PD-L1 Expression In Breast Cancer Research Articles

Local High-Dose Radiotherapy Induces Systemic Immunomodulating Effects of Potential Therapeutic Relevance in Oligometastatic Breast Cancer.

Local irradiation of cancer through radiotherapy can induce spontaneous regression of non-directly irradiated lesions, suggesting the involvement of systemic antitumor immune responses. In oligometastatic breast cancer (BC) patients, the use of stereotactic body radiotherapy (SBRT) favors the local control of treated lesions and may contribute to break local tolerance and release tumor-associated antigens (TAAs), improving host antitumor immunity. We performed a detailed immunomonitoring of BC patients undergoing SBRT to verify its ability to “switch on” the anti-tumor immunity both systemically, in peripheral blood, and locally, employing in vitro BC models. Twenty-one BC patients with ≤6 metastases were treated with 3 daily doses of 10 Gy with SBRT. Blood samples for immune profiling were collected before and after treatment. One month after treatment a third of patients displayed the boosting or even the de novo appearance of polyfunctional CD4+ and CD8+ T cell responses against known BC TAAs (survivin, mammaglobin-A, HER2), through intracellular staining in flow cytometry. Half of patients showed increased numbers of activated natural killer (NK) cells, measured with multispectral flow cytometry, immediately after the first dose of SBRT. Interestingly, high levels of activated NK cells at diagnosis correlated with a longer progression-free survival. BC in vitro models, treated with the same SBRT modality, showed enhanced expression of MHC class-I and class-II, major histocompatibility complex class I-related chain A/B, and Fas molecules, and increased release of pro-inflammatory cytokines, such as IL-1β and TNF-α. Consistently, we noticed enhanced production of perforin by CD4+ T cells when patients’ lymphocytes were cultured in the presence of irradiated BC cell line, compared to untreated targets. Besides immunogenic effects, SBRT also enhanced the percentages of circulating regulatory T cells, and increased indoleamine 2,3 dioxygenase and PD-L1 expression in BC in vitro models. These results suggest that SBRT may boost host antitumor immune responses also in an advanced disease setting such as oligometastatic BC, by inducing immunomodulating effects both locally and systemically. However, the concomitant induction of immunosuppressive pathways suggests that a combination with immunotherapy could further enhance the in situ vaccination ability of radiotherapy, possibly further improving the curative potential of SBRT in this subset of patients.

Clinicopathological and prognostic significance of programmed death ligand-1 expression in breast cancer: a meta-analysis

BackgroundProgrammed cell death-ligand 1 (PD-L1) may be a useful molecule for targeted immunotherapy. Therefore, this meta-analysis aimed to investigate PD-L1 expression in breast cancer and its associations with clinicopathological factors and outcomes, which may help determine whether PD-L1 expression is a useful prognostic marker.MethodsThe Medline Ovid, Cochrane, PubMed, Google Scholar, and Web of Knowledge databases were searched for studies that evaluated the prognostic or clinicopathological significance of PD-L1 expression in patients with breast cancer, and reported at least one survival-related outcome.ResultsSix studies that included 7877 cases were selected for the analysis. Higher PD-L1 expression in all cells was related to higher histological grade and lymph node metastasis. Higher PD-L1 expression in tumor cell was related to larger tumor size, estrogen receptor negativity, progesterone receptor negativity, human epidermal growth factor type-2 positivity, and triple-negative breast cancer. PD-L1 positivity in all cells was associated with poorer disease-free survival, although it was not significantly associated with overall survival.ConclusionThe present meta-analysis revealed that cases of breast cancer with PD-L1 positivity in all cells exhibited higher histological grades, lymph node metastasis, and poorer disease-free survival. Therefore, positive expression of PD-L1 may be a useful prognostic marker in breast cancer.

Immunotherapy in Breast Cancer: the Emerging Role of PD-1 and PD-L1.

The purpose of the review is to summarize the data regarding PD-L1 expression in breast cancer and the results of first clinical trials with PD-1 or PD-L1 inhibitors in patients with metastatic breast cancer. PD-L1 expression is heterogeneous across primary breast cancers, and is generally associated with the presence of tumor-infiltrating lymphocytes and the presence of poor-prognosis features such as high grade, and aggressive molecular subtypes (triple-negative (TN), basal, HER2-enriched). Early phase clinical trials using PD-1 or PD-L1 inhibitors alone or in combination have shown objective tumor responses and durable long-term disease control, in heavily pre-treated patients, notably in the TN subtype. Blockade of PD-1 or PD-L1 shows impressive antitumor activity in some subsets of breast cancer patients. Many clinical trials are ongoing in the metastatic and neoadjuvant setting, alone and in combination with chemotherapy, targeted therapy, radiotherapy, and/or other immune therapy. The identification of biomarkers predictive for a clinical benefit is warranted.

Prognostic Role of Programmed Death Ligand-1 Expression in Breast Cancer: A Systematic Review and Meta-Analysis.

Cancer therapies that target the PD-1/PD-L1 pathway are in ongoing phase I/II clinical trials for several tumor types. However, the prognostic value of PD-L1 expression in breast cancer is unclear. We assessed the prognostic role of PD-L1 expression in breast cancer. We searched Medline/PubMed for eligible studies of the association between PD-L1 expression and patient survival in breast cancer published before 7 December 2015. The effect size was the hazard ratio (HR) with 95% confidence interval (CI) for overall survival (OS), recurrence-free survival (RFS) and metastasis-free survival (MFS). Odds ratios (OR) with 95% CIs were also extracted to evaluate associations between PD-L1 expression and patient clinicopathological features. We included five studies with 7,802 total patients in this meta-analysis. The pooled OR associated high PD-L1 expression with predictors of poor-prognosis: high tumor grade, negative ER status, negative PR status, positive HER2 status and lymphovascular invasion. High PD-L1 protein expression was associated with shorter OS (HR = 3.22, 95% CI: 1.86-5.59; P < 0.0001), shorter RFS (HR = 1.38, 95% CI: 1.03-1.86; P = 0.03) and shorter MFS (HR = 3.33, 95% CI: 2.30-4.82; P < 0.00001); whereas high PD-L1 mRNA expression was associated with longer OS (HR = 0.86, 95% CI: 0.75-1.00; P = 0.05) and longer RFS (HR = 0.57, 95% CI: 0.36-0.91; P = 0.02). The findings of these studies were significantly heterogeneous; the results should be interpreted cautiously. In breast cancer, high PD-L1 protein expression appears to be a negative prognostic factor, whereas high PD-L1 mRNA expression appears to be a favorable prognostic factor.

Abstract 3243: Neutrophil elastase regulates PD-L1 expression in breast cancer

Abstract Introduction: We have previously reported that breast cancer cells take up the inflammatory mediator neutrophil elastase (NE) from tumor-associated neutrophils (TANs). NE uptake leads to: 1) increased cleavage of cyclin E (CCNE) to its low molecular weight isoforms and generation of the CCNE-derived immunogenic epitope CCNE144-152, 2) cross-presentation of the NE-derived epitope PR1, and 3) increased human leukocyte antigen (HLA) class I expression. NE is therefore a link between innate and adaptive immune responses in breast cancer. The current study was undertaken to investigate the effects of NE uptake on PD-L1 expression as another mechanism impacting adaptive immune responses in breast cancer. Methods: The breast cancer cell line MDA-MB-231 was maintained in standard media or media supplemented with NE. The effect of NE on cell surface expression of PD-L1 was determined using flow cytometry. Total PD-L1 protein expression was determined using western blot analysis performed on whole cell lysates. NE was inhibited with either elafin or alpha-1-antitrypsin to assess the requirement of enzymatic activity for the observed effects. Transcriptional regulation of PD-L1 expression by NE was assessed by qPCR. To evaluate specific transcription factors (TFs) involved in PD-L1 regulation, nuclear protein was isolated and analyzed for the activity of 16 TFs using a commercial plate array. The impact of NE uptake on TFs identified on the array was confirmed by western blot analysis. The functional effects of changes in PD-L1 expression were evaluated using an annexin V assay to assess T-cell apoptosis. Results: Addition of NE to breast cancer cells resulted in a reduction in PD-L1 surface expression as determined by flow cytometry and in total PD-L1 expression as shown by western blot analysis. The effect was reversed after removal of the cells from NE-supplemented media. The addition of elafin to inhibit NE enzymatic activity led to increased NE uptake by MDA-MB-231 cells with no change in PD-L1 cell surface expression. Treatment with alpha-1-antitrypsin prevented NE uptake and also abrogated its effect on PD-L1 expression. Together, these results suggest that uptake of enzymatically active NE is required to decrease PD-L1 expression. qPCR showed a decrease in the PD-L1 transcript suggesting that the effect of NE on PD-L1 is transcriptionally regulated. NE treatment resulted in decreased expression of TFs known to be involved in PD-L1 regulation, including STAT1, STAT3, and JUN. NE-treated breast cancer cells induced less apoptosis of T-cells compared with untreated breast cancer cells. Conclusions: Uptake of enzymatically active NE by breast cancer results in decreased cell surface and total PD-L1 expression, an effect that is in part transcriptionally regulated. These findings suggest another mechanism whereby the innate inflammatory mediator NE may impact adaptive immune responses in breast cancer. Citation Format: Victor Gall, Anne V. Philips, Akhil Chawla, Na Qiao, Lisa S. St. John, Pariya Sukhumalchandra, Mao Zhang, Jeffrey J. Molldrem, Gheath Alatrash, Elizabeth A. Mittendorf. Neutrophil elastase regulates PD-L1 expression in breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3243.

PD-L1 expression and CD274 gene alteration in triple-negative breast cancer: implication for prognostic biomarker.

PurposeTo estimate the therapeutic potential of PD-L1 inhibition in breast cancer, we evaluated the prevalence and significance of PD-L1 protein expression with a validated antibody and CD274 gene alternation in a large cohort of triple negative breast cancer (TNBC) and correlated with clinicopathological data and patients overall survival.MethodsImmunohistochemistry and in situ mRNA hybridization was used to detect PD-L1 protein and mRNA expression in tumor tissues from 183 TNBC patients respectively. Fluorescence in situ hybridization analysis was performed on PD-L1 strong expression samples to assess copy number on chromosome 9p24.1 of CD274 gene.ResultsExpression of PD-L1 by immune cells was observed in 4.9 % of TNBC, while expression by tumor cells accounted for 8.7 %. There was a high concordance in PD-L1 protein expression and PDL1 mRNA expression. Samples with PD-L1 strong expression were found to have a CD274 gene copy number gain. PD-L1 expression was correlated with higher tumor grade, but was independent of menopausal status, lymph nodes metastasis, histological subtype and tumor size. In addition, we used precise stratification of PD-L1 expression on tumor or immune cells of certain breast cancer subtype and suggested that patients with PD-L1 expression in basal-like tumors by immune cells or with CD274 gene copy number gain had a longer disease-specific overall survival.ConclusionsOur findings may promote the more precise analysis of PD-L1 expression in breast cancer and aid the selection of patients who may benefit from immune therapy.

High PD-L1 expression was associated with poor prognosis in 870 Chinese patients with breast cancer.

To investigate the role of PD-L1 expression in tumor recurrence and metastasis in Chinese patients with breast cancer. Suitable tissue samples were available from 870 patients with breast cancer. Paraffin-embedded tumor sections were stained with PD-L1 antibody. The correlations between PD-L1 expression and clinical characteristics, ER/PR/HER2 status and survival parameters were analyzed. Kaplan-Meier and univariate Cox proportional hazards model analyses were used to compare the survival of patients with high PD-L1 expression and patients with no PD-L1 expression. The median follow-up time was 98 months(range, 17-265 months).The positive rate of PD-L1 expression in breast cancer was 21.7% (189/870). PD-L1 high expression was inversely associated with larger tumor size, higher tumor grade, more positive lymph node number, as well as negative ER and PR status. PD-L1 expression was particularly higher in TNBC compared with non-TNBC, although no statistical significance was observed. Nomogram logistic regression results based on clinical and pathological features showed that the following factors were more likely associated with high PD-L1 expression: patient age younger than 35 years, larger tumor size, lymphovascular invasion and advanced stage. Our data indicated that patients with high PD-L1 expression had poor DFS, DMFS and overall survival compared with those with no PD-L1 expression. Univariate Cox proportional hazards model analysis showed that PD-L1 was an independent prognostic factor for tumor prognosis. PD-L1 expression is an important indicator of unfavorable prognosis in breast cancer patients.

78P - Evaluation of PDL1 expression in breast cancer by immunohistochemistry

78P - Evaluation of PDL1 expression in breast cancer by immunohistochemistry

Prognostic and predictive value of PDL1 expression in breast cancer.

Expression of programmed cell death receptor ligand 1 (PDL1) has been scarcely studied in breast cancer. Recently PD1/PDL1-inhibitors have shown promising results in different carcinomas with correlation between PDL1 tumor expression and responses. We retrospectively analyzed PDL1 mRNA expression in 45 breast cancer cell lines and 5,454 breast cancers profiled using DNA microarrays. Compared to normal breast samples, PDL1 expression was upregulated in 20% of clinical samples and 38% of basal tumors. High expression was associated with poor-prognosis features (large tumor size, high grade, ER-negative, PR-negative, ERBB2-positive status, high proliferation, basal and ERBB2-enriched subtypes). PDL1 upregulation was associated with biological signs of strong cytotoxic local immune response. PDL1 upregulation was not associated with survival in the whole population, but was associated with better metastasis-free and overall specific survivals in basal tumors, independently of clinicopathological features. Pathological complete response after neoadjuvant chemotherapy was higher in case of PDL1 upregulation (50% versus 21%). In conclusion, PDL1 upregulation, more frequent in basal breast cancers, was associated with increased T-cell cytotoxic immune response. In this aggressive subtype, upregulation was associated with better survival and response to chemotherapy. Reactivation of dormant tumor-infiltrating lymphocytes by PDL1-inhibitors could represent promising strategy in PDL1-upregulated basal breast cancer.