Breast cancer metastasis: immune profiling of lymph nodes reveals exhaustion of effector T cells and immunosuppression

Intra-patient spatial comparison of non-metastatic and metastatic lymph nodes reveals a reduction in CD169+ macrophages within metastatic breast cancers

BACKGROUND

Breast cancer cells suppress the host immune system to efficiently invade the lymph nodes; however, the underlying mechanism remains incompletely understood. Here, we aimed to comprehensively characterise the effects of breast cancers on immune cells in the lymph nodes.

METHODS

We collected non-metastatic and metastatic lymph node samples from 6 patients with breast cancer with lymph node metastasis. We performed bulk transcriptomics, spatial transcriptomics, and imaging mass cytometry to analyse the obtained lymph nodes. Furthermore, we conducted histological analyses against a larger patient cohort (474 slices from 58 patients).

FINDINGS

The comparison between paired lymph nodes with and without metastasis from the same patients demonstrated that the number of CD169+ lymph node sinus macrophages, an initiator of anti-cancer immunity, was reduced in metastatic lymph nodes (36.7 ± 21.1 vs 7.3 ± 7.0 cells/mm2, p = 0.0087), whereas the numbers of other major immune cell types were unaltered. We also detected that the infiltration of CD169+ macrophages into metastasised cancer tissues differed by section location within tumours, suggesting that CD169+ macrophages were gradually decreased after anti-cancer reactions. Furthermore, CD169+ macrophage elimination was prevalent in major breast cancer subtypes and correlated with breast cancer staging (p = 0.022).

INTERPRETATION

We concluded that lymph nodes with breast cancer metastases have fewer CD169+ macrophages, which may be detrimental to the activity of anti-cancer immunity.

FUNDING

JSPS KAKENHI (16H06279, 20H03451, 20H04842, 22H04925, 19K16770, and 21K15530, 24K02236), JSPS Fellows (JP22KJ1822), AMED (JP21ck0106698), JST FOREST (JPMJFR2062), Caravel, Co., Ltd, Japan Foundation for Applied Enzymology, and Sumitomo Pharma Co., Ltd. under SKIPS.

Identification of the novel exhausted T cell CD8 + markers in breast cancer

Cancer is one of the most concerning public health issues and breast cancer is one of the most common cancers in the world. The immune cells within the tumor microenvironment regulate cancer development. In this study, single immune cell data sets were used to identify marker gene sets for exhausted CD8 + T cells (CD8Tex) in breast cancer. Machine learning methods were used to cluster subtypes and establish the prognostic models with breast cancer bulk data using the gene sets to evaluate the impacts of CD8Tex. We analyzed breast cancer overexpressing and survival-associated marker genes and identified CD8Tex hub genes in the protein-protein-interaction network. The relevance of the hub genes for CD8 + T-cells in breast cancer was evaluated. The clinical associations of the hub genes were analyzed using bulk sequencing data and spatial sequencing data. The pan-cancer expression, survival, and immune association of the hub genes were analyzed. We identified biomarker gene sets for CD8Tex in breast cancer. CD8Tex-based subtyping systems and prognostic models performed well in the separation of patients with different immune relevance and survival. CRTAM, CLEC2D, and KLRB1 were identified as CD8Tex hub genes and were demonstrated to have potential clinical relevance and immune therapy impact. This study provides a unique view of the critical CD8Tex hub genes for cancer immune therapy.

Two Different Immune Profiles Are Identified in Sentinel Lymph Nodes of Early-Stage Breast Cancer

In the management of early-stage breast cancer (BC), lymph nodes (LNs) are typically characterised using the One-Step Nucleic Acid Amplification (OSNA) assay, a standard procedure for assessing subclinical metastasis in sentinel LNs (SLNs). The pivotal role of LNs in coordinating the immune response against BC is often overlooked. Our aim was to improve prognostic information provided by the OSNA assay and explore immune-related gene signatures in SLNs. The expression of an immune gene panel was analysed in SLNs from 32 patients with Luminal A early-stage BC (cT1-T2 N0). Using an unsupervised approach based on these expression values, this study identified two clusters, regardless of the SLN invasion: one evidencing an adaptive anti-tumoral immune response, characterised by an increase in naive B cells, follicular T helper cells, and activated NK cells; and another with a more undifferentiated response, with an increase in the activated-to-resting dendritic cells (DCs) ratio. Through a protein-protein interaction (PPI) network, we identified seven immunoregulatory hub genes: CD80, CD40, TNF, FCGR3A, CD163, FCGR3B, and CCR2. This study shows that, in Luminal A early-stage BC, SLNs gene expression studies enable the identification of distinct immune profiles that may influence prognosis stratification and highlight key genes that could serve as potential targets for immunotherapy.

Evaluation of markers of immunity in different metastatic immune microenvironments suggests more suppression within breast to liver metastases in breast cancer

PURPOSE

Programmed death receptor ligand-1 (PD-L1) expression and tumor mutational burden (TMB) are approved screening biomarkers for immune checkpoint inhibition (ICI) in advanced triple negative breast cancer. We examined these biomarkers along with characterization of the tumor microenvironment (TME) between breast tumors (BrTs), axillary metastases (AxMs), liver metastases (LvMs), non-axillary lymph node metastases, and non-liver metastases to determine differences related to site of metastatic disease.

METHODS

3076 unpaired biopsies from breast cancer patients were analyzed using whole transcriptome sequencing and NextGen DNA depicting TMB within tumor sites. The PD-L1 positivity was determined with VENTANA PD-L1 (SP142) assay. The immune cell fraction within the TME was calculated by QuantiSeq and MCP-counter.

RESULTS

Compared to BrT, more LvM samples had a high TMB (≥ 10 mutations/Mb) and fewer LvM samples had PD-L1+ expression. Evaluation of the TME revealed that LvM sites harbored lower infiltration of adaptive immune cells, such as CD4+, CD8+, and regulatory T-cells compared with the BrT foci. We saw differences in innate immune cell infiltration in LvM compared to BrT, including neutrophils and NK cells.

CONCLUSIONS

LvMs are less likely to express PD-L1+ tumor cells but more likely to harbor high TMB as compared to BrTs. Unlike AxMs, LvMs represent a more immunosuppressed TME and demonstrate lower gene expression associated with adaptive immunity compared to BrTs. These findings suggest biopsy site be considered when interpreting results that influence ICI use for treatment and further investigation of immune composition and biomarkers expression by metastatic site.

The Tumor Immune Microenvironment in Breast Cancer Progression

BACKGROUND

The tumor microenvironment significantly influences breast cancer development, progression, and metastasis. Various immune cell populations, including T cells, B cells, NK cells, and myeloid cells exhibit diverse functions in different breast cancer subtypes, contributing to both anti-tumor and pro-tumor activities.

PURPOSE

This review provides an overview of the predominant immune cell populations in breast cancer subtypes, elucidating their suppressive and prognostic effects. We aim to outline the role of the immune microenvironment from normal breast tissue to invasive cancer and distant metastasis.

METHODS

A comprehensive literature review was conducted to analyze the involvement of immune cells throughout breast cancer progression.

RESULTS

In breast cancer, tumors exhibit increased immune cell infiltration compared to normal tissue. Variations exist across subtypes, with higher levels observed in triple-negative and HER2+ tumors are linked to better survival. In contrast,  ER+ tumors display lower immune infiltration, associated with poorer outcomes. Furthermore, metastatic sites commonly exhibit a more immunosuppressive microenvironment.

CONCLUSION

Understanding the complex interaction between tumor and immune cells during breast cancer progression is essential for future research and the development of immune-based strategies. This comprehensive understanding may pave the way for more effective treatment approaches and improved patients outcomes.

Investigating the role of tumour-to-skin proximity in predicting nodal metastasis in breast cancer

BACKGROUND

Understanding the factors influencing nodal status in breast cancer is vital for axillary staging, therapy, and patient survival. The nodal stage remains a crucial factor in prognostication indices. This study investigates the relationship between tumour-to-skin distance (in T1-T3 tumours where the skin is not clinically involved) and the risk of nodal metastasis.

METHODS

We retrospectively reviewed data from 100 patients who underwent neoadjuvant chemotherapy (NACT). Besides patient demographics and tumour variables, a radiologist retrospectively reviewed pre-operative MRI to measure tumour-to-skin distance. R core packages were used for univariate (χ2 and T-Wilcoxon tests) and bivariate logistic regression statistical analysis.

RESULTS

Of 95 analysable datasets, patients' median age was 51 years (IQR: 42-61), 97% were symptomatic (rest screen detected), and the median tumour size was 43 mm (IQR, 26-52). On multivariate analysis, increasing invasive tumour size (p = 0.02), ER positivity (p = 0.007) and shorter tumour-to-skin distance (p = 0.05) correlated with nodal metastasis.  HER2 was not included in multivariate analysis as there was no association with nodal status on univariate analysis. In node-positive tumours, as tumour size increased, the tumour-to-skin distance decreased (r = - 0.34, p = 0.026). In node-negative tumours, there was no correlation (r = + 0.18, p = 0.23).

CONCLUSION

This study shows that non-locally advanced cancers closer to the skin (and consequent proximity to subdermal lymphatics) are associated with a greater risk of nodal metastasis. Pre-operative identification of those more likely to be node positive may suggest the need for a second-look USS since a higher nodal stage may lead to a change in therapeutic strategies, such as upfront systemic therapy, node marking, and axillary clearance without the need to return to theatre following sentinel node biopsy.

Single cell deciphering of progression trajectories of the tumor ecosystem in head and neck cancer

Head and neck squamous cell carcinoma is the sixth most common cancer worldwide and has high heterogeneity and unsatisfactory outcomes. To better characterize the tumor progression trajectory, we perform single-cell RNA sequencing of normal tissue, precancerous tissue, early-stage, advanced-stage cancer tissue, lymph node, and recurrent tumors tissue samples. We identify the transcriptional development trajectory of malignant epithelial cells and a tumorigenic epithelial subcluster regulated by TFDP1. Furthermore, we find that the infiltration of POSTN+ fibroblasts and SPP1+ macrophages gradually increases with tumor progression; their interaction or interaction with malignant cells also gradually increase to shape the desmoplastic microenvironment and reprogram malignant cells to promote tumor progression. Additionally, we demonstrate that during lymph node metastasis, exhausted CD8+ T cells with high CXCL13 expression strongly interact with tumor cells to acquire more aggressive phenotypes of extranodal expansion. Finally, we delineate the distinct features of malignant epithelial cells in primary and recurrent tumors, providing a theoretical foundation for the precise selection of targeted therapy for tumors at different stages. In summary, the current study offers a comprehensive landscape and deep insight into epithelial and microenvironmental reprogramming throughout initiation, progression, lymph node metastasis and recurrence of head and neck squamous cell carcinoma.

The CUL5 E3 ligase complex negatively regulates central signaling pathways in CD8+ T cells

CD8+ T cells play an important role in anti-tumor immunity. Better understanding of their regulation could advance cancer immunotherapies. Here we identify, via stepwise CRISPR-based screening, that CUL5 is a negative regulator of the core signaling pathways of CD8+ T cells. Knocking out CUL5 in mouse CD8+ T cells significantly improves their tumor growth inhibiting ability, with significant proteomic alterations that broadly enhance TCR and cytokine signaling and their effector functions. Chemical inhibition of neddylation required by CUL5 activation, also enhances CD8 effector activities with CUL5 validated as a major target. Mechanistically, CUL5, which is upregulated by TCR stimulation, interacts with the SOCS-box-containing protein PCMTD2 and inhibits TCR and IL2 signaling. Additionally, CTLA4 is markedly upregulated by CUL5 knockout, and its inactivation further enhances the anti-tumor effect of CUL5 KO. These results together reveal a negative regulatory mechanism for CD8+ T cells and have strong translational implications in cancer immunotherapy.

Anti-cathepsin D immunotherapy triggers both innate and adaptive anti-tumour immunity in breast cancer

BACKGROUND AND PURPOSE

Triple-negative breast cancer (TNBC) has poorer outcomes than other breast cancers (BC), including HER2+ BC. Cathepsin D (CathD) is a poor prognosis marker overproduced by BC cells, hypersecreted in the tumour microenvironment with tumour-promoting activity. Here, we characterized the immunomodulatory activity of the anti-CathD antibody F1 and its improved Fab-aglycosylated version (F1M1) in immunocompetent mouse models of TNBC (C57BL/6 mice harbouring E0771 cell grafts) and HER2-amplified BC (BALB/c mice harbouring TUBO cell grafts).

EXPERIMENTAL APPROACH

CathD expression was evaluated by western blotting and immunofluorescence, and antibody binding to CathD by ELISA. Antibody anti-tumour efficacy was investigated in mouse models. Immune cell recruitment and activation were assessed by immunohistochemistry, immunophenotyping, and RT-qPCR.

KEY RESULTS

F1 and F1M1 antibodies remodelled the tumour immune landscape. Both antibodies promoted innate antitumour immunity by preventing the recruitment of immunosuppressive M2-polarized tumour-associated macrophages (TAMs) and by activating natural killer cells in the tumour microenvironment of both models. This translated into a reduction of T-cell exhaustion markers in the tumour microenvironment that could be locally supported by enhanced activation of anti-tumour antigen-presenting cell (M1-polarized TAMs and cDC1 cells) functions. Both antibodies inhibited tumour growth in the highly-immunogenic E0771 model, but only marginally in the immune-excluded TUBO model, indicating that anti-CathD immunotherapy is more relevant for BC with a high immune cell infiltrate, as often observed in TNBC.

CONCLUSION AND IMPLICATION

Anti-CathD antibody-based therapy triggers the anti-tumour innate and adaptive immunity in preclinical models of BC and is a promising immunotherapy for immunogenic TNBC.

Lymph node metastasis and tumor-educated immune tolerance: Potential therapeutic targets against distant metastasis

Lymph node metastasis has been shown to positively associated with the prognosis of many cancers. However, in clinical treatment, lymphadenectomy is not always successful, suggesting that immune cells in the tumor and sentinel lymph nodes still play a pivotal role in tumor immunosuppression. Recent studies had shown that tumors can tolerate immune cells through multiple strategies, including tumor-induced macrophage reprogramming, T cells inactivation, production of B cells pathogenic antibodies and activation of regulatory T cells to promote tumor colonization, growth, and metastasis in lymph nodes. We reviewed the bidirectional effect of immune cells on anti-tumor or promotion of cancer cell metastasis during lymph node metastasis, and the mechanisms by which malignant cancer cells modify immune cells to create a more favorable environment for the growth and survival of cancer cells. Research and treatment strategies focusing on the immune system in lymph nodes and potential immune targets in lymph node metastasis were also be discussed.

Molecular Imaging of Innate Immunity and Immunotherapy

The innate immune system plays a key role as the first line of defense in various human diseases including cancer, cardiovascular and inflammatory diseases. In contrast to tissue biopsies and blood biopsies, in vivo imaging of the innate immune system can provide whole body measurements of immune cell location and function and changes in response to disease progression and therapy. Rationally developed molecular imaging strategies can be used in evaluating the status and spatio-temporal distributions of the innate immune cells in near real-time, mapping the biodistribution of novel innate immunotherapies, monitoring their efficacy and potential toxicities, and eventually for stratifying patients that are likely to benefit from these immunotherapies. In this review, we will highlight the current state-of-the-art in noninvasive imaging techniques for preclinical imaging of the innate immune system particularly focusing on cell trafficking, biodistribution, as well as pharmacokinetics and dynamics of promising immunotherapies in cancer and other diseases; discuss the unmet needs and current challenges in integrating imaging modalities and immunology and suggest potential solutions to overcome these barriers.

One Step Nucleic Acid Amplification (OSNA) Lysate Samples Are Suitable to Establish a Transcriptional Metastatic Signature in Patients with Early Stage Hormone Receptors-Positive Breast Cancer

The One Step Nucleic Acid Amplification (OSNA) is being adopted worldwide for sentinel lymph nodes (SLNs) staging in breast cancer (BC). As major disadvantage, OSNA precludes prognostic information based on structural evaluation of SLNs. Our aim is to identify biomarkers related to tumor-microenvironment interplay exploring gene expression data from the OSNA remaining lysate. This study included 32 patients with early stage hormone receptors-positive BC. Remaining OSNA lysates were prepared for targeted RNA-sequencing analysis. Identification of differentially expressed genes (DEGs) was performed by DESeq2 in R and data analysis in STATA. The results show that, in metastatic SLNs, several genes were upregulated: KRT7, VTCN1, CD44, GATA3, ALOX15B, RORC, NECTIN2, LRG1, CD276, FOXM1 and IGF1R. Hierarchical clustering analysis revealed three different clusters. The identified DEGs codify proteins mainly involved in cancer aggressiveness and with impact in immune response. The overexpression of the immune suppressive genes VTCN1 and CD276 may explain that no direct evidence of activation of immune response in metastatic SLNs was found. We show that OSNA results may be improved incorporating microenvironment-related biomarkers that may be useful in the future for prognosis stratification and immunotherapy selection. As OSNA assay is being implemented for SLNs staging in other cancers, this approach could also have a wider utility.

Molecular proof for Lophomonas infection in a patient with history of breast cancer

We report a 52-year-old patient with a history of breast cancer (BC) referred to the clinic of Afzalipour Hospital, in Kerman, eastern Iran, with a 1-week complaint of restless dyspnea. A chest computed tomography scan revealed consolidations in the upper lobes of both lungs. The patient had no history of smoking or underlying diseases that would predispose her to consolidation, including pneumonia. Then, bronchoscopy was performed for the patient, and bronchoalveolar lavage fluid was sent to the Iranian National Registry Center, where the Lophomonas parasite was detected in the sample and confirmed using a polymerase chain reaction test. Finally, her symptoms improved by receiving oral metronidazole three times a day for 3 weeks.

Leveraging the Dynamic Immune Environment Triad in Patients with Breast Cancer: Tumour, Lymph Node, and Peripheral Blood

During the anti-tumour response to breast cancer, the primary tumour, the peripheral blood, and the lymph nodes each play unique roles. Immunological features at each site reveal evidence of continuous immune cross-talk between them before, during and after treatment. As such, immune responses to breast cancer are found to be highly dynamic and truly systemic, integrating three distinct immune sites, complex cell-migration highways, as well as the temporal dimension of disease progression and treatment. In this review, we provide a connective summary of the dynamic immune environment triad of breast cancer. It is critical that future studies seek to establish dynamic immune profiles, constituting multiple sites, that capture the systemic immune response to breast cancer and define patient-selection parameters resulting in more significant overall responses and survival rates for breast cancer patients.

Identification of a Prognostic Transcriptome Signature for Hepatocellular Carcinoma with Lymph Node Metastasis

Hepatocellular carcinoma (HCC) is one of the most aggressive malignant tumors, and the prognosis of HCC patients with lymph node metastasis (LNM) is poor. However, robust biomarkers for predicting the prognosis of HCC LNM are still lacking. This study used weighted gene coexpression network analysis of GSE28248 (N = 80) microarray data to identify gene modules associated with HCC LNM and validated in GSE40367 dataset (N = 18). The prognosis-related genes in the HCC LNM module were further screened based on the prognostic curves of 371 HCC samples from TCGA. We finally developed a prognostic signature, PSG-30, as a prognostic-related biomarker in HCC LNM. The HCC subtypes identified by PSG-30-based consensus clustering analysis showed significant differences in prognosis, clinicopathological stage, m6A modification, ferroptosis activation, and immune characteristics. In addition, RAD54B was selected by regression model as an independent risk factor affecting the prognosis of HCC patients with LNM, and its expression was significantly positively correlated with tumor mutational burden and microsatellite instability in high-risk subtypes. Patients with high RAD54B expression had a better prognosis in the immune checkpoint inhibitor-treated cohorts but had a poor prognosis in the HCC sorafenib-treated group. The association of high RAD54B expression with LNM in breast cancer (BRCA) and cholangiocarcinoma and its prognostic effect in BRCA LNM cases suggest the value of RAD54B at the pancancer level. In conclusion, PSG-30 can effectively identify HCC LNM population with poor prognosis, and high-risk patients with high RAD54B expression may be more suitable for immunotherapy.

Characteristics of Prognostic Programmed Cell Death-Related Long Noncoding RNAs Associated With Immune Infiltration and Therapeutic Responses to Colon Cancer

Programmed cell death (PCD) plays an important role in the onset and progression of various cancers. The molecular events surrounding the occurrence of abnormally expressed long noncoding RNAs (lncRNAs) leading to colon cancer (CC) have become a focus. We comprehensively evaluated the roles of PCD-related lncRNAs in the clinical management of CC and their immune responses. Therefore, we screened 41 prognostic PCD-related lncRNAs in The Cancer Genome Atlas database using co-expression analysis and assigned patients to groups according to the results of cluster analysis. The immune response and functions of cluster 2 were substantially suppressed, which might explain the poor prognosis in this group. A prognostic model comprising eight PCD-related lncRNAs was developed, and its effectiveness was verified using an external database. High-and low-risk groups had different epigenetic modifications and changes in immune cell infiltration. Patients in the high-risk group were resistant to immunotherapy and various chemotherapeutic drugs. Studies in vitro and in vivo further confirmed a carcinogenic role of the lncRNA U62317.4. Our findings of the prognostic value of PCD-related lncRNAs revealed their important roles in immune response disorders, thus providing valuable insights into the clinical management and molecular mechanisms of CC.

Distinct Gene Expression Profiles of Matched Primary and Metastatic Triple-Negative Breast Cancers

Background: Although triple-negative breast cancer (TNBC) is associated with an increased risk of recurrence and metastasis, the molecular mechanisms underlying metastasis in TNBC remain unknown. To identify transcriptional changes and genes regulating metastatic progression in TNBC, we compared the transcriptomic profiles of primary and matched metastatic tumors using massively parallel RNA sequencing. Methods: We performed gene expression profiling using formalin-fixed paraffin-embedded (FFPE) TNBC tissues of patients from two cohorts: the Zurich cohort (n = 31) and the Stavanger cohort (n = 5). Among the 31 patients in the Zurich cohort, 18 had primary TNBC tumors that did not metastasize, and 13 had primary tumors that metastasized (11 paired primary and locoregional recurrences). The Stavanger cohort included five matched primary and metastatic TNBC tumors. Significantly differentially expressed genes (DEGs; absolute fold change ≥2, p < 0.05) were identified and subjected to functional analyses. We investigated if there was any overlap between DEGs from both the cohorts with epithelial-to-mesenchymal-to-amoeboid transition (EMAT) gene signature. xCell was used to estimate relative fractions of 64 immune and stromal cell types in each RNA-seq sample. Results: In the Zurich cohort, we identified 1624 DEGs between primary TNBC tumors and matched metastatic lesions. xCell analysis revealed a significantly higher immune scores for metastatic lesions compared to paired primary tumors in the Zurich cohort. We also found significant upregulation of three MammaPrint signature genes (HRASLS, TGFB3 and RASSF7) in primary tumors that metastasized compared to primary tumors that remained metastasis-free. In the Stavanger cohort, we identified 818 DEGs between primary tumors and matched metastatic lesions. No significant differences in xCell immune scores were observed. We found that 21 and 14 DEGs from Zurich and Stavanger cohort, respectively, overlapped with the EMAT gene signature. In both cohorts, genes belonging to the MMP, FGF, and PDGFR families were upregulated in primary tumors compared to matched metastatic lesions. Conclusions: Our results suggest that distinct gene expression patterns exist between primary TNBCs and matched metastatic tumors. Further studies are warranted to explore whether these discrete expression profiles underlie or result from disease status.

Cytokines: Can Cancer Get the Message?

Simple Summary

Cytokines are important molecular players in cancer development, progression, and potential targets for treatment. Despite being small and overlooked, research has revealed that cytokines influence cancer biology in multiple ways. Cytokines are often found to contribute to immune function, cell damage, inflammation, angiogenesis, metastasis, and several other cellular processes important to tumor survival. Cytokines have also proven to have powerful effects on complex tumor microenvironment molecular biology and microbiology. Due to their heavy involvement in critical cancer-related processes, cytokines have also become attractive therapeutic targets for cancer treatment. In this review, we describe the relationship between several cytokines and crucial cancer-promoting processes and their therapeutic potential.

Abstract

Cytokines are small molecular messengers that have profound effects on cancer development. Increasing evidence shows that cytokines are heavily involved in regulating both pro- and antitumor activities, such as immune activation and suppression, inflammation, cell damage, angiogenesis, cancer stem-cell-like cell maintenance, invasion, and metastasis. Cytokines are often required to drive these cancer-related processes and, therefore, represent an important research area for understanding cancer development and the potential identification of novel therapeutic targets. Interestingly, some cytokines are reported to be related to both pro- and anti-tumorigenicity, indicating that cytokines may play several complex roles relating to cancer pathogenesis. In this review, we discuss some major cancer-related processes and their relationship with several cytokines.

XGBoost-based and tumor-immune characterized gene signature for the prediction of metastatic status in breast cancer

Background

For a long time, breast cancer has been a leading cancer diagnosed in women worldwide, and approximately 90% of cancer-related deaths are caused by metastasis. For this reason, finding new biomarkers related to metastasis is an urgent task to predict the metastatic status of breast cancer and provide new therapeutic targets.

Methods

In this research, an efficient model of eXtreme Gradient Boosting (XGBoost) optimized by a grid search algorithm is established to realize auxiliary identification of metastatic breast tumors based on gene expression. Estimated by ten-fold cross-validation, the optimized XGBoost classifier can achieve an overall higher mean AUC of 0.82 compared to other classifiers such as DT, SVM, KNN, LR, and RF.

Results

A novel 6-gene signature (SQSTM1, GDF9, LINC01125, PTGS2, GVINP1, and TMEM64) was selected by feature importance ranking and a series of in vitro experiments were conducted to verify the potential role of each biomarker. In general, the effects of SQSTM in tumor cells are assigned as a risk factor, while the effects of the other 5 genes (GDF9, LINC01125, PTGS2, GVINP1, and TMEM64) in immune cells are assigned as protective factors.

Conclusions

Our findings will allow for a more accurate prediction of the metastatic status of breast cancer and will benefit the mining of breast cancer metastasis-related biomarkers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03369-9.