Prevalence Study of PD-L1 SP142 Assay in Metastatic Triple-negative Breast Cancer

Alteration of PD-L1 (SP142) status after neoadjuvant chemotherapy and its clinical significance in triple-negative breast cancer

PURPOSE

The tumor immune microenvironment can change after neoadjuvant chemotherapy (NAC) for triple-negative breast cancer (TNBC). We aimed to investigate the effects of NAC on PD-L1 (SP142) status and its clinical significance in TNBC.

METHODS

Paired samples of biopsy and resection specimens were collected from 182 patients with TNBC before and after NAC. PD-L1 (SP142) expression in immune cells in pre- and post-NAC breast cancer samples and the changes between them were analyzed, along with their relationships with the clinicopathological features and clinical outcomes of the patients.

RESULTS

Of the 182 patients, 61 (33.5%) achieved pathologic complete response (pCR) after NAC. PD-L1 (SP142) positivity, defined as immune cell staining in ≥ 1% of tumor area, was a predictor for pCR. PD-L1-positive immune cells significantly increased after NAC (2.8% to 5.2% on average) in 109 patients with measurable residual disease. Alteration of PD-L1 status was observed in 24 (22.0%) of the 109 patients with measurable residual tumors after NAC, and all PD-L1 status-converted patients, except one, revealed negative-to-positive conversion. Regarding chemotherapeutic agents, the use of platinum agents was associated with a significant increase in PD-L1-positive immune cells after NAC. In survival analyses, a positive PD-L1 status after NAC and increase of PD-L1-positive immune cells after NAC were associated with better recurrence-free survival of the patients.

CONCLUSION

PD-L1 (SP142) status changes after NAC, mostly as a positive conversion. As PD-L1 (SP142) status can convey prognostic and predictive information, it needs to be tested before and after NAC.

Navigating practical challenges in immunotherapy for metastatic triple negative breast cancer

Immunotherapy has revolutionized cancer therapy and now represents a standard of care for many tumor types, including triple-negative breast cancer. Despite the positive results that have led to the approval of immunotherapy in both early- and advanced-stage triple-negative breast cancer, pivotal clinical trials cannot address the myriad questions arising in everyday clinical practice, often falling short in delivering all the information that clinicians require. In this manuscript, we aim to address some of these practical questions, with the purpose of providing clinicians with a guide for optimizing the use of immune checkpoint inhibitors in the management of breast cancer patients and identifying opportunities for future research to clarify unresolved questions.

Programmed Death Ligand 1 (PD-L1) Expression in Lymphomas: State of the Art

The interaction of programmed death-1 (PD-1) on T lymphocytes with its ligands Programmed Death Ligand 1 (PD-L1) and Programmed Death Ligand 2 (PD-L2) on tumor cells and/or tumor-associated macrophages results in inhibitory signals to the T-cell receptor pathway, consequently causing tumor immune escape. PD-L1/PD-L2 are currently used as predictive tissue biomarkers in clinical practice. Virtually PD-L1 levels expressed by tumor cells are associated with a good response to immune checkpoint blockade therapies targeting the PD-1/PD-L1 axis. These therapies restore T-cell antitumor immune response by releasing T-lymphocytes from the inhibitory effects of tumor cells. Immune checkpoint therapies have completely changed the management of patients with solid cancers. This therapeutic strategy is less used in hematological malignancies, although good results have been achieved in some settings, such as refractory/relapsed classic Hodgkin lymphoma and primary mediastinal large B-cell lymphoma. Variable results have been obtained in diffuse large B-cell lymphoma and T-cell lymphomas. Immunohistochemistry represents the main technique for assessing PD-L1 expression on tumor cells. This review aims to describe the current knowledge of PD-L1 expression in various types of lymphomas, focusing on the principal mechanisms underlying PD-L1 overexpression, its prognostic significance and practical issues concerning the evaluation of PD-L1 immunohistochemical results in lymphomas.

A comprehensive single-cell breast tumor atlas defines epithelial and immune heterogeneity and interactions predicting anti-PD-1 therapy response

We present an integrated single-cell RNA sequencing atlas of the primary breast tumor microenvironment (TME) containing 236,363 cells from 119 biopsy samples across eight datasets. In this study, we leverage this resource for multiple analyses of immune and cancer epithelial cell heterogeneity. We define natural killer (NK) cell heterogeneity through six subsets in the breast TME. Because NK cell heterogeneity correlates with epithelial cell heterogeneity, we characterize epithelial cells at the level of single-gene expression, molecular subtype, and 10 categories reflecting intratumoral transcriptional heterogeneity. We develop InteractPrint, which considers how cancer epithelial cell heterogeneity influences cancer-immune interactions. We use T cell InteractPrint to predict response to immune checkpoint inhibition (ICI) in two breast cancer clinical trials testing neoadjuvant anti-PD-1 therapy. T cell InteractPrint was predictive of response in both trials versus PD-L1 (AUC = 0.82, 0.83 vs. 0.50, 0.72). This resource enables additional high-resolution investigations of the breast TME.

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.

PD-L1 testing in metastatic triple negative breast cancer: Results of an Italian survey

BACKGROUND

Immunotherapy has revolutionized the approach to metastatic triple-negative breast cancers. Atezolizumab was approved for patients with metastatic triple-negative breast cancers whose tumors express PD-L1, determined by SP 142 assay. To assess the availability and practice of SP142 test we administered a survey to all the 15 pathology departments of the Lazio Region during a six-month period.

METHODS

The survey comprised 12 questions regarding the availability of SP142 in the pathology departments, the percentage of positive tests, the difficulties of pathologists in cases close to cut-off value and the tested samples.

RESULTS

The SP142 assay was available in only eight centers. In case of positive result, most centers (5/8, 62.5%) reported values of PD-L1 expression ranging from > 1 to ⩽ 5%, with values close to the cut-off point (⩾ 1% or < 1%) being the greatest challenge.Most of the centers (6/8, 75%) tested material from both their own and other hospitals. In most centers, the evaluations were performed either on primary tumors or metastasis, in particular lymph nodes (5/8, 62.5%), followed by lung (3/8, 37.5%) and liver (1/8, 12.5%) metastasis.

CONCLUSION

Our results raise some important issues concerning the evaluation of PD-L1 in the "real-life" setting, providing strategies for its implementation.

Systemic Therapy for Metastatic Triple Negative Breast Cancer: Current Treatments and Future Directions

Until recently, despite its heterogenous biology, metastatic triple negative breast cancer (TNBC) was treated as a single entity, with successive lines of palliative chemotherapy being the only systemic option. Significant gene expression studies have demonstrated the diversity of TNBC, but effective differential targeting of the four main (Basal-like 1 and 2, mesenchymal and luminal androgen receptor) molecular sub-types has largely eluded researchers. The introduction of immunotherapy, currently useful only for patients with PD-L1 positive cancers, led to the stratification of first-line therapy using this immunohistochemical biomarker. Germline BRCA gene mutations can also be targeted with PARP inhibitors in both the adjuvant and metastatic settings. In contrast, the benefit of the anti-Trop-2 antibody-drug conjugate (ADC) Sacituzumab govitecan (SG) does not appear confined to patients with tumours expressing high levels of Trop-2, leading to its potential utility for any patient with an estrogen receptor (ER)-negative, HER2-negative advanced breast cancer (ABC). Most recently, low levels of HER2 expression, detected in up to 60% of TNBC, predicts benefit from the potent HER2-directed antibody-drug conjugate trastuzumab deruxtecan (T-DXd), defining an additional treatment option for this sub-group. Regrettably, despite recent advances, the median survival of TNBC continues to lag far behind the approximately 5 years now expected for patients with ER-positive or HER2-positive breast cancers. We review the data supporting immunotherapy, ADCs, and targeted agents in subgroups of patients with TNBC, and current clinical trials that may pave the way to further advances in this challenging disease.

Inflammation, Infiltration, and Evasion-Tumor Promotion in the Aging Breast

Breast cancer is a significant cause of morbidity and mortality in women, with over two million new cases reported worldwide each year, the majority of which occur in post-menopausal women. Despite advances in early detection and treatment, approximately one-third of patients diagnosed with breast cancer will develop metastatic disease. The pathogenesis and progression of breast cancer are influenced by a variety of biological and social risk factors, including age, ethnicity, pregnancy status, diet, and genomic alterations. Recent advancements in breast cancer research have focused on harnessing the power of the patient's adaptive and innate immune systems for diagnostic and therapeutic purposes. The breast immune microenvironment plays a critical role in regulating tissue homeostasis and resistance to tumorigenesis. In this review, we explore the dynamic changes in the breast immune microenvironment that occur with age, how these changes impact breast cancer development and progression, and how targeted therapeutic interventions that leverage the immune system can be used to improve patient outcomes. Our review emphasizes the importance of understanding the complex interplay between aging, the immune system, and breast cancer, and highlights the potential of immune-based therapies in the fight against this devastating disease.

PD-L1 immunohistochemistry assay optimization to provide more comprehensive pathological information in classic Hodgkin lymphoma

Overexpression of PD-L1 can be a predictive marker for anti-PD-1 therapeutic efficacy in classic Hodgkin lymphoma (CHL); however, harmonization of different IHC assays remains to be accomplished, and interpretations of PD-L1 immunostaining results remain controversial in CHL. In this study, we sought to optimize the PD-L1 immunohistochemistry (IHC) assay in CHL. All tests were performed on a tumour tissue microarray established from 54 CHL cases. Three IHC antibodies (405.9A11, SP142, 22C3) for detecting PD-L1 expression were compared semi quantitatively with the RNAscope assay (No. 310035, ACD), and the difference in the expression in background immune cells (ICs) between assays and the associations of expression levels with densities of TILs/TAMs were also analysed. 405.9A11 demonstrated best specificity in HRS cells and best sensitivity in ICs. Positive expression of PD-L1 was more frequent in ICs (85.2%) than in HRS cells (48.1%). Different subgroups of background ICs, including tumour-associated macrophages (TAMs), were assessed and scored for CD4, CD8, FOXP3, and CD163 expression. PD-L1 expression on ICs was the factor most associated with the density of TAMs. 405.9A11 provided the most convincing PD-L1 expression results. Pathologists should report PD-L1 expression in a combined manner, including both the status of HRS cells and the percentage of PD-L1-positive ICs.

Tissue- and liquid biopsy-based biomarkers for immunotherapy in breast cancer

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy and now represent the mainstay of treatment for many tumor types, including triple-negative breast cancer and two agnostic registrations. However, despite impressive durable responses suggestive of an even curative potential in some cases, most patients receiving ICIs do not derive a substantial benefit, highlighting the need for more precise patient selection and stratification. The identification of predictive biomarkers of response to ICIs may play a pivotal role in optimizing the therapeutic use of such compounds. In this Review, we describe the current landscape of tissue and blood biomarkers that could serve as predictive factors for ICI treatment in breast cancer. The integration of these biomarkers in a "holistic" perspective aimed at developing comprehensive panels of multiple predictive factors will be a major step forward towards precision immune-oncology.

Atezolizumab plus anthracycline-based chemotherapy in metastatic triple-negative breast cancer: the randomized, double-blind phase 2b ALICE trial

Immune checkpoint inhibitors have shown efficacy against metastatic triple-negative breast cancer (mTNBC) but only for PD-L1positive disease. The randomized, placebo-controlled ALICE trial ( NCT03164993 , 24 May 2017) evaluated the addition of atezolizumab (anti-PD-L1) to immune-stimulating chemotherapy in mTNBC. Patients received pegylated liposomal doxorubicin (PLD) and low-dose cyclophosphamide in combination with atezolizumab (atezo-chemo; n = 40) or placebo (placebo-chemo; n = 28). Primary endpoints were descriptive assessment of progression-free survival in the per-protocol population (>3 atezolizumab and >2 PLD doses; n = 59) and safety in the full analysis set (FAS; all patients starting therapy; n = 68). Adverse events leading to drug discontinuation occurred in 18% of patients in the atezo-chemo arm (7/40) and in 7% of patients in the placebo-chemo arm (2/28). Improvement in progression-free survival was indicated in the atezo-chemo arm in the per-protocol population (median 4.3 months versus 3.5 months; hazard ratio (HR) = 0.57; 95% confidence interval (CI) 0.33-0.99; log-rank P = 0.047) and in the FAS (HR = 0.56; 95% CI 0.33-0.95; P = 0.033). A numerical advantage was observed for both the PD-L1positive (n = 27; HR = 0.65; 95% CI 0.27-1.54) and PD-L1negative subgroups (n = 31; HR = 0.57, 95% CI 0.27-1.21). The progression-free proportion after 15 months was 14.7% (5/34; 95% CI 6.4-30.1%) in the atezo-chemo arm versus 0% in the placebo-chemo arm. The addition of atezolizumab to PLD/cyclophosphamide was tolerable with an indication of clinical benefit, and the findings warrant further investigation of PD1/PD-L1 blockers in combination with immunomodulatory chemotherapy.

Atezolizumab plus nab-paclitaxel for unresectable, locally advanced or metastatic breast cancer: real-world results from a single academic center in Austria

Purpose

IMpassion130 led to the approval of atezolizumab plus nab-paclitaxel as first-line treatment for patients with unresectable locally advanced or metastatic triple-negative, PD-L1 immune-cell positive breast cancer (BC) by the European Medicines Agency (EMA). The objective of the present study was to investigate the implementation, safety and efficacy of this combination in the initial phase after approval.

Methods

A retrospective data analysis including all BC patients who received atezolizumab and nab-paclitaxel between 1.1.2019 and 31.10.2020 at the Department of Obstetrics and Gynecology and the Department of Medicine 1, respectively, at the Medical University of Vienna, Austria, was performed. Progression-free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Maier product-limit method. Owing to the retrospective nature of this study, all statistics must be considered exploratory.

Results

In total 20 patients were included in the study. Median follow-up was 7.1 months (IQR 5.2–9.1). Median PFS was 3.0 months (SE = .24; 95% CI [2.5; 3.5]). Median OS was 8.94 months (SE = 2.34, 95%CI [4.35; 13.53]). No new safety signals were observed.

Conclusion

The present study showed a considerably shorter PFS (3.0 vs. 7.5 months) and OS (8.94 vs. 25.0 months) than IMpassion130 putatively owing to the use of atezolizumab in later treatment lines, more aggressive tumors and a study population with higher morbidity compared to the pivotal trial.

Concordance of PD-L1 expression in triple-negative breast cancers in Chinese patients: A retrospective and pathologist-based study

OBJECTIVE

To compare the expression of programmed cell death ligand 1 (PD-L1) in different paraffin blocks from the same triple-negative breast cancers (TNBC) specimen and between matched primary tumors and lymph node metastases (LNMets). We also aim to determine the interobserver agreement between pathologists trained on PD-L1 (SP142) assay in assessing TNBC.

METHODS

426 histologically confirmed TNBC cases, in which 85 have LNMets, were included in this study. A PD-L1 (SP142) assay was used to identify PD-L1 expression on tumor infiltrating immune cells (IC) and also on tumor cells (TC) in primary tumors and LNMets of TNBC by two trained pathologists. PD-L1 scoring and assessment were based on criteria in IMpassion 130 trial criteria. Concordance of PD-L1 expression in TNBC were analyzed using Kappa-test and assessed by the Kappa value.

RESULTS

Prevalence of positive PD-L1 expression (PD-L1 +) on tumor-infiltrating immune cells (PD-L1 IC+) (IC≥1%) in LNMets (49.4%) was higher than in the matched primary tumors (38.9%). Concordance of PD-L1 expression on IC between the two paraffin blocks from the same primary tumor specimen was substantial (P < 0.000, Kappa = 0.627) and was identified in 83.1% (108/130) of the selected cases. For TNBC cases with matched primary and LNMets blocks, the concordance of PD-L1IC scoring between the two blocks was moderate (P < 0.000, Kappa = 0.434). Interobserver agreement of PD-L1 assessment was 78.2% (P < 0.000, Kappa = 0.567) in primary tumors and 61.4% (P < 0.000, Kappa = 0.253) in the matched LNets.

CONCLUSION

Substantial intratumor concordance of PD-L1 scoring of the primary tumors in TNBC patients was determined, implying that immunohistochemically detection using one representative block of the primary tumor should be enough to assign the expression status of PD-L1 in clinical practice. The prevalence of PD-L1 + in lymph node metastases (LNMets) was higher than in the matched primary tumors, implying that PD-L1 detection in LNMets may provide additional PD-L1 expression information, especially in TNBC cases with PD-L1- in the matched primary breast tumors. Interobserver agreement of PD-L1 scoring in primary tumors was moderate while only fair in LNMets, implying that the additional training for PD-L1 assessment of TNBC LNMets specimens is recommended to enhance interobserver agreement.

DATA AVAILABILITY

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Significance of the effects of chemotherapy on programmed death-ligand 1 expression in triple-negative breast cancer

BACKGROUND

Atezolizumab has been approved as an antibody against programmed death-ligand 1 (PD-L1)-positive immune cells in patients with advanced or recurrent triple-negative breast cancer. However, the optimal timing to examine PD-L1 expression remains controversial. We retrospectively researched PD-L1 positivity rates in biopsy, surgical and recurrent specimens from patients with triple-negative breast cancer treated with neoadjuvant chemotherapy. We also examined alterations in PD-L1 and their meaning.

METHODS

In total, 35 triple-negative breast cancer biopsy specimens obtained before neoadjuvant chemotherapy, 20 corresponding specimens obtained after neoadjuvant chemotherapy and 5 corresponding recurrent specimens were obtained. We examined PD-L1 immunohistochemistry on tumor cells and tumor-infiltrating immune cells using SP142 antibody.

RESULTS

In comparison with specimens obtained before neoadjuvant chemotherapy, PD-L1 expression randomly changed in immune cells after neoadjuvant chemotherapy, but PD-L1 expression was significantly reduced in tumor cells. Pre-neoadjuvant chemotherapy specimens with low PD-L1 expression (PD-L1 scores of ≤1 for both immune cells and tumor cells) were linked to better disease-free survival (P < 0.001) and overall survival (P < 0.001) than the other specimens.

CONCLUSION

This is the first study to evaluate PD-L1 expression both before and after chemotherapy in breast cancer and examine its relationship with prognosis. The results suggest that the PD-L1 level may be useful for predicting the prognosis of patients with triple-negative breast cancer who do not have pathological complete responses to neoadjuvant chemotherapy.

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.

Immune-Based Therapy in Triple-Negative Breast Cancer: From Molecular Biology to Clinical Practice

Triple-negative breast cancer (TNBC) has been considered for many years an orphan disease in terms of therapeutic options, with conventional chemotherapy (CT) still representing the mainstay of treatment in the majority of patients. Although breast cancer (BC) has been historically considered a "cold tumor", exciting progress in the genomic field leading to the characterization of the molecular portrait and the immune profile of TNBC has opened the door to novel therapeutic strategies, including Immune Checkpoint Inhibitors (ICIs), Poly ADP-Ribose Polymerase (PARP) inhibitors and Antibody Drug Conjugates (ADCs). In particular, compared to standard CT, the immune-based approach has been demonstrated to improve progression-free survival (PFS) and overall survival (OS) in metastatic PD-L1-positive TNBC and the pathological complete response rate in the early setting, regardless of PD-L1 expression. To date, PD-L1 has been widely used as a predictor of the response to ICIs; however, many patients do not benefit from the addition of immunotherapy. Therefore, PD-L1 is not a reliable predictive biomarker of the response, and its accuracy remains controversial due to the lack of a consensus about the assay, the antibody, and the scoring system to adopt, as well as the spatial and temporal heterogeneity of the PD-L1 status. In the precision medicine era, there is an urgent need to identify more sensitive biomarkers in the BC immune oncology field other than just PD-L1 expression. Through the characterization of the tumor microenvironment (TME), the analysis of peripheral blood and the evaluation of immune gene signatures, novel potential biomarkers have been explored, such as the Tumor Mutational Burden (TMB), Microsatellite Instability/Mismatch Repair Deficiency (MSI/dMMR) status, genomic and epigenomic alterations and tumor-infiltrating lymphocytes (TILs). This review aims to summarize the recent knowledge on BC immunograms and on the biomarkers proposed to support ICI-based therapy in TNBC, as well as to provide an overview of the potential strategies to enhance the immune response in order to overcome the mechanisms of resistance.

Fatty acid synthetase expression in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) has a relatively poor prognosis. Research has identified potential metabolic targets, including fatty acid metabolism, in TNBC. The absence of effective target therapies for TNBC led to exploration of the role of fatty acid synthetase (FASN) as a potential target for TNBC therapy. Here, we analyzed the expression of FASN, a representative lipid metabolism–related protein, and investigated the association between FASN expression and Ki-67 and the programmed death ligand 1 (PD-L1) biomarkers in TNBC.

Methods

Immunohistochemical expression of FASN was analyzed in 166 patients with TNBC. For analytical purposes, patients with 0–1+ FASN staining were grouped as low-grade FASN and patients with 2–3+ FASN staining as high-grade FASN.

Results

FASN expression was observed in 47.1% of TNBC patients. Low and high expression of FASN was identified in 75.9% and 24.1%, respectively, and no statistically significant difference was found in T category, N category, American Joint Committee on Cancer stage, or recurrence rate between the low and high-FASN expression groups. Ki-67 proliferation level was significantly different between the low and high-FASN expression groups. FASN expression was significantly related to Ki-67 as the level increased. There was no significant difference in PD-L1 positivity between the low- and high-FASN expression groups.

Conclusions

We identified FASN expression in 166 TNBC patients. The Ki-67 proliferation index was positively correlated with FASN level, indicating higher proliferation activity as FASN increases. However, there was no statistical association with PD-L1 SP142, the currently FDA-approved assay, or FASN expression level.

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.

Treatment landscape of triple-negative breast cancer - expanded options, evolving needs

Tumour heterogeneity and a long-standing paucity of effective therapies other than chemotherapy have contributed to triple-negative breast cancer (TNBC) being the subtype with the least favourable outcomes. In the past few years, advances in omics technologies have shed light on the relevance of the TNBC microenvironment heterogeneity, unveiling a close dynamic relationship with cancer cell features. An improved understanding of tumour-immune system co-evolution supports the need to adopt a more comprehensive view of TNBC as an ecosystem that encompasses the intrinsic and extrinsic features of cancer cells. This new appreciation of the biology of TNBC has already led to the development of novel targeted agents, including PARP inhibitors, antibody-drug conjugates and immune-checkpoint inhibitors, which are revolutionizing the therapeutic landscape and providing new opportunities both for patients with early-stage TNBC and for those with advanced-stage disease. The current therapeutic scenario is only the tip of the iceberg, as hundreds of new compounds and combinations are in development. The translation of these experimental therapies into clinical benefit is a welcome and ongoing challenge. In this Review, we describe the current and upcoming therapeutic landscape of TNBC and discuss how an integrated view of the TNBC ecosystem can define different levels of risk and provide improved opportunities for tailoring treatment.

Interobserver Agreement of PD-L1/SP142 Immunohistochemistry and Tumor-Infiltrating Lymphocytes (TILs) in Distant Metastases of Triple-Negative Breast Cancer: A Proof-of-Concept Study. A Report on Behalf of the International Immuno-Oncology Biomarker Working Group

Patients with advanced triple-negative breast cancer (TNBC) benefit from treatment with atezolizumab, provided that the tumor contains ≥1% of PD-L1/SP142-positive immune cells. Numbers of tumor-infiltrating lymphocytes (TILs) vary strongly according to the anatomic localization of TNBC metastases. We investigated inter-pathologist agreement in the assessment of PD-L1/SP142 immunohistochemistry and TILs. Ten pathologists evaluated PD-L1/SP142 expression in a proficiency test comprising 28 primary TNBCs, as well as PD-L1/SP142 expression and levels of TILs in 49 distant TNBC metastases with various localizations. Interobserver agreement for PD-L1 status (positive vs. negative) was high in the proficiency test: the corresponding scores as percentages showed good agreement with the consensus diagnosis. In TNBC metastases, there was substantial variability in PD-L1 status at the individual patient level. For one in five patients, the chance of treatment was essentially random, with half of the pathologists designating them as positive and half negative. Assessment of PD-L1/SP142 and TILs as percentages in TNBC metastases showed poor and moderate agreement, respectively. Additional training for metastatic TNBC is required to enhance interobserver agreement. Such training, focusing on metastatic specimens, seems worthwhile, since the same pathologists obtained high percentages of concordance (ranging from 93% to 100%) on the PD-L1 status of primary TNBCs.

PD-L1 testing based on the SP142 antibody in metastatic triple-negative breast cancer: summary of an expert round-table discussion

Triple-negative breast cancer (TNBC) is more aggressive than other breast cancer subtypes. TNBC is characterized by increased expression of Programmed Death-ligand 1 (PD-L1), a signal used by many tumors to escape the immune response. Expression of PD-L1 is a positive predictor of response to immunotherapy; therefore, it should be investigated in TNBC in order to select patients who may benefit from anti-PD-L1 therapies. While many PD-L1 assays are available, only the VENTANA platform with the anti-PD-L1 (SP142) antibody is licensed as a companion diagnostic device for selecting patients with metastatic/advanced TNBC who are candidates for treatment with atezolizumab. In this article, we provide a summary of an expert round-table discussion about PD-L1 testing, using the SP142 antibody in metastatic TNBC.

Current status of PD-1/PD-L1 blockade immunotherapy in breast cancer

Over the past 10 years, immunotherapy with immune checkpoint inhibitors has revolutionized the management of various cancers. However, immunotherapy in breast cancer has not been successful. Breast cancer has long been recognized as an immunologically 'cold' tumor, although a higher frequency of tumor-infiltrating lymphocytes present in certain subtypes and an association between tumor-infiltrating lymphocytes and favorable prognosis have been reported. In March 2019, the combination of atezolizumab and nanoparticle albumin-bound paclitaxel was granted accelerated approval in the United States for the treatment of programmed death-ligand 1-positive advanced or metastatic triple-negative breast cancer. This finally opened the door for immune checkpoint blockade therapy for breast cancer. Several clinical trials have been conducted using different combinations of immune checkpoint inhibitors and chemotherapy or targeted agents in various treatment settings for metastatic breast cancer and early-stage breast cancer. In this review, we summarize recent advances in immune checkpoint blockade therapy and predictive biomarkers in breast cancer.

Cancer Immunotherapy Update: FDA-Approved Checkpoint Inhibitors and Companion Diagnostics

Immune checkpoint inhibitors (ICIs) are considered a new standard-of-care across many cancer indications. This review provides an update on ICIs approved by the Food and Drug Administration (FDA), with focus on monoclonal antibodies that target the programmed cell death 1 (PD-1) or its ligand, PD-1 ligand 1 (PD-L1), including information on their clinical indications and associated companion diagnostics. The information is further discussed with strategies for identifying predictive biomarkers to guide the clinical use of PD-1/PD-L1-targeted therapies.

Breast Cancer Brain Metastasis-Overview of Disease State, Treatment Options and Future Perspectives

Simple Summary

In this review, we present the latest information on the pathophysiology, diagnosis, and local and systemic treatment of brain metastases from breast cancer, with a focus on recent publications. Improving the local treatment and subtype-specific systemic therapies through advancements in basic and translational research will contribute to better clinical outcomes for patients with breast cancer brain metastasis.

Abstract

Breast cancer is the second most common origin of brain metastasis after lung cancer. Brain metastasis in breast cancer is commonly found in patients with advanced course disease and has a poor prognosis because the blood–brain barrier is thought to be a major obstacle to the delivery of many drugs in the central nervous system. Therefore, local treatments including surgery, stereotactic radiation therapy, and whole-brain radiation therapy are currently considered the gold standard treatments. Meanwhile, new targeted therapies based on subtype have recently been developed. Some drugs can exceed the blood–brain barrier and enter the central nervous system. New technology for early detection and personalized medicine for metastasis are warranted. In this review, we summarize the historical overview of treatment with a focus on local treatment, the latest drug treatment strategies, and future perspectives using novel therapeutic agents for breast cancer patients with brain metastasis, including ongoing clinical trials.