PD-L1 expression in tumor infiltrated lymphocytes predicts survival in triple-negative breast cancer

High CTLA-4 gene expression is an independent good prognosis factor in breast cancer patients, especially in the HER2-enriched subtype

BACKGROUND

Breast cancer (BC) is the most common cancer in women and the leading cause of cancer-related death worldwide. This heterogeneous disease has been historically considered a non-immunogenic type of cancer. However, recent advances in immunotherapy have increased the interest in knowing the role of the immune checkpoints (IC) and other immune regulation pathways in this neoplasia.

METHODS

In this retrospective study, we evaluated the correlation of mRNA expression of CTLA-4, PDCD1 (PD1), CD274 (PD-L1), PDCD1LG2 (PD-L2), CD276 (B7-H3), JAK2, and FOXO1 with clinicopathological factors and BC patient's outcome by real-time quantitative polymerase chain reaction (qPCR).

RESULTS

Our results showed that immunoregulatory gene expression depends on BC immunophenotype being CTLA-4 and PDCD1 (PD1) overexpressed on triple-negative/basal-like (TN/BL) and luminal B/HER2-positive phenotypes, respectively, and CD276 (B7-H3), JAK2 and FOXO1 associated with both luminal A and luminal B/HER2-negative tumors. In addition, we found that these genes can also be related to aggressive and non-aggressive clinicopathological characteristics in BC. Finally, survival analysis showed that CTLA-4 expression levels emerge as a significant independent factor of good prognosis in BC patients, especially in the HER2-enriched subtype.

CONCLUSION

Considering all these data, we can conclude that the expression of immunoregulatory genes depends on tumor phenotype and has potential clinical implications in BC patients.

PD-L1 protein expression in breast cancer

AIMS

The immune checkpoint marker, Programmed cell death-ligand 1 (PD-L1), is expressed by both cancer epithelial cells and tumour-infiltrating immune cells (TICs) thus constituting a potential target for immunotherapy. This is of particular interest in triple negative breast cancer. In this study, we assessed the prognostic value of PD-L1 expression in tumour epithelial cells and TICs in a series of patients with breast cancer with long-term follow-up, and associations between PD-L1 expression and histopathological type and grade, proliferation and molecular subtype.

METHODS

Using immunohistochemistry for PD-L1 in tissue microarrays, we assessed PD-L1 expression in 821 tumours. Expression of PD-L1 was assessed separately in the epithelial and stromal compartments and classified as <1%, ≥1% to <10% or ≥10% positive staining cells. We correlated PD-L1 expression in tumour epithelial cells and TICs with tumour characteristics using Pearson's χ2 test, and prognosis by cumulative incidence of death from breast cancer and Cox regression analyses.

RESULTS

We found membranous staining in ≥1% of tumour epithelial cells in 53/821 cases (6.5%). Of these, 21 (2.6%) were ≥10%. Among TICs, staining (≥1%) was seen in 144/821 cases (17.6%). Of these, 62 were ≥10% (7.6%). PD-L1 was associated with high histopathological grade and proliferation, and the medullary and metaplastic patterns. In TICs, PD-L1 ≥1% found in 22/34 (34.4%) human epidermal growth factor receptor 2 type and 29/58 (50%) basal phenotype. An independent association between PD-L1 expression and prognosis was not observed.

CONCLUSIONS

PD-L1 is expressed more frequently in TICs than tumour epithelial cells. Expression in TICs is associated with aggressive tumour characteristics and non-luminal tumours but not with prognosis.

The Prevalence of PD-L1 Expression in Triple-Negative Breast Cancer Patients and Its Correlation with Survival Rates and Other Prognostic Factors: A Survival Analysis

Background

Triple-negative breast cancer (TNBC) is a leading cause of cancer-related mortality among women, with a poor prognosis. The programmed cell death 1 (PD-1) pathway has emerged as a potential immunotherapy target. This study aimed to assess PD-L1 expression in TNBC patients and its relationship with prognostic variables.

Materials and Methods

This cross-sectional study included 107 TNBC patients recruited between 2016 and 2020. Patient age, tumor grade, and Ki67 expression were obtained from pathology reports. Immunohistochemistry was utilized to determine PD-L1 status, and 2-year survival data were collected through telephone follow-up.

Results

PD-L1 expression frequency in TNBC patients was 76.6%. Grade 3 was the most common cancer grade, significantly more prevalent in the PD-L1 positive group (P = 0.01). High Ki67 expression (≥14%) was observed in 89% of patients, significantly higher in the PD-L1 positive group (P = 0.003). The 2-year survival rates for the PD-L1 positive and negative groups were 84.1% and 92%, respectively, with no significant difference between the groups (P = 0.512).

Conclusion

This study investigated PD-L1 expression prevalence in TNBC patients and its correlation with prognostic variables. PD-L1 expression was associated with higher tumor grade and elevated Ki67 expression, indicating a potential role in tumor aggressiveness. However, despite these associations, PD-L1 expression did not significantly impact the 2-year survival rate in TNBC patients. These results emphasize the complexity of the immune microenvironment in TNBC and the necessity for further research to elucidate the precise role of PD-L1 in disease progression and patient outcomes.

Low progesterone receptor levels in high-grade DCIS correlate with HER2 upregulation and the presence of invasive components

Objective

In this study, we investigated pivotal molecular markers in human high-grade breast ductal carcinoma in situ (DCIS). Expression status of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth receptor 2 (HER2) was measured among various subtypes (Luminal (Lum) A, LumB HER2-, LumB HER2+, HER2-enriched and triple-negative).

Methods

In total, 357 DCIS cases were classified into respective subtypes, according to the 2013 St. Gallen guidelines. Each subtype was categorized into three subcategories: "Pure" (those without an invasive component), "W/invasive" (those with an invasive component), and "All" (the entire group of the given subtype). ER and PR expression were registered as intervals. Equivocal HER2 immunohistochemistry (IHC) cases (2+) were further investigated using dual-color in situ hybridization.

Results

The majority of patients (71%) were over the age of 50. We discovered no significant differences in the proportion of age between the "Pure" and "W/invasive" groups. There was no significant difference in ER/PR expression between "Pure" luminal subtypes of DCIS and "W/invasive" cases. We compared the HER2 IHC scores of "0", "1+", and "2+" among LumA and LumB HER2 subtypes and identified no statistically significant differences between "Pure" and "W/invasive" (p = 0.603). ER and PR expression ≥ 50% cutoff value was present in > 90% of all LumA cases. The incidences of cases with ER expression at cutoff values of < 10% and ≥ 50% in LumA were significantly different compared to other luminal subtypes (p < 0.0001). The proportion of cases with PR expression < 20% showed significant differences in the various luminal subtypes. In luminal B subtypes, low PR expression (< 20%) was significantly associated with both strong HER2 expression (3+) and the presence of an invasive component (p = 0.0001 and p = 0.0365, respectively).

Conclusions

ER and PR expression at ≥ 50% cutoff values were found in more than 90% of LumA cases. Samples with ER < 10% and ≥ 50% in LumA were significantly different compared to other luminal subtypes (p < 0.0001). Low PR expression in high-grade DCIS was strongly associated with HER2 overexpression (3+) and an invasive component (p = 0.0001 and p = 0.0365, respectively).

PD-L1 (SP142) Expression in Primary and Recurrent/Metastatic Triple-Negative Breast Cancers and Its Clinicopathological Significance

PURPOSE

The programmed death-ligand 1 (PD-L1) SP142 assay identifies patients with triple-negative breast cancer (TNBC) who are most likely to respond to the anti-PD-L1 agent atezolizumab. We aimed to compare PD-L1 (SP142) expression between primary and recurrent/metastatic TNBCs and elucidate the clinicopathological features associated with its expression.

MATERIALS AND METHODS

Primary and recurrent/metastatic TNBCs tested with PD-L1 (SP142) were collected, and clinicopathological information of these cases was obtained through a review of slides and medical records.

RESULTS

PD-L1 (SP142) positivity was observed in 50.9% (144/283) of primary tumors and 37.8% (31/82) of recurrent/metastatic TNBCs with a significant difference. Recurrent or metastatic sites were associated with PD-L1 positivity, with high PD-L1 positivity in the lung, breast, and soft tissues, and low positivity in the bone, skin, liver, and brain. When comparing PD-L1 expression between primary and matched recurrent/metastatic TNBCs using 55 paired samples, 20 cases (36.4%) showed discordance; 10 cases revealed positive conversion, and another 10 cases revealed negative conversion during metastatic progression. In primary TNBCs, PD-L1 expression was associated with a higher histologic grade, lower T category, pushing border, and higher tumor-infiltrating lymphocyte infiltration. In survival analyses, PD-L1 positivity, especially high positivity, was found to be associated with favorable prognosis of patients.

CONCLUSION

PD-L1 (SP142) expression was lower in recurrent/metastatic TNBCs, and substantial cases showed discordance in its expression between primary and recurrent/metastatic sites, suggesting that multiple sites may need to be tested for PD-L1 (SP142) when considering atezolizumab therapy. PD-L1 (SP142)-positive TNBCs seems to be associated with favorable clinical outcomes.

Is Programmed Death-Ligand 1 of Prognostic Significance in Triple-Negative Female Mammary Carcinoma?

Introduction

The most widespread female malignancy is breast cancer (BC), considerable percentage of patients with triple-negative BC (TNBC) experience rapid progression, recurrence, and metastasis. BC has not historically been treated as an immunogenic cancer. Nonetheless, several researchers have started to concentrate on immunotherapy.

Aim

The aim of the study is to investigate the immunohistochemical (IHC) expression of programmed death-ligand 1 (PD-L1) by stromal tumor-infiltrating lymphocytes (TILs) and tumor cells (TC) in female (TNBC) and to correlate with pathological features of such tumors, particularly those determine biologic behavior, such as the grade and stage the overall survival.

Methodology

This is a retrospective study which includes 49 paraffin-embedded tumor tissue sections which were collected from breast surgery specimens either radical or conservative of female patients with TNBC. The samples were analyzed immunohistochemically for PD-L1 expression.

Results

There were statistically significant relations among TC PD-L1 expression and TILs PD-L1 expression as well as relations among TILs PD-L1 expression with histologic grade, stromal TILs, and Ki-67 were statistically significant. Correlations between TC PD-L1 expression and N stage, histologic grade, and anatomic stage were statistically significant. Improved survival was detected within TILs PD-L1-positive cases; however, the correlation between the overall survival and PD-L1 expression in both TCs and stromal TIL was not statistically significant.

Conclusion

PD-L1 expressed in tumors with poor prognostic features such as the high grade, advanced T stage, and high Ki-67 index, TILs PD-L1-positive cases experienced improved survival supporting its prognostic significance. However, the correlation with overall survival was not statistically significant.

Piezo1 facilitates optimal T cell activation during tumor challenge

Functional effector T cells in the tumor microenvironment (TME) are critical for successful anti-tumor responses. T cell anti-tumor function is dependent on their ability to differentiate from a naïve state, infiltrate into the tumor site, and exert cytotoxic functions. The factors dictating whether a particular T cell can successfully undergo these processes during tumor challenge are not yet completely understood. Piezo1 is a mechanosensitive cation channel with high expression on both CD4+ and CD8+ T cells. Previous studies have demonstrated that Piezo1 optimizes T cell activation and restrains the CD4+ regulatory T cell (Treg) pool in vitro and under inflammatory conditions in vivo. However, little is known about the role Piezo1 plays on CD4+ and CD8+ T cells in cancer. We hypothesized that disruption of Piezo1 on T cells impairs anti-tumor immunity in vivo by hindering inflammatory T cell responses. We challenged mice with T cell Piezo1 deletion (P1KO) with tumor models dependent on T cells for immune rejection. P1KO mice had the more aggressive tumors, higher tumor growth rates and were unresponsive to immune-mediated therapeutic interventions. We observed a decreased CD4:CD8 ratio in both the secondary lymphoid organs and TME of P1KO mice that correlated inversely with tumor size. Poor CD4+ helper T cell responses underpinned the immunodeficient phenotype of P1KO mice. Wild type CD8+ T cells are sub-optimally activated in vivo with P1KO CD4+ T cells, taking on a CD25loPD-1hi phenotype. Together, our results suggest that Piezo1 optimizes T cell activation in the context of a tumor response.

Breaking Tumor Immunosuppressive Network by Regulating Multiple Nodes with Triadic Drug Delivery Nanoparticles

Inside the tumor microenvironment, a complicated immunosuppressive network is constituted by tumor cells and suppressive immune cells as its nodes, including myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and regulatory T cells, which have mutual promotion on each other and superimposed inhibition on natural killer (NK) cells and cytotoxic T cells. Breaking the whole balance of this web is critical to tumor immunotherapy since modulation on a single node may be diluted by other factors in the network. To achieve multifaceted regulation on antitumor immunity against triple-negative breast cancer, in this work, a micelle, termed BEM, co-delivering the MDSC inhibitor, entinostat (ENT), and the immune checkpoint inhibitor, BMS-1, was constructed with pH-sensitive amphiphilic poly(β-amino ester) derivatives. Then, BEM and the scavenger receptor A (SR-A) ligand dextran sulfate (DXS) formed a negatively charged nanoparticle (BEN). DXS detached from BEN in the weakly acidic tumor microenvironment and blocked SR-A on TAMs, reprogramming TAMs toward the M1 type. The positively charged BEM with facilitated intratumoral penetration and cellular uptake dissociated in the lysosomes, accompanied by the release of ENT and BMS-1 to suppress MDSCs and block the programmed cell death protein (PD)-1/PD-ligand 1 pathway, respectively. As a result, NK cells and CD8+ T cells in tumors were increased, as were their effector cytokines. The activated innate and adaptive antitumor immune responses suppressed the growth and metastasis of tumors and prolonged survival of 4T1 tumor-bearing mice. BEN provides a reliable approach for improving cancer immunotherapy by destroying the immunosuppression web in tumors via multinode regulation.

Disruption of RBMS3 suppresses PD-L1 and enhances antitumor immune activities and therapeutic effects of auranofin against triple-negative breast cancer

Programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) interaction exerts a vital role in tumor-associated immune evasion. While strategies disrupting PD-1/PD-L1 axis have shown clinical benefits in various cancers, the limited response rate prompts us to investigate the complex mechanisms underlying the molecular regulation of PD-L1. Here, we identify the RNA binding protein RBMS3 as a crucial PD-L1 regulator in triple-negative breast cancer (TNBC). Correlation analysis shows that Rbms3 significantly correlates with immunosuppressive CD274, Rbms1, NT5E and ENTPD1. RBMS3 protein binds to CD274 mRNA specifically in TNBC cells to increase PD-L1 levels. Mechanistically, RBMS3 stabilizes CD274 mRNA by interacting with its 3'UTR, which represents as an intrinsic cancer cell mechanism for driving PL-D1 upregulation in TNBC. RBMS3 depletion not only destabilizes the mRNA stability and protein expression of PD-L1, but also suppresses the migratory abilities of TNBC MDA-MB-231 cells. Importantly, combination of RBMS3 ablation with auranofin (AUF), an FDA-approved thioredoxin reductase inhibitor, facilitates anti-tumor T-cell immunity in vivo and improves AUF-mediated anti-cancer effect. Taken together, our findings reveal RBMS3 as a key post-transcriptional regulator of PD-L1 and how they contribute to immune escape in TNBC, which could lead to novel combinatorial therapeutic strategies to enhance the efficacy of cancer immunotherapy.

Immunotherapy in triple-negative breast cancer: Insights into tumor immune landscape and therapeutic opportunities

Triple-negative breast cancer (TNBC) is a clinically aggressive subtype of breast cancer that represents 15-20% of breast tumors and is more prevalent in young pre-menopausal women. It is the subtype of breast cancers with the highest metastatic potential and recurrence at the first 5 years after diagnosis. In addition, mortality increases when a complete pathological response is not achieved. As TNBC cells lack estrogen, progesterone, and HER2 receptors, patients do not respond well to hormone and anti-HER2 therapies, and conventional chemotherapy remains the standard treatment. Despite efforts to develop targeted therapies, this disease continues to have a high unmet medical need, and there is an urgent demand for customized diagnosis and therapeutics. As immunotherapy is changing the paradigm of anticancer treatment, it arises as an alternative treatment for TNBC patients. TNBC is classified as an immunogenic subtype of breast cancer due to its high levels of tumor mutational burden and presence of immune cell infiltrates. This review addresses the implications of these characteristics for the diagnosis, treatment, and prognosis of the disease. Herein, the role of immune gene signatures and tumor-infiltrating lymphocytes as biomarkers in TNBC is reviewed, identifying their application in patient diagnosis and stratification, as well as predictors of efficacy. The expression of PD-L1 expression is already considered to be predictive of response to checkpoint inhibitor therapy, but the challenges regarding its value as biomarker are described. Moreover, the rationales for different formats of immunotherapy against TNBC currently under clinical research are discussed, and major clinical trials are highlighted. Immune checkpoint inhibitors have demonstrated clinical benefit, particularly in early-stage tumors and when administered in combination with chemotherapy, with several regimens approved by the regulatory authorities. The success of antibody-drug conjugates and research on other emerging approaches, such as vaccines and cell therapies, will also be addressed. These advances give hope on the development of personalized, more effective, and safe treatments, which will improve the survival and quality of life of patients with TNBC.

Programmed death-ligand 1 (PD-L1) expression predicts response to neoadjuvant chemotherapy in triple-negative breast cancer: A systematic review and meta-analysis

Background: In patients with metastatic triple-negative breast cancer (TNBC), PD-L1 expression has been demonstrated to predict response to immunotherapy. It is unclear whether PD-L1 expression measured with currently available validated assays can predict chemotherapy response in patients with non-metastatic TNBC.Methods: We conducted a systematic review and meta-analysis of clinical studies to assess the PD-L1 expression as a predictor of response to chemotherapy in non-metastatic TNBC using validated assays. The primary endpoint was pathological complete response (pCR) rate to neoadjuvant chemotherapy. Secondary endpoints included the prevalence of PD-L1 expression in non-metastatic TNBC and its impact on disease-free survival (DFS) and overall survival (OS). Moreover, RNA sequence data from the TCGA breast cancer cohort was used to define the relationship between PDCD1 and response to chemotherapy and prognosis.Results: Nineteen studies were eligible for the meta-analysis with a total of 2403 patients with non-metastatic TNBC disease. The PD-L1-positive cohort had a significantly higher likelihood of achieving pCR with neoadjuvant chemotherapy (pooled odds ratio =1.95; 95% CI= 1.39-2.73, p <0.0001). In studies which reported long-term outcomes, PD-L1 positivity was associated with significantly better DFS and OS compared to PD-L1 negative patients (pooled hazard ratio= 0.51; 95% CI= 0.35-0.74, p< 0.0001 and 0.51; 95% CI= 0.27-0.94, p = 0.031, respectively). Transcriptomic data suggested that PD-L1 expression is a surrogate marker for the upregulation of key immune-related genes that mediate response to chemotherapy in TNBC.Conclusion: This analysis clearly shows that patients with PD-L1 positive TNBC respond better to neoadjuvant chemotherapy and are associated with better survival outcomes compared to patients with PD-L1 negative tumors. The newly distinct quadruple negative breast cancer (QNBC) subtype should be defined as the BC subtype with the poorest outcome in the non-metastatic setting, highlighting the need for more aggressive therapy approaches.

Prognostic Significance of Lymphocyte Infiltrate Localization in Triple-Negative Breast Cancer

High infiltration by tumor-infiltrating lymphocytes (TILs) is associated with favorable prognosis in different tumor types, but the clinical significance of their spatial localization within the tumor microenvironment is debated. To address this issue, we evaluated the accumulation of intratumoral TILs (itTILs) and stromal TILs (sTILs) in samples from 97 patients with early triple-negative breast cancer (TNBC) in the center (sTIL central) and periphery (sTIL peripheral) of tumor tissues. Moreover, the presence of primary and secondary lymphoid aggregates (LAs) and the expression levels of the cancer testis antigen (CTA), NY-ESO-1, and PD-L1 were explored. High infiltration by itTILs was observed in 12/97 samples (12.3%), unrelated to age, Ki67 expression, tumor size, histologic type and grade, and LA presence. NY-ESO-1 was expressed in tumor cells in 37 samples (38%), with a trend suggesting a correlation with itTIL infiltration (p = 0.0531). PD-L1 expression was detected in immune cells in 47 samples (49%) and was correlated with histologic grade, sTILs, and LA formation. The presence of primary LAs was significantly correlated with better disease-free survival (DFS) (p = 0.027). Moreover, no tumor progression was observed during >40 months of clinical follow up in the 12 patients with high itTILs or in the 14 patients with secondary LAs. Thus, careful evaluation of lymphoid infiltrate intratumoral localization might provide important prognostic information.

c-Met up-regulates the expression of PD-L1 through MAPK/NF-κBp65 pathway

Sorafenib acquired drug resistance during the treatment of hepatocellular carcinoma (HCC) reduces the efficacy of the drug. The immune escape effect induced by PD-L1 is largely associated with drug resistance of HCC. However, the regulated mechanism of PD-L1 is unclear. This research aimed to clarify the control mechanism of PD-L1. c-Met was found abnormally highly expressed in Huh-7^SR with high PD-L1 expression. In addition, c-Met, as the upstream target molecule of PD-L1, promoted the proliferation and migration of HCC in vitro and in vivo. We also found that c-Met activated the MAPK signaling pathway and the downstream NF-κBp65 transcription factor, which interacts with the proximal region of the PD-L1 promoter to promote PD-L1 expression. In conclusion, c-Met regulates the transcription of PD-L1 through the MAPK/NF-κBp65 pathway, thereby promoting the progress of HCC. The role of c-Met and PD-L1 in HCC needs to be further studied, but it is a potential target for the treatment of HCC. KEY MESSAGES: In the study, it was found that c-Met is also abnormally highly expressed in Huh-7^SR with high PD-L1 expression and can promote the development of HCC in vitro and in vivo. PD-L1 and c-Met expression levels are positively correlated. In the follow-up mechanism study, we found that c-Met activated the MAPK signaling pathway and subsequently activated the downstream NF-κBp65 transcription factor, which interacts with the proximal region of the PD-L1 promoter to promote PD-L1 expression. Our study found that c-Met regulates the transcription of PD-L1 through the MAPK/NF-κBp65 pathway, thereby promoting the progress of HCC.

OUP accepted manuscript

Background

PD-L1 has been used as a biomarker to select patients for treatment of PD-1/PD-L1 inhibitors.

Materials and Methods

In this study, we assessed the clinicopathological features of breast cancers that are associated with PD-L1 expression, as well as its relationship with other immune components and its prognostic significance.

Results

Totally 1752 cases were included in this cohort. PD-L1 expression in tumor-infiltrating immune cells (PD-L1-IC) expression and in tumor cells (PD-L1-TC) expression were identified in 34.2% and 10.1% of cases, respectively, and they showed a positive correlation with higher tumor grade, morphological apocrine features, presence of necrosis, and higher stromal tumor-infiltrating lymphocytes (sTIL). PD-L1-IC and PD-L1-TC expression correlated positively with each other, and both of them were negatively associated with estrogen receptor and progesterone receptor and positively associated with Ki67, HER2, EGFR, p63, and p-cadherin. In survival analysis, PD-L1-IC expression was associated with better disease-free survival (DFS) and breast cancer-specific survival (BCSS) in HER2-overexpressed (HER2-OE) cancers and high–grade luminal B cancers. In triple–negative breast cancers (TNBC) and HER2–OE cancers, compared with sTIL low PD-L1-IC negative cases, sTIL high cases showed significantly better DFS independent of PD-L1-IC status. sTIL low PD-L1-IC positive cases also demonstrated a better DFS in HER2–OE cancers. In high–grade luminal B cancers, sTIL high PD-L1-IC positive cases showed the best BCSS.

Conclusion

The data suggested that the combining analysis of sTIL and PD-L1-IC expression refined the prognostication of breast cancer subtypes. Cases with high TIL and PD-LI-IC expression appear to be more immune active.

Future of PD-1/PD-L1 axis modulation for the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) has the worst prognosis among the subtypes of breast cancer, with no targeted therapy available. Immunotherapy targeting programmed cell death protein-1 (PD-1) and its ligand (PD-L1) has resulted in some promising outcomes in cancer patients. The common treatments are monoclonal antibodies (mAbs). Despite novel methodologies in developing mAbs, there are several drawbacks with these medications. Immunological reactions, expensive and time-consuming production and requiring refrigeration are some of the challenging characteristics of mAbs that are addressed with using aptamers. Aptamers are nucleotide-based structures with high selectivity and specificity for target. Their small size helps aptamers penetrate the tissue better. In this review, we have discussed the nature of PD-1/PD-L1 interaction and summarised the available mAbs and aptamers specific for these two targets. This review highlights the role of aptamers as a future pathway for PD-1/PD-L1 modulation.

T-regulatory cells predict clinical outcome in soft tissue sarcoma patients: a clinico-pathological study

BACKGROUND

Soft tissue sarcomas (STS) are generally considered non-immunogenic, although specific subtypes respond to immunotherapy. Antitumour response within the tumour microenvironment relies on a balance between inhibitory and activating signals for tumour-infiltrating lymphocytes (TILs). This study analysed TILs and immune checkpoint molecules in STS, and assessed their prognostic impact regarding local recurrence (LR), distant metastasis (DM), and overall survival (OS).

METHODS

One-hundred and ninety-two surgically treated STS patients (median age: 63.5 years; 103 males [53.6%]) were retrospectively included. Tissue microarrays were constructed, immunohistochemistry for PD-1, PD-L1, FOXP3, CD3, CD4, and CD8 performed, and staining assessed with multispectral imaging. TIL phenotype abundance and immune checkpoint markers were correlated with clinical and outcome parameters (LR, DM, and OS).

RESULTS

Significant differences between histology and all immune checkpoint markers except for FOXP3+ and CD3-PD-L1+ cell subpopulations were found. Higher levels of PD-L1, PD-1, and any TIL phenotype were found in myxofibrosarcoma as compared to leiomyosarcoma (all p < 0.05). The presence of regulatory T cells (Tregs) was associated with increased LR risk (p = 0.006), irrespective of margins. Other TILs or immune checkpoint markers had no significant impact on outcome parameters.

CONCLUSIONS

TIL and immune checkpoint marker levels are most abundant in myxofibrosarcoma. High Treg levels are independently associated with increased LR risk, irrespective of margins.

Cyclin B2 (CCNB2) Stimulates the Proliferation of Triple-Negative Breast Cancer (TNBC) Cells In Vitro and In Vivo

Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer. Currently, targeting therapy makes great advances for the treatment of TNBC, whereas more effective therapeutic targets are urgently needed. Cyclin B2 (CCNB2), which belongs to B-type cyclins, is known as a cell cycle regulator. CCNB2 is synthesized at G1 phase in cancer cells and downregulated at anaphase. The defects of CCNB2 led to the abnormal cell cycle and tumorigenesis. Though there are wide effects of CCNB2 on multiple types of tumors, the potential role of CCNB2 in TNBC progression is still unclear. Herein, we found that CCNB2 was highly expressed in human TNBC tissues and correlated with the prognosis and clinical pathological features including tumor size (p = 0.022^∗) and pTNM stage (p = 0.021^∗) of patients with TNBC. CCNB2 could promote the proliferation of TNBC cells in vitro and in mice. Our findings therefore confirmed the involvement of CCNB2 in TNBC progression and provided the evidence that CCNB2 could serve as a promising molecular target of TNBC.

Clinicopathological and prognostic significance of programmed cell death ligand 1 expression in patients diagnosed with breast cancer: meta-analysis

BACKGROUND

Uncertainty exists regarding the clinical relevance of programmed cell death ligand 1 (PD-L1) expression in breast cancer.

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Observational studies that compared high versus low expression of PD-L1 on breast cancer cells were identified. Log hazard ratios (HRs) for disease-free and overall survival and their standard errors were calculated from Kaplan-Meier curves or Cox regression analyses, and pooled using the inverse-variance method. Dichotomous variables were pooled as odds ratios (ORs) using the Mantel-Haenszel method.

RESULTS

Sixty-five studies with 19 870 patients were included; 14 404 patients were classified as having low and 4975 high PD-L1 expression. High PD-L1 was associated with achieving a pathological complete response following neoadjuvant chemotherapy (OR 3.30, 95 per cent confidence interval 1.19 to 9.16; P < 0.01; I2 = 85 per cent). Low PD-L1 expression was associated with human epidermal growth factor receptor 2 (OR 3.98, 1.81 to 8.75; P < 0.001; I2 = 96 per cent) and luminal (OR 14.93, 6.46 to 34.51; P < 0.001; I2 = 99 per cent) breast cancer subtypes. Those with low PD-L1 had favourable overall survival rates (HR 1.30, 1.05 to 1.61; P = 0.02; I2 = 85 per cent).

CONCLUSION

Breast cancers with high PD-L1 expression are associated with aggressive clinicopathological and immunohistochemical characteristics and are more likely to achieve a pathological complete response following neoadjuvant chemotherapy. These breast cancers are, however, associated with worse overall survival outcomes.

Immune checkpoint inhibitors for triple-negative breast cancer: From immunological mechanisms to clinical evidence

Breast cancer is the most common cancer type in women worldwide. Triple-negative breast cancer (TNBC), which is characterized by the absence of estrogen receptor/progesterone receptor (ER/PR) and human epidermal growth factor receptor 2 (Her2) expressions, has a poorer prognosis compared with non-TNBC breast tumors. Until recently systemic treatment for TNBC was confined to chemotherapy owing to the lack of actionable targets. Immune checkpoint molecules are expressed on malignant cells or tumor-infiltrating immune cells and can inhibit anti-cancer immune responses. Immune checkpoint inhibitors (ICI), including anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death protein 1 (PD-1), and anti-programmed cell death 1 ligand 1 (PD-L1), induce immune responses in different types of neoplasms. They have recently gained attention for their possible role in TNBC treatment. Several clinical trials have been conducted on the role of immune checkpoint blockade in different settings for TNBC treatment. Available evidence justifies the application of ICI and chemotherapy combination in the management of metastatic TNBC and early-stage TNBC in neoadjuvant setting. This study aims to provide information on the mechanisms of action of ICIs, review the efficacy results of clinical trials using ICIs for TNBC treatment, and assess the side effects of such drugs.

Prognostic and Clinicopathologic Associations of LAG-3 Expression in Triple-negative Breast Cancer

The immune checkpoint molecule lymphocyte activation gene 3 (LAG-3) is currently being investigated as a possible target for immunotherapy in triple-negative breast cancer (TNBC), frequently as an addition to treatment with programmed cell death protein 1/programmed death ligand 1 (PD-L1) inhibition. However, expression of LAG-3, the frequency of coexpression with PD-L1, and the prognostic significance of this marker have not been studied extensively in TNBC. For this study, tissue microarrays (TMAs) were constructed from surgical specimens of 514 patients with TNBC. TMAs were stained immunohistochemically for LAG-3 and PD-L1 expression. Tumor-infiltrating lymphocytes (TILs) were evaluated on full glass slides. LAG-3 expression was significantly associated with improved overall survival and relapse-free survival. When adjusted for clinicopathologic factors, each increment of 10 LAG-3-positive intratumoral lymphocytes per TMA core was associated with improved overall survival (hazard ratio=0.93, 95% confidence interval: 0.89-0.97, P=0.002), and recurrence-free survival (hazard ratio=0.91, 95% confidence interval: 0.85-0.97, P=0.002). PD-L1 expression on immune cells and PD-L1 expression evaluated with the combined positive score and TILs were also associated with improved survival in both univariate and multivariate analyses. PD-L1 expression on tumor cells was only associated with improved survival in univariate analysis. LAG-3 expression was associated with both TILs and PD-L1 expression. Coexpression of LAG-3 and PD-L1 did not confer additional survival benefits. In conclusion, LAG-3 expression is associated with improved survival in TNBC. LAG-3 is often coexpressed with PD-L1, confirming that TNBC is likely a suitable candidate for cotreatment with LAG-3 and programmed cell death protein 1/PD-L1 inhibitors. However, coexpression does not confer additional survival benefits.

How can artificial intelligence models assist PD-L1 expression scoring in breast cancer: results of multi-institutional ring studies

Programmed death ligand-1 (PD-L1) expression is a key biomarker to screen patients for PD-1/PD-L1-targeted immunotherapy. However, a subjective assessment guide on PD-L1 expression of tumor-infiltrating immune cells (IC) scoring is currently adopted in clinical practice with low concordance. Therefore, a repeatable and quantifiable PD-L1 IC scoring method of breast cancer is desirable. In this study, we propose a deep learning-based artificial intelligence-assisted (AI-assisted) model for PD-L1 IC scoring. Three rounds of ring studies (RSs) involving 31 pathologists from 10 hospitals were carried out, using the current guideline in the first two rounds (RS1, RS2) and our AI scoring model in the last round (RS3). A total of 109 PD-L1 (Ventana SP142) immunohistochemistry (IHC) stained images were assessed and the role of the AI-assisted model was evaluated. With the assistance of AI, the scoring concordance across pathologists was boosted to excellent in RS3 (0.950, 95% confidence interval (CI): 0.936-0.962) from moderate in RS1 (0.674, 95% CI: 0.614-0.735) and RS2 (0.736, 95% CI: 0.683-0.789). The 2- and 4-category scoring accuracy were improved by 4.2% (0.959, 95% CI: 0.953-0.964) and 13% (0.815, 95% CI: 0.803-0.827) (p < 0.001). The AI results were generally accepted by pathologists with 61% "fully accepted" and 91% "almost accepted". The proposed AI-assisted method can help pathologists at all levels to improve the PD-L1 assay (SP-142) IC assessment in breast cancer in terms of both accuracy and concordance. The AI tool provides a scheme to standardize the PD-L1 IC scoring in clinical practice.

Determining Factors in the Therapeutic Success of Checkpoint Immunotherapies against PD-L1 in Breast Cancer: A Focus on Epithelial-Mesenchymal Transition Activation

Breast cancer is the most common neoplasm diagnosed in women around the world. Checkpoint inhibitors, targeting the programmed death receptor-1 or ligand-1 (PD-1/PD-L1) axis, have dramatically changed the outcome of cancer treatment. These therapies have been recently considered as alternatives for treatment of breast cancers, in particular those with the triple-negative phenotype (TNBC). A further understanding of the regulatory mechanisms of PD-L1 expression is required to increase the benefit of PD-L1/PD-1 checkpoint immunotherapy in breast cancer patients. In this review, we will compile the most recent studies evaluating PD-1/PD-L1 checkpoint inhibitors in breast cancer. We review factors that determine the therapeutic success of PD-1/PD-L1 immunotherapies in this pathology. In particular, we focus on pathways that interconnect the epithelial-mesenchymal transition (EMT) with regulation of PD-L1 expression. We also discuss the relationship between cellular metabolic pathways and PD-L1 expression that are involved in the promotion of resistance in TNBC.

Co-localization of CD169+ macrophages and cancer cells in lymph node metastases of breast cancer patients is linked to improved prognosis and PDL1 expression

Breast cancer is the most common form of cancer in women worldwide. Although the survival among breast cancer patients has improved, there is still a large group of patients with dismal prognosis. One of the most important prognostic factors for poor prognosis is lymph node metastasis. Increasing knowledge concerning the lymph nodes of breast cancer patients indicates that they are affected by the primary tumor. In this study we show that presence of CD169⁺ subcapsular sinus macrophages in contact with lymph node metastases in breast cancer patients, is related to better prognosis after adjuvant tamoxifen treatment, but only in patients with PDL1⁺ primary tumors. This is in contrast to the prognostic effect of CD169⁺ primary tumor-associated macrophages (TAMs). We further show that CD169⁺ macrophages were spatially associated with expression of PDL1 on nearby cells, both in primary tumors and metastatic lymph node, although PDL1 expression in metastatic lymph node as such did not have further prognostic impact. Our data suggest that CD169⁺ resident lymph node macrophages have a unique function in targeting immune responses against breast cancer and should be further investigated in detail.

PD-1 and PD-L1 expression in Kaposi sarcoma: A comparative study according to the pathological stage and clinical characteristics

BACKGROUND

Kaposi sarcoma (KS) is a mesenchymal tumor with distinct histopathological features according to stage of progression. Programmed death-1 (PD-1) and its ligand PD-L1 play major roles in the immune escape strategy of tumors.

OBJECTIVES

This study evaluated expression of PD-1 and PD-L1 in various stages of KS and investigated associations between their expression and clinical characteristics.

METHODS

Fifty cases with histopathologically diagnosed KS were classified as early or late stage. These specimens were stained with anti-PD-1 and anti-PD-L1 antibodies. The extent of expression in the intratumoral and peritumoral areas was judged by two dermatopathologists.

RESULTS

PD-1 and PD-L1 were expressed in 72.2% (13/18) and 11.1% (2/18) of early-stage cases, respectively, compared with 43.8% (14/32) and 28.1% (9/32) of late-stage cases, respectively. At the late stage, PD-1 expression was significantly higher in the peritumoral area than in the intratumoral area (P = 0.001). PD-1 expression in the intratumoral area was significantly higher at the early stage than at the late stage (P = 0.013). PD-L1 expression in the peritumoral area was significantly higher at the late stage than at the early stage (P = 0.038).

CONCLUSIONS

The pattern of PD-1 and PD-L1 expression differs according to the stage of KS, but is unaffected by clinical variables.

Cell Motility and Cancer

Cell migration is an essential systemic behavior, tightly regulated, of all living cells endowed with directional motility that is involved in the major developmental stages of all complex organisms such as morphogenesis, embryogenesis, organogenesis, adult tissue remodeling, wound healing, immunological cell activities, angiogenesis, tissue repair, cell differentiation, tissue regeneration as well as in a myriad of pathological conditions. However, how cells efficiently regulate their locomotion movements is still unclear. Since migration is also a crucial issue in cancer development, the goal of this narrative is to show the connection between basic findings in cell locomotion of unicellular eukaryotic organisms and the regulatory mechanisms of cell migration necessary for tumor invasion and metastases. More specifically, the review focuses on three main issues, (i) the regulation of the locomotion system in unicellular eukaryotic organisms and human cells, (ii) how the nucleus does not significantly affect the migratory trajectories of cells in two-dimension (2D) surfaces and (iii) the conditioned behavior detected in single cells as a primitive form of learning and adaptation to different contexts during cell migration. New findings in the control of cell motility both in unicellular organisms and mammalian cells open up a new framework in the understanding of the complex processes involved in systemic cellular locomotion and adaptation of a wide spectrum of diseases with high impact in the society such as cancer.