Neutrophil in the suppressed immune microenvironment: Critical prognostic factor for lung adenocarcinoma patients with KEAP1 mutation.

Purpose: It is still unclear whether KEAP1 mutation is detrimental to immunotherapy of lung adenocarcinoma (LUAD) patients, we try to analyse the exact changes in the TME in LUAD patients with KEAP1 mutations and to identify key factors influencing prognosis. Experimental design: A total of 1,029 patients with lung squamous carcinoma (LUSC) or LUAD with data obtained from The Cancer Genome Atlas were included in this study. The TME and OS of patients with LUAD stratified by mutant versus wild-type KEAP1 status were comprehensively measured. Moreover, we classified LUAD patients with KEAP1 mutations into three subtypes, by unsupervised consensus clustering. We further analysed the TME, OS, commutated genes and metabolic pathways of different subgroups. A total of 40 LUAD patients underwent immunotherapy were collected and classified into mutant KEAP1 group and wild-type KEAP1 group. We also conducted immunohistochemical staining in KEAP1-MT groups. Result: Suppressed TME was observed not only in LUAD patients but also in LUSC patients. LUAD patients with mutant KEAP1 underwent immunotherapy had worse PFS than wild-type KEAP1. Unsupervised consensus clustering analysis suggested that the three subtypes of patients exhibited different densities of neutrophil infiltration and had different OS results: cluster 2 patients had significantly higher levels of neutrophils had significantly worse prognoses than those of patients in clusters 1 and 3 and patients with wild-type KEAP1. Univariate and multivariate Cox analyses proved that a high density of neutrophils was significantly associated with worse OS and immunohistochemical staining proved that shorter PFS showed high density of neutrophils. Conclusion: KEAP1 mutation significantly suppresses the tumour immune microenvironment in LUAD patients. LUAD patients with mutant KEAP1 underwent immunotherapy had worse PFS than with wild-type KEAP1. Neutrophils may play an important role in the prognosis of LUAD patients with KEAP1 mutations and may provide a promising therapeutic target.

Trends in cancer-related suicide in the United States: a population-based epidemiology study spanning 40 years of data.

Large cohort studies examining trends in cancer-related suicide are lacking. We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database, encompassing a total of 4,870,410 patients diagnosed with cancer from 1975 to 2017 in the United States. Joinpoint regression was used to estimate the annual percent change (APC) and average annual percentage change (AAPC) of age-adjusted rates of suicide. In the past 40 years, we revealed a gradual increase in cancer-related suicide rates from 1975 to 1989, followed by a gradual decrease from 1989 to 2013, and a marked decrease from 2013 to 2017. These trends suggested the potential impact of advancements in psychosocial care for patients with cancer in contributing to the observed decrease in suicide rates.

PD-1/PD-L1 Inhibitor - Related Adverse Events and Their Management in Breast Cancer.

As the positive results of multiple clinical trials were released, the Programmed cell death 1 (PD-1) and Programmed cell death ligand 1 (PD-L1) inhibitors emerge as the focus of integrative breast cancer treatment. PD-1/PD-L1 inhibitors are often used as a sequential agent to be combined with other agents such as chemotherapeutic agents, targeted agents, and radiation therapy. As multiple therapies are administered simultaneously or in sequence, they are prone to a variety of adverse effects on patients while achieving efficacy. It is a challenge for clinicians to maintaining the balance between immune-related adverse effects(irAEs) and treatment efficacy. Previous literatures have paid lots of attention on the adverse effects caused by immunosuppressive agents themselves, while there is a dearth of the research on the management of adverse immune effects during the combination of immunotherapy with other treatments. In this review, we discuss the overall incidence of irAEs caused by PD-1/PD-L1 inhibitors in combination with various types of treatments in breast cancer, including chemotherapy, CTLA-4 inhibitors, targeted therapy, and radiotherapy, and systematically summarizes the clinical management to each organ-related adverse immune reaction. It is important to emphasize that in the event of irAEs such as neurological, hematologic, and cardiac toxicity, there is no alternative treatment but to terminate immunotherapy. Thus, seeking more effective strategy of irAEs' management is imminent and clinicians are urged to raise the awareness of the management of adverse immune reactions.

Risk of cerebrovascular disease after cancer diagnosis in the United States.

The risk of subsequent cerebrovascular disease among cancer patients of multiple cancers in the US is not well understood. A total of 3,843,261 cancer patients diagnosed from 1975 to 2018, were included from the surveillance, epidemiology, and end results (SEER) database. Standardized mortality ratios (SMRs) and absolute excess risks (AERs) were estimated. The overall cerebrovascular disease SMR was 1.04 (95% CI, 1.03-1.04), and the AER per 10,000 person-years at risk was 0.89. When compared with the US general population, greater cerebrovascular disease risk was correlated with certain cancer sites, American Indian/Alaska Native race, Asian or Pacific Islander race, unmarried marital status, distant metastasis, younger age, and an earlier time of cancer diagnosis. Clinically, more precision and proactive strategies for cerebrovascular disease prevention are required to subgroup of cancer patients with a greater risk of cerebrovascular disease, especially within the first two months.

AGR2: a secreted protein worthy of attention in diagnosis and treatment of breast cancer.

AGR2 is a secreted protein widely existing in breast. In precancerous lesions, primary tumors and metastatic tumors, the expression of AGR2 is increased, which has aroused our interest. This review introduces the gene and protein structure of AGR2. Its endoplasmic reticulum retention sequence, protein disulfide isomerase active site and multiple protein binding sequences endow AGR2 with diverse functions inside and outside breast cancer cells. This review also enumerates the role of AGR2 in the progress and prognosis of breast cancer, and emphasizes that AGR2 can be a promising biomarker and a target for immunotherapy of breast cancer, providing new ideas for early diagnosis and treatment of breast cancer.

A Systematic Study on Zinc-Related Metabolism in Breast Cancer.

Breast cancer has become the most common cancer worldwide. Despite the major advances made in the past few decades in the treatment of breast cancer using a combination of chemotherapy, endocrine therapy, and immunotherapy, the genesis, treatment, recurrence, and metastasis of this disease continue to pose significant difficulties. New treatment approaches are therefore urgently required. Zinc is an important trace element that is involved in regulating various enzymatic, metabolic, and cellular processes in the human body. Several studies have shown that abnormal zinc homeostasis can lead to the onset and progression of various diseases, including breast cancer. This review highlights the role played by zinc transporters in pathogenesis, apoptosis, signal transduction, and potential clinical applications in breast cancer. Additionally, the translation of the clinical applications of zinc and associated molecules in breast cancer, as well as the recent developments in the zinc-related drug targets for breast cancer treatment, is discussed. These developments offer novel insights into understanding the concepts and approaches that could be used for the diagnosis and management of breast cancer.

Large pneumothorax following thoracic and lumbar tumor surgery: Risk factors and management strategies.

Objective: Large pneumothorax is a rare but dangerous complication following thoracic and lumbar tumor surgery. There is little discussion about the features of large pneumothorax following spinal tumor surgery. The purpose of this study was to analyze the characteristics of postoperative pneumothorax, identify factors related to large pneumothorax, and propose a management algorithm for prevention, diagnosis, and treatment. Methods: Included in this retrospective study were 118 patients who developed pneumothorax after receiving thoracic and lumbar tumor surgery between January 2015 and October 2021. A measurement of lung compression ≥20% on chest CT or x-ray was defined as large pneumothorax, and potential risk factors for large pneumothorax were identified by univariate analysis. Results: Spinal tumor history and intraoperative blood loss were risk factors for large pneumothorax. The common symptoms of postoperative pneumothorax were chest pain, chest tightness and dyspnea. The mean longest transverse diameter of tumors was 6.63 ± 2.4 cm. En bloc resection was performed in 70 patients, with a mean operation time of 6.9 ± 2.5 h and mean intraoperative blood loss of 1771 ± 1387 ml. The most common pathologies were chondrosarcoma, giant cell tumors of bone, and neurogenic tumors. Conclusion: During surgery, an artificial dura mater patch and a prolene suture can be used to repair the pleural and lung defects. We recommend chest CT as the preferred method for identifying postoperative pneumothorax. If a patient presents severe dyspnea, a large pneumothorax or concurrent pleural effusion, application of chest drainage is strongly recommended.

Incidence, risk factors, prevention and treatment of postmastectomy pain syndrome in breast cancer: A multicenter study.

BACKGROUND: Postmastectomy pain syndrome (PMPS) is a common postoperative condition after breast cancer surgery. PURPOSE: The aim of this study was to investigate the incidence rate and risk factors of PMPS, and to propose prevention and treatment methods. METHODS: The study included 1790 postoperative breast cancer patients from three hospitals from 2017 to 2021, of which 302 (13.0%) patients with PMPS were included in the study. RESULTS: Age, breast surgery type, axillary surgery type and radiotherapy are the risk factors of PMPS. Age, radiotherapy and chemotherapy affect the pain degree of PMPS during movement. CONCLUSIONS: For breast cancer patients with high risk factors, pain should be actively prevented during perioperative period. Oral pharmacological agents, multidisciplinary combination therapy, local anesthetics and regional anesthesia are the most common treatment of PMPS.

PD-1/PD-L1 Inhibitor-Associated Myocarditis: Epidemiology, Characteristics, Diagnosis, Treatment, and Potential Mechanism.

Immune checkpoint inhibitors (ICIs) induce T-cell activation against cancer cells, and due to their anti-tumor function in multiple cancers, ICIs have been considered an important option for oncotherapy. PD-1/PD-L1 inhibitors are now widely used as ICIs for many types of cancers in clinical practices. Myocarditis induced by anti-PD-1/PD-L1 agents is uncommon but shows potentially fatal toxicity. In this review, we attempted to conclude the incidence, characteristics, diagnosis, and treatments, as well as illustrate the potential pathogenesis from the perspectives of T-lymphocyte infiltration, disturbance of regulatory T cells, cytokines, macrophage-mediated inflammatory response, and synergistic effect of PD-1/PD-L1 and CTLA4.

PD-1/PD-L1 Inhibitors in Patients With Preexisting Autoimmune Diseases.

Autoimmune diseases and malignant tumors are the two hotspots and difficulties that are currently being studied and concerned by the medical field. The use of PD-1/PD-L1 inhibitors improves the prognosis of advanced tumors, but excessive immune responses can also induce immune-related adverse events (irAEs). Due to this concern, many clinical trials exclude cancer patients with preexisting autoimmune disease (AID). This review outlines the possible mechanisms of irAE, discusses the safety and efficacy of PD-1/PD-L1 inhibitors in cancer patients with preexisting AID, and emphasizes the importance of early recognition, continuous monitoring, and multidisciplinary cooperation in the prevention and management of cancer patients with preexisting AID.

Butyrate emerges as a crucial effector of Zhi-Zi-Chi decoctions to ameliorate depression via multiple pathways of brain-gut axis.

Gut microbiota has emerged as a crucial target of gut-brain axis to influence depression. Zhi-Zi-Chi decoctions (ZZCD), as a classic oral formula in clinic, is widely applied in depression treatment nowadays. However, the underlying mechanism in the antidepressant activity of ZZCD remains unknown. A classic depression model of chronic mild unpredictable stress (CUMS) was established in rats based on the results of behavioral tests and hippocampal histomorphology. 16S rRNA sequencing analysis indicated that ZZCD could increase short-chain fatty acid-producing and anti-inflammatory bacteria and reduce inflammatory and tryptophan-metabolizing bacteria. Furthermore, ZZCD reversed the alterations of BDNF, TNF-α, pro-inflammatory cytokines and neurotransmitters in the gut, blood and brain along the brain-gut axis and restored the decrease of butyrate in cecal content caused by CUMS. Then, butyrate was utilized to validate its ameliorative effect on pathological characteristics of depressive rats. Taken together, these results show that ZZCD exhibits antidepressant effect through modulating gut microbiota to facilitate the production of butyrate, which further regulate anti-inflammation, neurotransmitters, endocrine and BDNF along the gut-brain axis. Hence, this study fills the gap of the antidepressive mechanism of ZZCD in the light of the brain-gut axis and established a multi-targets and multi-levels platform eventually for further research into the mechanism of other TCM efficacy.

Recent advances of transcriptomics and proteomics in triple-negative breast cancer prognosis assessment.

Triple-negative breast cancer (TNBC), a heterogeneous tumour that lacks the expression of oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), is often characterized by aggressiveness and tends to recur or metastasize. TNBC lacks therapeutic targets compared with other subtypes and is not sensitive to endocrine therapy or targeted therapy except chemotherapy. Therefore, identifying the prognostic characteristics and valid therapeutic targets of TNBC could facilitate early personalized treatment. Due to the rapid development of various technologies, researchers are increasingly focusing on integrating 'big data' and biological systems, which is referred to as 'omics', as a means of resolving it. Transcriptomics and proteomics analyses play an essential role in exploring prospective biomarkers and potential therapeutic targets for triple-negative breast cancers, which provides a powerful engine for TNBC's therapeutic discovery when combined with complementary information. Here, we review the recent progress of TNBC research in transcriptomics and proteomics to identify possible therapeutic goals and improve the survival of patients with triple-negative breast cancer. Also, researchers may benefit from this article to catalyse further analysis and investigation to decipher the global picture of TNBC cancer.

Subsequent risk of suicide among 9,300,812 cancer survivors in US: A population-based cohort study covering 40 years of data.

BACKGROUND: Large cohort studies that estimate the variation in suicide risk among cancer patients, depending on disease type and patient characteristics, are lacking. We aimed to investigate suicide risk among patients with different cancers types in the United States (US) and to identify subsets of patients at particularly high risk. METHODS: A total of 9,300,812 cases of cancer in the Surveillance, Epidemiology, and End Results (SEER) database that were diagnosed between 1975 and 2016 were included in the study. Standardized mortality ratio (SMR) and absolute excess risk (AER) of suicide were estimated. FINDINGS: From the included cases, 14,423 cancer patients were identified as having died by suicide, representing 0.26% of all deaths. We found that cancer patients had a higher risk of suicide compared with the general population, which equated to 0.8 excess deaths per 10,000 person-years. Greater suicide risk was correlated with the following: specific cancer sites, male sex, American Indian/Alaskan Native ancestry, being divorced, being uninsured, distance of metastasis, aged between 60 and 69 at diagnosis, and having a more recent diagnosis. The greatest SMR and AER were found in patients with cancers of the respiratory system, followed by those of the oral cavity and pharynx, myeloma, bones and joints, digestive system, and brain and other nervous system cancers. INTERPRETATION: Suicide risk among cancer patients varies greatly and depends on both disease type and patient characteristics. A tailored clinical management should be considered for patients at a higher risk of suicide. FUNDING: Natural Science Foundation of China.

Clinical outcomes and patient satisfaction with the use of biological and synthetic meshes in one-stage implant-based breast reconstruction.

BACKGROUND: Biological and synthetic meshes were used to cover the damaged muscle and augment the subpectoral pocket in breast reconstruction. However, few studies have directly compared the effects of biological and synthetic meshes. This study analyzed postoperative complications and assessed the patient-reported outcomes with the use of BioDesign® Surgisis and TiLOOP Bra/TiMesh® in one-stage implant-based breast reconstruction. METHODS: Patients undergoing one-stage implant-based breast reconstruction were enrolled in this study. Post-mastectomy breast reconstructions were facilitated with either Surgisis mesh or TiLOOP mesh. Complications were examined and patient-reported quality-of-life outcomes were evaluated using the BREAST-Q questionnaire (ver 2.0). The multivariate linear regression models were used for data analysis. RESULTS: Overall, 79 of 116 patients (68%) received breast reconstruction with Surgisis mesh and 37 (32%) with TiLOOP mesh. There was no difference in complication rates between the two groups postoperatively. But patient-reported satisfaction was higher with the use of Surgisis mesh than with TiLOOP mesh (P = 0.05). CONCLUSIONS: This study reported no difference between the Surgisis group and the TiLOOP group in either complication rates or most patient-reported outcomes postoperatively. Yet the assessment of patient-reported satisfaction showed preference toward Surgisis mesh, a finding with a potential implication for mesh selection.

Prognostic Value and Clinical Significance of LIPH in Breast Cancer.

BACKGROUND: Lipase member H (LIPH), a novel member of the mammalian triglyceride lipase family, is localized on human chromosome 3q27-q28. Exploration of the importance of the new cancer-related gene LIPH in several carcinomas has been reported in previous studies. Our study aims to systematically assess the expression pattern of LIPH in breast cancer. METHODS: Our study explored 2994 breast cancer samples with transcriptome data from the Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets. We systematically evaluated the mRNA expression of LIPH in breast cancer and the overall survival (OS) of patients. The protein expression of LIPH in breast cancer was evaluated with the Human Protein Atlas. We also explored the relationship between LIPH and the immune microenvironment in pan-cancer. RESULTS: Both mRNA and protein expression LIPH were found to be upregulated in breast cancer tumors. The overall survival rate of patients with high LIPH expression was lower than those of patients with low LIPH expression in both the TCGA dataset (p=0.0067) and METABRIC dataset (p<0.0001). Outcomes of the multivariate analysis found that the level of LIPH expression was an independent prognostic factor in both TCGA (p=0.001) and METABRIC (p=0.019) databases. The outcomes of the univariate analysis showed that LIPH was an important prognostic factor (p=0.01 in TCGA dataset, p=0.001 in METABRIC dataset). In the TCGA dataset, outcomes showed that LIPH expression was negatively correlated with the AJCC (American Joint Committee on Cancer) stage (p=2.3e-05) and triple-negative breast cancer (TNBC) tissues (p=3.1e-10). High LIPH expression showed lower OS in the TNBC subtype (P=0.011). CONCLUSION: Compared to normal tissues, the expression of LIPH was higher in breast cancer tissues in both mRNA and protein levels. This study showed that the high level of LIPH expression might be related to the worse prognosis of breast cancer.

Research Progresses in Immunological Checkpoint Inhibitors for Breast Cancer Immunotherapy.

Tumor immune escape refers to the phenomenon in which tumor cells escape the recognition and attack of the body's immune system through various mechanisms so that they can survive and proliferate in vivo. The imbalance of immune checkpoint protein expression is the primary mechanism for breast cancer to achieve immune escape. Cytotoxic T lymphocyte antigen 4 (CTLA4) and programmed cell death protein 1 (PD-1)/programmed cell death protein-ligand 1 (PD-L1) are critical immune checkpoints for breast cancer. Immune checkpoint inhibitors block the checkpoint and relieve its inhibition effect on immune cells, reactivate T-cells and destroy cancer cells and restore the body's ability to resist tumors. At present, immunological checkpoint inhibitors have made significant progress in breast cancer immunotherapy, and it is expected to become a new treatment for breast cancer.

Prolactin and endocrine therapy resistance in breast cancer: The next potential hope for breast cancer treatment.

Breast cancer, a hormone-dependent tumour, generally includes four molecular subtypes (luminal A, luminal B, HER2 enriched and triple-negative) based on oestrogen receptor, progesterone receptor and human epidermal growth factor receptor-2. Multiple hormones in the body regulate the development of breast cancer. Endocrine therapy is one of the primary treatments for hormone-receptor-positive breast cancer, but endocrine resistance is the primary clinical cause of treatment failure. Prolactin (PRL) is a protein hormone secreted by the pituitary gland, mainly promoting mammary gland growth, stimulating and maintaining lactation. Previous studies suggest that high PRL levels can increase the risk of invasive breast cancer in women. The expression levels of PRL and PRLR in breast cancer cells and breast cancer tissues are elevated in most ER+ and ER- tumours. PRL activates downstream signalling pathways and affects endocrine therapy resistance by combining with prolactin receptor (PRLR). In this review, we illustrated and summarized the correlations between endocrine therapy resistance in breast cancer and PRL, as well as the pathophysiological mechanisms and clinical practices. The study on PRL and its receptor would help explore reversing endocrine therapy-resistance for breast cancer.

[Research Progress of Discoidin Domain Receptor 1 in Breast Cancer and Other Malignant Tumors].

Discoidin domain receptor 1(DDR1)is a critical member of the receptor tyrosine kinase family.It may be related to tumor invasion and metastasis,and the abnormal activation of DDR1 can lead to the occurrence and development of malignant tumors,inflammation,and fibrosis.DDR1 are involved in cell adhesion,migration,proliferation,secretion of cytokines,and remodeling of extracellular matrix,thus playing a critical role in various pathophysiological processes of the human body.In this review,we demonstrate the research progress of DDR1 in breast cancer and other malignant tumors,in order to provide a new theoretical basis for the prevention and treatment of breast cancer and other tumors.

Biological Matrix-Assisted One-Stage Implant-Based Breast Reconstruction Versus Two-Stage Implant-Based Breast Reconstruction: Patient-Reported Outcomes and Complications.

BACKGROUND: Biological matrix-assisted one-stage implant-based breast reconstruction (IBBR) could improve the inframammary fold to achieve good esthetic results. However, whether biological matrix-assisted one-stage IBBR yields better postoperative outcomes compared with two-stage IBBR remains unclear. We aimed to compare and analyze surgical complications and patient-reported outcomes (PROs) based on the BREAST-Q version 2.0 questionnaire between biological matrix-assisted one-stage IBBR and traditional two-stage IBBR. METHODS: From May 2015 to June 2019, eligible patients who underwent SIS matrix-assisted one-stage IBBR or two-stage IBBR were enrolled in this retrospective cohort study. PROs were measured with BREAST-Q version 2.0, which scored the health-related quality of life, satisfaction, and experience domains. Complications were divided into major complications (patients requiring reoperation) and minor complications (patients who could be treated in the dressing room). PROs and complications were compared between the SIS matrix-assisted one-stage IBBR and two-stage IBBR groups. A multivariate linear regression analysis was used to identify the social and surgical factors that affected PROs. RESULTS: At our institution, 124 eligible patients were recruited. Seventy-nine patients (63.7%) underwent SIS matrix-assisted one-stage IBBR reconstruction, and 45 patients (36.3%) underwent tissue expander/implant reconstruction (two-stage IBBR). Postoperative BREAST-Q version 2.0 was completed by 68 of 79 patients (86.1%) in the SIS matrix-assisted one-stage IBBR group and by 35 of 45 patients (77.8%) in the two-stage IBBR group. In the satisfaction-related quality of life domain, satisfaction with breast was 9.27 points higher in the SIS matrix-assisted one-stage IBBR group (p = 0.012) compared with the two-stage IBBR group. The multivariate linear regression analysis showed that implant volume (p = 0.031) and postoperative radiotherapy (p = 0.036) significantly influenced the PRO of satisfaction with breast. However, patients in the SIS matrix-assisted one-stage IBBR group had a higher minor complication rate compared with patients in the two-stage IBBR group (p = 0.026). CONCLUSIONS: Our retrospective study showed that although patients treated with biological matrix-assisted one-stage IBBR tended to have higher postoperative complication rates, this technique correlated with better PROs compared with two-stage IBBR. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Efficacy and Safety of Anti-PD-1/ PD-L1 Monotherapy for Metastatic Breast Cancer: Clinical Evidence.

Background: Success has been reported in PD-1/PD-L1 blockade via pembrolizumab, atezolizumab, or avelumab monotherapy in manifold malignancies including metastatic breast cancer. Due to lack of large-scale study, here we present interim analyses to evaluate the safety and efficacy of these promising strategies in patients with advanced breast cancer. Methods: Six studies including 586 advanced breast cancer patients treated with anti-PD-1/PD-L1 monotherapy agents before July 1, 2020, were included. The anti-PD-1/PD-L1 agents include pembrolizumab, atezolizumab, land avelumab. Statistics was analyzed by R software and IBM SPSS Statistics 22. Results: Global analysis showed that for this monotherapy, the complete response was 1.26%, partial response was 7.65%, objective response rate (ORR) was 9.85%, and disease control rate (DCR) was 18.33%. 1-year overall survival rate and 6-month progression-free survival rate were 43.34 and 17.24%. Overall incidence of adverse events (AEs) was 64.18% in any grade and 12.94% in severe grade, while the incidence of immune-related AEs (irAEs) was approximately 14.75%: the most common treatment-related AEs of any grade that occurred in at least 5% of patients were arthralgia and asthenia; the most common severe treatment-related AEs occurred in at least 1% of patients were anemia and autoimmune hepatitis; the most common irAEs were hypothyroidism. Besides, the incidence of discontinue and death due to treatment-related AEs was about 3.06 and 0.31%, respectively. Additionally, by comparing efficacy indicators between PD-L1-positive and PD-L1-negative groups, an implicated correspondence between efficacy and the expression of PD-L1 biomarker was found: the PR was 9.93 vs 2.69%; the ORR was 10.62 vs. 3.07%; the DCR was 17.95 vs. 4.71%. Conclusion: Anti-PD-1/PD-L1 monotherapy showed a manageable safety profile and had a promising and durable anti-tumor efficacy in metastatic breast cancer patients. Higher PD-L1 expression may be closely correlated to a better clinical efficacy.