanced PC. Results are promising but need further validation in a larger cohort.

CONCLUSIONS

Our pilot study represents a "proof of concept" and shows that multiplex profiling of potential diagnostic and predictive BM proteins is feasible on tumour material obtained by FNA sampling of prostate cancer. Moreover, our results demonstrate that an ensemble data analysis strategy may facilitate the identification of BM signatures in pilot studies when the patient cohort is limited.

Serum immuno-oncology markers carry independent prognostic information in patients with newly diagnosed metastatic breast cancer, from a prospective observational study

BACKGROUND

Metastatic breast cancer (MBC) is a challenging disease, and despite new therapies, prognosis is still poor for a majority of patients. There is a clinical need for improved prognostication where immuno-oncology markers can provide important information. The aim of this study was to evaluate serum immuno-oncology markers in MBC patients and their respective relevance for prediction of survival.

PATIENTS AND METHODS

We investigated a broad panel of 92 immuno-oncology proteins in serum from 136 MBC patients included in a prospective observational study (NCT01322893) with long-term follow-up. Serum samples were collected before start of systemic therapy and analyzed using multiplex proximity extension assay (Olink Target 96 Immuno-Oncology panel). Multiple machine learning techniques were used to identify serum markers with highest importance for prediction of overall and progression-free survival (OS and PFS), and associations to survival were further evaluated using Cox regression analyses. False discovery rate was then used to adjust for multiple comparisons.

RESULTS

Using random forest and random survival forest analyses, we identified the top nine and ten variables of highest predictive importance for OS and PFS, respectively. Cox regression analyses revealed significant associations (P < 0.005) of higher serum levels of IL-8, IL-10 and CAIX with worse OS in multivariable analyses, adjusted for established clinical prognostic factors including circulating tumor cells (CTCs). Similarly, high serum levels of IL-8, IL-10, ADA and CASP8 significantly associated with worse PFS. Interestingly, high serum levels of FasL significantly associated with improved OS and PFS. In addition, CSF-1, IL-6, MUC16, TFNSFR4 and CD244 showed suggestive evidence (P < 0.05) for an association to survival in multivariable analyses. After correction for multiple comparisons, IL-8 still showed strong evidence for correlation to survival.

CONCLUSION

To conclude, we found six serum immuno-oncology markers that were significantly associated with OS and/or PFS in MBC patients, independently of other established prognostic factors including CTCs. Furthermore, an additional five serum immuno-oncology markers provided suggestive evidence for an independent association to survival. These findings highlight the relevance of immuno-oncology serum markers in MBC patients and support their usefulness for improved prognostication. Trial registration Clinical Trials (NCT01322893), registered March 25, 2011.

Longitudinal liver sampling in patients with chronic hepatitis B starting antiviral therapy reveals hepatotoxic CD8+ T cells

Accumulation of activated immune cells results in nonspecific hepatocyte killing in chronic hepatitis B (CHB), leading to fibrosis and cirrhosis. This study aims to understand the underlying mechanisms in humans and to define whether these are driven by widespread activation or a subpopulation of immune cells. We enrolled CHB patients with active liver damage to receive antiviral therapy and performed longitudinal liver sampling using fine-needle aspiration to investigate mechanisms of CHB pathogenesis in the human liver. Single-cell sequencing of total liver cells revealed a distinct liver-resident, polyclonal CD8+ T cell population that was enriched at baseline and displayed a highly activated immune signature during liver damage. Cytokine combinations, identified by in silico prediction of ligand-receptor interaction, induced the activated phenotype in healthy liver CD8+ T cells, resulting in nonspecific Fas ligand-mediated killing of target cells. These results define a CD8+ T cell population in the human liver that can drive pathogenesis and a key pathway involved in their function in CHB patients.

CCL13 and human diseases

CCL13/MCP-4 belongs to the CC chemokine family, which induces chemotaxis in many immune cells. Despite extensive research into its function in numerous disorders, a thorough analysis of CCL13 is not yet accessible. The role of CCL13 in human disorders and existing CCL13-focused therapies are outlined in this study. The function of CCL13 in rheumatic diseases, skin conditions, and cancer is comparatively well-established, and some studies also suggest that it may be involved in ocular disorders, orthopedic conditions, nasal polyps, and obesity. We also give an overview of research that found very little evidence of CCL13 in HIV, nephritis, and multiple sclerosis. Even though CCL13-mediated inflammation is frequently linked to disease pathogenesis, it's fascinating to note that in some conditions, like primary biliary cholangitis (PBC) and suicide, it might even act as a preventative measure.

Prognostic biomarker MCP-4 triggers epithelial-mesenchymal transition via the p38 MAPK pathway in ovarian cancer

BACKGROUND

Monocyte chemoattractant protein-4 (MCP-4/CCL13) is a proinflammatory factor that is overexpressed in various malignant tumors and may play an important role in tumor progression and metastasis. However, its role and mechanism of action in ovarian cancer remains unknown.

METHODS

Immunohistochemistry (IHC) was performed to detect the expression of MCP-4 in ovarian cancer tissues, and the effect of MCP-4 on patient survival and prognosis was analyzed. Overexpression and suppression of MCP-4 in ovarian cancer cell lines were then established, and their effects on cell invasion, migration, and apoptosis were studied. ES-2 cell lines were employed to establish a peritoneal dissemination model in nude mice. Western blotting was performed to detect the expression of epithelial mesenchymal transition (EMT) markers and the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway.

RESULTS

MCP-4 was highly expressed in ovarian cancer tissues and its expression level was related to the prognosis of patients with ovarian cancer. MCP-4 overexpression promoted the migration and invasion of ovarian cancer cells but inhibited apoptosis. MCP-4 overexpression increased the expression of MMP-2, MMP-9, N-cadherin, vimentin and Bcl2/Bax and decreased the expression of E-cadherin. MCP-4 overexpression increased the phosphorylation of the p38 MAPK pathway. The inhibition of MCP-4 expression indicated an opposite trend. In vivo experiments have also confirmed that MCP-4 overexpression can promote metastasis of ovarian cancer.

CONCLUSION

MCP-4 promotes ovarian cancer progression through the p38 MAPK signaling pathway, and may be a potential biomarker and therapeutic target for ovarian cancer.

A comprehensive review of chemokine CXC17 (VCC1) in cancer, infection, and inflammation

A crucial component of the immune system are chemokiness. Chemokine's dysregulation has been linked to a number of pathological diseases. Recently, CXCL17, a chemokine belonging to the CXC subfamily, was identified. With regard to a number of physiological conditions and disorders, CXCL17 either has homeostatic or pathogenic effects. Some research suggests that CXCL17 is an orphan ligand, despite the fact that G protein-coupled receptor (GPR) 35 has been suggested as a possible receptor for CXCL17. Since CXCL17 is primarily secreted by mucosal epithelia, such as those in the digestive and respiratory tracts, under physiological circumstances, this chemokine is referred to as a mucosal chemokine. Macrophages and monocytes are the cells that express GPR35 and hence react to CXCL17. In homeostatic conditions, this chemokine has anti-inflammatory, antibacterial, and chemotactic properties. CXCL17 promotes angiogenesis, metastasis, and cell proliferation in pathologic circumstances like malignancies. However, other studies suggest that CXCL17 may have anti-tumor properties. Additionally, studies have shown that CXCL17 may have a role in conditions such as idiopathic pulmonary fibrosis, multiple sclerosis, asthma, and systemic sclerosis. Additionally, deregulation of CXCL17 in some diseases may serve as a biomarker for diagnosis and prognosis. Clarifying the underlying mechanism of CXCL17's activity in homeostatic and pathological situations may thus increase our understanding of its role and hold promise for the development of novel treatment strategies.

Role of chemokines in breast cancer

Chemokines belong to a family of chemoattractant cytokines and are well known to have an essential role in various cancer aetiologies. Multiplesubsets of immune cells are recruited and enrolled into the tumor microenvironment through interactions between chemokines and their specific receptors. These populations and their interactions have a distinct impact on tumor growth, progression, and treatment outcomes. While it is clear that many chemokines and their cognate receptors can be detected in breast and other cancers, the role of each chemokine and receptor has yet to be determined. This review focuses on the main chemokines that play a crucial role in the tumor microenvironment, emphasizing breast cancer. We have also discussed the techniques used to identify the chemokines and their future implication in the early diagnosis of cancer. In-depth knowledge of chemokines and their role in breast cancer progression can provide specific targets for breast cancer biotherapy.

Correlation of CCL8 expression with immune cell infiltration of skin cutaneous melanoma: potential as a prognostic indicator and therapeutic pathway

BACKGROUND

The tumor microenvironment (TME) is critical in the progression and metastasis of skin cutaneous melanoma (SKCM). Differences in tumor-infiltrating immune cells (TICs) and their gene expression have been linked to cancer prognosis. Given that immunotherapy can be effective against SKCM, we aimed to identify key genes that regulate the immunological state of the TME in SKCM.

METHODS

Data from 471 SKCM patients in the The Cancer Genome Atlas were analyzed using ESTIMATE algorithms to generate an ImmuneScore, StromalScore, and EstimateScore for each patient. Patients were classified into low- or high-score groups based on median values, then compared in order to identify differentially expressed genes (DEGs). Then a protein-protein interaction (PPI) network was developed, and a prognostic model was created using uni- and multivariate Cox regression as well as the least absolute shrinkage and selection operator (LASSO). Key DEGs were identified using the web-based tool GEPIA. Profiles of TIC subpopulations in each patient were analyzed using CIBORSORT, and possible correlations between key DEG expression and TICs were explored. Levels of CCL8 were determined in SKCM and normal skin tissue using immunohistochemistry.

RESULTS

Two scores correlated positively with the prognosis of SKCM patients. Comparison of the low- and high-score groups revealed 1684 up-regulated and 18 down-regulated DEGs, all of which were enriched in immune-related functions. The prognostic model identified CCL8 as a key gene, which CIBERSORT found to correlate with M1 macrophages. Immunohistochemistry revealed strong expression in SKCM tissue, but failed to detect the protein in normal skin tissue.

CONCLUSIONS

CCL8 is a potential prognostic marker for SKCM, and it may become an effective target for melanoma in which M1 macrophages play an important role.

Bioinformatics identification of CCL8/21 as potential prognostic biomarkers in breast cancer microenvironment

BACKGROUND

Breast cancer (BC) is the most common malignancy among females worldwide. The tumor microenvironment usually prevents effective lymphocyte activation and infiltration, and suppresses infiltrating effector cells, leading to a failure of the host to reject the tumor. CC chemokines play a significant role in inflammation and infection.

METHODS

In our study, we analyzed the expression and survival data of CC chemokines in patients with BC using several bioinformatics analyses tools.

RESULTS

The mRNA expression of CCL2/3/4/5/7/8/11/17/19/20/22 was remarkably increased while CCL14/21/23/28 was significantly down-regulated in BC tissues compared with normal tissues. Methylation could down-regulate expression of CCL2/5/15/17/19/20/22/23/24/25/26/27 in BC. Low expression of CCL3/4/23 was found to be associated with drug resistance in BC. Results from Kaplan-Meier plotter and BC Gene-Expression Miner v4.2 (bcGenExMiner) v4.2 demonstrated that BC patients with high CCL8 and low CCL19/21/22 expression were more likely to have a worse prognosis. CCL8 expression was significantly up-regulated in BC tissues compared with normal tissues. High CCL8 expression was significantly correlated with negative PR, negative ER, positive nodal status, triple-negative BC subtype, basal-like BC subtype, triple-negative and basal-like BC subtype and high grades. CCL21 was down-regulated in BC, while high levels of CCL21 was associated with negative PR, triple-negative subtype, basal-like subtype and low tumor grade. Functional analysis demonstrated that CCL8 and CCL21 were involved in carcinogenesis, tumor immune escape and chemoresistance in BC.

CONCLUSION

Integrative bioinformatics analysis demonstrated CCL8/21 as potential prognostic biomarkers in BC microenvironment.

Multiplex immune protein profiling of fine-needle aspirates from patients with non-small-cell lung cancer reveals signatures associated with PD-L1 expression and tumor stage

Biomarker signatures identified through minimally invasive procedures already at diagnosis of non‐small‐cell lung cancer (NSCLC) could help to guide treatment with immune checkpoint inhibitors (ICI). Here, we performed multiplex profiling of immune‐related proteins in fine‐needle aspirate (FNA) samples of thoracic lesions from patients with NSCLC to assess PD‐L1 expression and identify related protein signatures. Transthoracic FNA samples from 14 patients were subjected to multiplex antibody‐based profiling by proximity extension assay (PEA). PEA profiling employed protein panels relevant to immune and tumor signaling and was followed by Qlucore^® Omics Explorer analysis. All lesions analyzed were NSCLC adenocarcinomas, and PEA profiles could be used to monitor 163 proteins in all but one sample. Multiple key immune signaling components (including CD73, granzyme A, and chemokines CCL3 and CCL23) were identified and expression of several of these proteins (e.g., CCL3 and CCL23) correlated to PD‐L1 expression. We also found EphA2, a marker previously linked to inferior NSCLC prognosis, to correlate to PD‐L1 expression. Our identified protein signatures related to stage included, among others, CXCL10 and IL12RB1. We conclude that transthoracic FNA allows for extensive immune and tumor protein profiling with assessment of putative biomarkers of important for ICI treatment selection in NSCLC.

Expression of cornulin in tongue squamous cell carcinoma

The aim of the study is to identify cornulin (CRNN) protein expression associated with advancement of tongue squamous cell carcinoma (TSCC). A comparison of addictive (containing potential carcinogens) versus non-addiction causative agents was expected to allow detection of differences in CRNN expression associated with TSCC. Bespoke tissue microarrays (TMAs) were prepared and immunohistochemistry (IHC) performed to determine the changes in CRNN expression in epithelial cells of node-negative (pN-), node-positive (pN+) TSCC and non-cancer patients’ oral tissues. TMAs were validated by performing IHC on whole diagnostic tissues. Chi-square test or Fisher’s-exact tests were used to establish significant expression differences. Analogous analyses were performed for biomarkers previously associated with TSCC, namely collagen I alpha 2 (COL1A2) and decorin (DCN) to compare the significance of CRNN. Keratinisation and its level (low, extensive) were studied in relation to CRNN so that the extent of squamous differentiation could better be assessed.

IHC immunoreactive score (IRS) clustered the patients based on weak/moderate (Low (IRS ≤ +3)) or strong (High (IRS ≥ +4)) expression groups. A low expression was observed in a larger number of patients in control proteins COL1A2 (77.3%), DCN (87.5%) and target protein CRNN (52.3%), respectively. Low CRNN expression was observed in TSCC where nodes were involved (pN+: mean 1.4 ± 2.1) (p = 0.248). Keratinisation (%) was low (0% ≤ 50%) in 42.2% and extensive (1% ≥ 50.0%) in 57.8% patients. In conclusion, our study suggested that Low CRNN expression was associated with grade and lymph node metastasis in TSCC. CRNN expression is independent of addiction, however potentially carcinogenic addictive substances might be aiding in the disease progression.

The Importance of Breast Adipose Tissue in Breast Cancer

Adipose tissue is a complex endocrine organ, with a role in obesity and cancer. Adipose tissue is generally linked to excessive body fat, and it is well known that the female breast is rich in adipose tissue. Hence, one can wonder: what is the role of adipose tissue in the breast and why is it required? Adipose tissue as an organ consists of adipocytes, an extracellular matrix (ECM) and immune cells, with a significant role in the dynamics of breast changes throughout the life span of a female breast from puberty, pregnancy, lactation and involution. In this review, we will discuss the importance of breast adipose tissue in breast development and its involvement in breast changes happening during pregnancy, lactation and involution. We will focus on understanding the biology of breast adipose tissue, with an overview on its involvement in the various steps of breast cancer development and progression. The interaction between the breast adipose tissue surrounding cancer cells and vice-versa modifies the tumor microenvironment in favor of cancer. Understanding this mutual interaction and the role of breast adipose tissue in the tumor microenvironment could potentially raise the possibility of overcoming breast adipose tissue mediated resistance to therapies and finding novel candidates to target breast cancer.

Chemokines in bone-metastatic breast cancer: Therapeutic opportunities

Due to non-response to chemotherapy, incomplete surgical resection, and resistance to checkpoint inhibitors, breast cancer with bone metastasis is notoriously difficult to cure. Therefore, the development of novel, efficient strategies to tackle bone metastasis of breast cancer is urgently needed. Chemokines, which induce directed migration of immune cells and act as guide molecules between diverse cells and tissues, are small proteins indispensable in immunity. These complex chemokine networks play pro-tumor roles or anti-tumor roles when produced by breast cancer cells in the tumor microenvironment. Additionally, chemokines have diverse roles when secreted by various immune cells in the tumor microenvironment of breast cancer, which can be roughly divided into immunosuppressive effects and immunostimulatory effects. Recently, targeting chemokine networks has been shown to have potential for use in treatment of metastatic malignancies, including bone-metastatic breast cancer. In this review, we focus on the role of chemokines networks in the biology of breast cancer and metastasis to the bone. We also discuss the therapeutic opportunities and future prospects of targeting chemokine networks, in combination with other current standard therapies, for the treatment of bone-metastatic breast cancer.

Immune related proteins and tumor infiltrating CD8+ lymphocytes in hypopharyngeal cancer in relation to human papillomavirus (HPV) and clinical outcome

BACKGROUND

Hypopharyngeal cancer (HPSCC) shows a poor clinical outcome, while HPSCC, caused by human papillomavirus (HPV), presents a better outcome. Here, HPCC, immune proteins, and tumor infiltrating CD8+ lymphocytes (CD8+ TILs) were evaluated in relation to HPV and outcome.

METHODS

Fresh frozen tissue from four HPV-positive HPSCC, 39 HPV-negative HPSCC, and normal samples were analyzed for protein expression by the Proseek immuno-oncology immunoassay. CD8+ TIL numbers evaluated by immunohistochemistry on 144 formalin-fixed biopsies were analyzed in relation to clinical outcome.

RESULTS

Proteins differing between HPV-positive and negative HPSCC included CD8A, PD-L1, Fas ligand, and chemokines. High CD8+ TIL numbers were correlated to improve clinical outcome in HPV-negative HPSCC.

CONCLUSIONS

High expression of immune proteins in HPV-positive HPSCC may explain the better clinical outcome. CD8+ TILs are of relevance for outcome of HPV-negative HPSCC, while tumors with high immune activity but poor patient survival suggest a role for immune therapy.

Apoptotic caspases inhibit abscopal responses to radiation and identify a new prognostic biomarker for breast cancer patients

Caspase 3 (CASP3) has a key role in the execution of apoptosis, and many cancer cells are believed to disable CASP3 as a mechanism of resistance to cytotoxic therapeutics. Alongside, CASP3 regulates stress-responsive immunomodulatory pathways, including secretion of type I interferon (IFN). Here, we report that mouse mammary carcinoma TSA cells lacking Casp3 or subjected to chemical caspase inhibition were as sensitive to the cytostatic and cytotoxic effects of radiation therapy (RT) in vitro as their control counterparts, yet secreted increased levels of type I IFN. This effect originated from the accrued accumulation of irradiated cells with cytosolic DNA, likely reflecting the delayed breakdown of cells experiencing mitochondrial permeabilization in the absence of CASP3. Casp3^-/- TSA cells growing in immunocompetent syngeneic mice were more sensitive to RT than their CASP3-proficient counterparts, and superior at generating bona fide abscopal responses in the presence of an immune checkpoint blocker. Finally, multiple genetic signatures of apoptotic proficiency were unexpectedly found to have robust negative (rather than positive) prognostic significance in a public cohort of breast cancer patients. However, these latter findings were not consistent with genetic signatures of defective type I IFN signaling, which were rather associated with improved prognosis. Differential gene expression analysis on patient subgroups with divergent prognosis (as stratified by independent signatures of apoptotic proficiency) identified SLC7A2 as a new biomarker with independent prognostic value in breast cancer patients. With the caveats associated with the retrospective investigation of heterogeneous, public databases, our data suggest that apoptotic caspases may influence the survival of breast cancer patients (or at least some subsets thereof) via mechanisms not necessarily related to type I IFN signaling as they identify a novel independent prognostic biomarker that awaits prospective validation.

Weighted gene correlation network analysis identifies RSAD2, HERC5, and CCL8 as prognostic candidates for breast cancer

As the most commonly diagnosed malignant tumor in female population, the prognosis of breast cancer is affected by complex gene interaction networks. In this research weighted gene co-expression network analysis (WGCNA) would be utilized to build a gene co-expression network to identify potential biomarkers for prediction the prognosis of patients with breast cancer. We downloaded GSE25065 from Gene Expression Omnibus database as the test set. GSE25055 and GSE42568 were utilized to validate findings in the research. Seven modules were established in the GSE25065 by utilizing average link hierarchical clustering. Three hub genes, RSAD2, HERC5, and CCL8 were screened out from the significant module (R ²  = 0.44), which were considerably interrelated to worse prognosis. Within test dataset GSE25065, RSAD2, and CCL8 were correlated with tumor stage, grade, and lymph node metastases, whereas HERC5 was correlated with lymph node metastases and tumor grade. In the validation dataset GSE25055 and RSAD2 expression was correlated with tumor grade, stage, and size, whereas HERC5 was related to tumor stage and tumor grade, and CCL8 was associated with tumor size and tumor grade. Multivariable survival analysis demonstrated that RSAD2, HERC5, and CCL8 were independent risk factors. In conclusion, the WGCNA analysis conducted in this study screened out novel prognostic biomarkers of breast cancer. Meanwhile, further in vivo and in vitro studies are required to make the clear molecular mechanisms.

CXCL17-derived CD11b+Gr-1+ myeloid-derived suppressor cells contribute to lung metastasis of breast cancer through platelet-derived growth factor-BB

Background

Metastasis is the major cause of death from breast cancer. Colonization and adaption of metastatic cells in distant organs is a rate-limiting step of the cancer spreading. The underlying mechanisms responsible for the colonization of breast cancer to lung metastatic niches are not fully understood.

Methods

Specific gene contributions to lung metastasis were identified by comparing gene profiles of 4T1 tumors metastasizing to various organs via microarray. The oncogenic properties CXCL17 were examined by in vivo spontaneous metastasis mouse model. The chemotactic activity of CXCL17 on CD11b⁺Gr-1⁺ myeloid-derived suppressor cells (MDSCs) was examined by both in vitro and in vivo models. The therapeutic effects of MDSC depletion and platelet-derived growth factor-BB (PDGF-BB) inhibition were examined by orthotic models.

Results

Here, we demonstrate that breast cancer cells secrete CXCL17, which increases the accumulation of CD11b⁺Gr-1⁺ MDSCs in the lungs. Metastatic lung-infiltrating CD11b⁺Gr-1⁺ MDSCs induce angiogenesis in the lungs and facilitate cancer extravasation and survival that ultimately promote lung metastases. CXCL17 increases CD11b⁺Gr-1⁺ MDSCs to express PDGF-BB, which not only contributes to CD11b⁺Gr-1⁺ MDSC-mediated angiogenesis in the lung metastatic niche, but is also involved in the colonization of breast cancer. Consequently, both CD11b⁺Gr-1⁺ MDSC depletion and PDGF receptor inhibitor effectively prevents CXCL17-driven lung metastasis in breast cancer. More importantly, patients with high levels of CXCL17 have shorter distant metastasis-free and overall survival rates, indicators of poor prognosis.

Conclusion

Our study reveals that MDSCs derived by CXCL17 contribute to the establishment of a lung metastatic niche by PDGF-BB secretion and provide a rationale for development of CXCL17 or PDGF-BB antagonists to inhibit or prevent lung metastasis in cases of breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1114-3) contains supplementary material, which is available to authorized users.