Tumor infiltrating lymphocytes are prognostic in triple negative breast cancer and predictive for trastuzumab benefit in early breast cancer: results from the FinHER trial

PD-L1 Expression as a Predictive Biomarker in Cancer Immunotherapy

The resurgence of cancer immunotherapy stems from an improved understanding of the tumor microenvironment. The PD-1/PD-L1 axis is of particular interest, in light of promising data demonstrating a restoration of host immunity against tumors, with the prospect of durable remissions. Indeed, remarkable clinical responses have been seen in several different malignancies including, but not limited to, melanoma, lung, kidney, and bladder cancers. Even so, determining which patients derive benefit from PD-1/PD-L1-directed immunotherapy remains an important clinical question, particularly in light of the autoimmune toxicity of these agents. The use of PD-L1 (B7-H1) immunohistochemistry (IHC) as a predictive biomarker is confounded by multiple unresolved issues: variable detection antibodies, differing IHC cutoffs, tissue preparation, processing variability, primary versus metastatic biopsies, oncogenic versus induced PD-L1 expression, and staining of tumor versus immune cells. Emerging data suggest that patients whose tumors overexpress PD-L1 by IHC have improved clinical outcomes with anti-PD-1-directed therapy, but the presence of robust responses in some patients with low levels of expression of these markers complicates the issue of PD-L1 as an exclusionary predictive biomarker. An improved understanding of the host immune system and tumor microenvironment will better elucidate which patients derive benefit from these promising agents.

Tumour infiltrating lymphocytes (TILs) in breast cancer during pregnancy

BACKGROUND

Tumour infiltrating lymphocytes (TILs) is one of the most exciting breast cancer biomarkers, yet no data is available on its prevalence in tumours diagnosed during pregnancy.

METHODS

We evaluated the prevalence of TILs (stromal and intratumoural) in pregnant and non-pregnant young breast cancer patients.

RESULTS

11/116 (9.6%) of the non-pregnant and 2/86 (2.3%) pregnant patients had TILs ≥ 50% (p < 0.001) with highest prevalence observed in triple negative tumours (p = 0.01).

CONCLUSIONS

This is the first report on TILs in tumours diagnosed during pregnancy. The low prevalence could reflect the state of low host immunity associated with pregnancy.

APOBEC3B expression in breast cancer reflects cellular proliferation, while a deletion polymorphism is associated with immune activation

Genomic sequencing studies of breast and other cancers have identified patterns of mutations that have been attributed to the endogenous mutator activity of APOBEC3B (A3B), a member of the AID/APOBEC family of cytidine deaminases. A3B gene expression is increased in many cancers, but its upstream drivers remain undefined. Furthermore, there exists a common germ-line deletion polymorphism (A3B(del)), which has been associated with a paradoxical increase in breast cancer risk. To examine causes and consequences of A3B expression and its constitutive absence in breast cancer, we analyzed two large clinically annotated genomic datasets [The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC)]. We confirmed that A3B expression is associated with aggressive clinicopathologic characteristics and adverse outcomes and show that A3B expression is highly correlated with proliferative features (mitosis and cell cycle-related gene expression) in breast and 15 of 16 other solid tumor types. However, breast cancers arising in homozygous A3B(del) individuals with A3B absent did not differ in these features, indicating that A3B expression is a reflection rather than a direct cause of increased proliferation. Using gene set enrichment analysis (GSEA), we detected a pattern of immune activation in A3B(del) breast cancers, which seems to be related to hypermutation arising in A3B(del) carriers. Together, these results provide an explanation for A3B overexpression and its prognostic effect, giving context to additional study of this mutator as a cancer biomarker or putative drug target. In addition, although immune features of A3B(del) require additional study, these findings nominate the A3B(del) polymorphism as a potential predictor for cancer immunotherapy.

Anti-PD-1 therapy in melanoma

Immune-regulatory mechanisms are used by cancer to hide from the immune system. Advances and in-depth understanding of the biology of melanoma and its interaction with the immune system have led to the development of some of antagonistic antibodies to the programmed death 1 pathway (PD-1) and one of its ligands, programmed death ligand 1 (PD-L1), which are demonstrating high clinical benefit rates and tolerability. Blocking the immune-regulatory checkpoints that limit T-cell responses to melanoma upon PD-1/PD-L1 modulation has provided clinically validated targets for cancer immunotherapy. Combinations with other anti-melanoma agents may result in additional benefits. Nivolumab, pembrolizumab (formerly known as MK-3475 and lambrolizumab), and pidilizumab are anti-PD-1 antibodies in clinical development for melanoma, non-small cell lung cancer, renal cell carcinoma, head and neck cancers, lymphoma, and several other cancers. Long-term survivors already have been reported with these therapies. In this review, we discuss the current state of anti-PD-1 agents, the evidence in the literature to support the combination of anti-PD-1 antibodies with other anti-cancer agents and discuss the future directions for rational design of clinical trials that keep on increasing the number of long-term survivors.

The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014

BACKGROUND

The morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) is gaining momentum as evidence strengthens for the clinical relevance of this immunological biomarker. Accumulating evidence suggests that the extent of lymphocytic infiltration in tumor tissue can be assessed as a major parameter by evaluation of hematoxylin and eosin (H&E)-stained tumor sections. TILs have been shown to provide prognostic and potentially predictive value, particularly in triple-negative and human epidermal growth factor receptor 2-overexpressing BC.

DESIGN

A standardized methodology for evaluating TILs is now needed as a prerequisite for integrating this parameter in standard histopathological practice, in a research setting as well as in clinical trials. This article reviews current data on the clinical validity and utility of TILs in BC in an effort to foster better knowledge and insight in this rapidly evolving field, and to develop a standardized methodology for visual assessment on H&E sections, acknowledging the future potential of molecular/multiplexed approaches.

CONCLUSIONS

The methodology provided is sufficiently detailed to offer a uniformly applied, pragmatic starting point and improve consistency and reproducibility in the measurement of TILs for future studies.

Genomic analysis reveals that immune function genes are strongly linked to clinical outcome in the North Central Cancer Treatment Group n9831 Adjuvant Trastuzumab Trial

PURPOSE

To develop a genomic signature that predicts benefit from trastuzumab in human epidermal growth factor receptor 2-positive breast cancer.

PATIENTS AND METHODS

DASL technology was used to quantify mRNA in samples from 1,282 patients enrolled onto the Combination Chemotherapy With or Without Trastuzumab in Treating Women With Breast Cancer (North Central Cancer Treatment Group N9831 [NCCTG-N9831]) adjuvant trastuzumab trial. Cox proportional hazard ratios (HRs), adjusted for significant clinicopathologic risk factors, were used to determine the association of each gene with relapse-free survival (RFS) for 433 patients who received chemotherapy alone (arm A) and 849 patients who received chemotherapy plus trastuzumab (arms B and C). Network and pathway analyses were used to identify key biologic processes linked to RFS. The signature was built by using a voting scheme.

RESULTS

Network and functional ontology analyses suggested that increased RFS was linked to a subset of immune function genes. A voting scheme model was used to define immune gene enrichment based on the expression of any nine or more of 14 immune function genes at or above the 0.40 quantile for the population. This model was used to identify immune gene-enriched tumors in arm A and arms B and C. Immune gene enrichment was linked to increased RFS in arms B and C (HR, 0.35; 95% CI, 0.22 to 0.55; P < .001), whereas arm B and C patients who did not exhibit immune gene enrichment did not benefit from trastuzumab (HR, 0.89; 95% CI, 0.62 to 1.28; P = .53). Enriched immune function gene expression as defined by our predictive signature was not associated with increased RFS in arm A (HR, 0.90; 95% CI, 0.60 to 1.37; P = .64).

CONCLUSION

Increased expression of a subset of immune function genes may provide a means of predicting benefit from adjuvant trastuzumab.

Building immunity to cancer with radiation therapy

Over the last decade there has been a dramatic shift in the focus of cancer research toward understanding how the body's immune defenses can be harnessed to promote the effectiveness of cytotoxic anti-cancer therapies. The ability of ionizing radiation to elicit anti-cancer immune responses capable of controlling tumor growth has led to the emergence of promising combination-based radio-immunotherapeutic strategies for the treatment of cancer. Herein we review the immunoadjuvant properties of localized radiation therapy and discuss how technological advances in radio-oncology and developments in the field of tumor-immunotherapy have started to revolutionize the therapeutic application of radiotherapy.

Tumor-infiltrating lymphocytes and response to neoadjuvant chemotherapy with or without carboplatin in human epidermal growth factor receptor 2-positive and triple-negative primary breast cancers

PURPOSE

Modulation of immunologic interactions in cancer tissue is a promising therapeutic strategy. To investigate the immunogenicity of human epidermal growth factor receptor 2 (HER2) -positive and triple-negative (TN) breast cancers (BCs), we evaluated tumor-infiltrating lymphocytes (TILs) and immunologically relevant genes in the neoadjuvant GeparSixto trial.

PATIENTS AND METHODS

GeparSixto investigated the effect of adding carboplatin (Cb) to an anthracycline-plus-taxane combination (PM) on pathologic complete response (pCR). A total of 580 tumors were evaluated before random assignment for stromal TILs and lymphocyte-predominant BC (LPBC). mRNA expression of immune-activating (CXCL9, CCL5, CD8A, CD80, CXCL13, IGKC, CD21) as well as immunosuppressive factors (IDO1, PD-1, PD-L1, CTLA4, FOXP3) was measured in 481 tumors.

RESULTS

Increased levels of stromal TILs predicted pCR in univariable (P < .001) and multivariable analyses (P < .001). pCR rate was 59.9% in LPBC and 33.8% for non-LPBC (P < .001). pCR rates ≥ 75% were observed in patients with LPBC tumors treated with PMCb, with a significant test for interaction with therapy in the complete (P = .002) and HER2-positive (P = .006), but not the TNBC, cohorts. Hierarchic clustering of mRNA markers revealed three immune subtypes with different pCR rates (P < .001). All 12 immune mRNA markers were predictive for increased pCR. The highest odds ratios (ORs) were observed for PD-L1 (OR, 1.57; 95% CI, 1.34 to 1.86; P < .001) and CCL5 (OR, 1.41; 95% CI, 1.23 to 1.62; P < .001).

CONCLUSION

Immunologic factors were highly significant predictors of therapy response in the GeparSixto trial, particularly in patients treated with Cb. After further standardization, they could be included in histopathologic assessment of BC.

The value of tumor infiltrating lymphocytes (TILs) for predicting response to neoadjuvant chemotherapy in breast cancer: a systematic review and meta-analysis

Background

We carried out a systematic review and meta-analysis to evaluate the predictive roles of tumor infiltrating lymphocytes (TILs) in response to neoadjuvant chemotherapy (NAC) in breast cancer.

Method

A PubMed and Web of Science literature search was designed. Random or fixed effect models were adopted to estimate the summary odds ratio (OR). Heterogeneity and sensitivity analyses were performed to explore heterogeneity among studies and to assess the effects of study quality. Publication bias was evaluated using a funnel plot, Egger's test and Begg's test. We included studies where the predictive significance of TILs, and/or TILs subset on the pathologic complete response (pCR) were determined in NAC of breast cancer.

Results

A total of 13 published studies (including 3251 patients) were eligible. In pooled analysis, the detection of higher TILs numbers in pre-treatment biopsy was correlated with better pCR to NAC (OR = 3.93, 95% CI, 3.26–4.73). Moreover, TILs predicted higher pCR rates in triple negative (OR = 2.49, 95% CI: 1.61–3.83), HER2 positive (OR = 5.05, 95% CI: 2.86–8.92) breast cancer, but not in estrogen receptor (ER) positive (OR = 6.21, 95%CI: 0.86–45.15) patients. In multivariate analysis, TILs were still an independent marker for high pCR rate (OR = 1.41, 95% CI: 1.19–1.66). For TILs subset, higher levels of CD8+ and FOXP3+ T-lymphocytes in pre-treatment biopsy respectively predicted better pathological response to NAC (OR = 6.44, 95% CI: 2.52–16.46; OR = 2.94, 95% CI: 1.05–8.26). Only FOXP3+ lymphocytes in post-NAC breast tissue were a predictive marker for low pCR rate in univariate (OR = 0.41, 95% CI: 0.21–0.80) and multivariate (OR = 0.36, 95% CI: 0.13–0.95) analysis.

Conclusion

Higher TILs levels in pre-treatment biopsy indicated higher pCR rates for NAC. TILs subset played different roles in predicting response to NAC.

Histological Analysis of γδ T Lymphocytes Infiltrating Human Triple-Negative Breast Carcinomas

Breast cancer is the leading cause of cancer death in women and the second most common cancer worldwide after lung cancer. The remarkable heterogeneity of breast cancers influences numerous diagnostic, therapeutic, and prognostic factors. Triple-negative breast carcinomas (TNBCs) lack expression of HER2 and the estrogen and progesterone receptors and often contain lymphocytic infiltrates. Most of TNBCs are invasive ductal carcinomas (IDCs) with poor prognosis, whereas prognostically more favorable subtypes such as medullary breast carcinomas (MBCs) are somewhat less frequent. Infiltrating T-cells have been associated with an improved clinical outcome in TNBCs. The prognostic role of γδ T-cells within CD3⁺ tumor-infiltrating T lymphocytes remains unclear. We analyzed 26 TNBCs, 14 IDCs, and 12 MBCs, using immunohistochemistry for the quantity and patterns of γδ T-cell infiltrates within the tumor microenvironment. In both types of TNBCs, we found higher numbers of γδ T-cells in comparison with normal breast tissues and fibroadenomas. The numbers of infiltrating γδ T-cells were higher in MBCs than in IDCs. γδ T-cells in MBCs were frequently located in direct contact with tumor cells, within the tumor and at its invasive border. In contrast, most γδ T-cells in IDCs were found in clusters within the tumor stroma. These findings could be associated with the fact that the patient’s prognosis in MBCs is better than that in IDCs. Further studies to characterize these γδ T-cells at the molecular and functional level are in progress.

Pathological non-response to chemotherapy in a neoadjuvant setting of breast cancer: an inter-institutional study

To identify markers of non-response to neoadjuvant chemotherapy (NAC) that could be used in the adjuvant setting. Sixteen pathologists of the European Working Group for Breast Screening Pathology reviewed the core biopsies of breast cancers treated with NAC and recorded the clinico-pathological findings (histological type and grade; estrogen, progesterone receptors, and HER2 status; Ki67; mitotic count; tumor-infiltrating lymphocytes; necrosis) and data regarding the pathological response in corresponding surgical resection specimens. Analyses were carried out in a cohort of 490 cases by comparing the groups of patients showing pathological complete response (pCR) and partial response (pPR) with the group of non-responders (pathological non-response: pNR). Among other parameters, the lobular histotype and the absence of inflammation were significantly more common in pNR (p < 0.001). By ROC curve analyses, cut-off values of 9 mitosis/2 mm(2) and 18% of Ki67-positive cells best discriminated the pNR and pCR + pPR categories (p = 0.018 and < 0.001, respectively). By multivariable analysis, only the cut-off value of 9 mitosis discriminated the different response categories (p = 0.036) in the entire cohort. In the Luminal B/HER2- subgroup, a mitotic count <9, although not statistically significant, showed an OR of 2.7 of pNR. A lobular histotype and the absence of inflammation were independent predictors of pNR (p = 0.024 and <0.001, respectively). Classical morphological parameters, such as lobular histotype and inflammation, confirmed their predictive value in response to NAC, particularly in the Luminal B/HER2- subgroup, which is a challenging breast cancer subtype from a therapeutic point of view. Mitotic count could represent an additional marker but has a poor positive predictive value.

The prognostic value of tumor-infiltrating lymphocytes in triple-negative breast cancer: a meta-analysis

In a recent meta-analysis, we demonstrated that rich tumor-infiltrating lymphocytes (TILs) were significantly correlated to a favorable breast cancer (BC) outcome largely in estrogen receptor-negative tumors. It is known that TILs predominate in triple-negative (TN) BC, and to the best of our knowledge, there is no published meta-analysis that examined their prognostic value exclusively in that subtype. Therefore, we planned this meta-analysis to explore the clinical utility of rich TILs in TN-BC. According to predefined selection criteria, literature search identified eight eligible studies. The meta-analysis included data on 2,987 patients with early stage BC. The median percentage of lymph node positivity was 47% (95% confidence interval [CI] 23-82%). Over a median follow-up of 113 months (95% CI 80-144 months), it was found that rich TILs were associated with 30% (hazard ratio [HR] = 0.70; 95% CI 0.56-0.87; P = 0.001), 22% (HR = 0.78; 95% CI 0.68-0.90; P = 0.0008), and 34% (HR = 0.66; 95% CI 0.53-0.83; P = 0.0003), reduction in the risk of recurrence, distant recurrence, and death, respectively. In addition, for every 10% increments in rich TILs, there was an approximate 15-20% reduction in any recurrence, distant recurrence, or mortality. Moreover, rich TILs predicted superior overall survival (OS) benefit irrespective of the disease phenotype (TN-BC or core-basal phenotype), TILs location (intratumoral or stromal), or TILs qualification as either TILs-non-specified, cytotoxic (CD8+) or regulatory (forkhead box protein 3, FOXP3+) T cells. Data on 5-negative phenotype population were limited, and rich TILs failed to demonstrate a prognostic significance in this phenotype. To investigate the heterogeneity that was shown in the analyses of disease-free survival and OS, a set of meta-analyses showed that the method used in TILs detection (hematoxylin and eosin stains vs. immunohistochemistry) could explain most of the variability in the pooled estimates. Rich TILs were significantly associated with better survival outcome in early TN-BC and should be considered as a strong prognostic factor in this subtype. The results from the current meta-analysis support integrating immunotherapy with conventional therapy in future BC research.

New strategies in breast cancer: the significance of molecular subtypes in systemic adjuvant treatment for small T1a,bN0M0 tumors

Awareness of breast cancer heterogeneity has strikingly increased in the past decade in parallel with the development of high-throughput molecular tests. Beyond the clear usefulness of antiestrogen treatment in luminal tumors and trastuzumab in HER2-positive tumors, breast cancer subtypes may have additional clinical and predictive roles that can be relevant to clinical practice. In this article, we discuss the significance of molecular subtypes in the systemic treatment of early-stage breast tumors smaller than 1 cm (T1a,bN0M0) and suggest new strategies for future treatment recommendations for these patients.

The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014

BACKGROUND

The morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) is gaining momentum as evidence strengthens for the clinical relevance of this immunological biomarker. Accumulating evidence suggests that the extent of lymphocytic infiltration in tumor tissue can be assessed as a major parameter by evaluation of hematoxylin and eosin (H&E)-stained tumor sections. TILs have been shown to provide prognostic and potentially predictive value, particularly in triple-negative and human epidermal growth factor receptor 2-overexpressing BC.

DESIGN

A standardized methodology for evaluating TILs is now needed as a prerequisite for integrating this parameter in standard histopathological practice, in a research setting as well as in clinical trials. This article reviews current data on the clinical validity and utility of TILs in BC in an effort to foster better knowledge and insight in this rapidly evolving field, and to develop a standardized methodology for visual assessment on H&E sections, acknowledging the future potential of molecular/multiplexed approaches.

CONCLUSIONS

The methodology provided is sufficiently detailed to offer a uniformly applied, pragmatic starting point and improve consistency and reproducibility in the measurement of TILs for future studies.

Strategies to overcome trastuzumab resistance in HER2-overexpressing breast cancers: focus on new data from clinical trials

Breast cancers over-express the human epidermal growth factor receptor 2 (HER2) in about 15% of patients. This transmembrane tyrosine kinase receptor activates downstream signaling pathways and leads to proliferation of cancer cells. Trastuzumab, an anti-HER2 monoclonal antibody, improves outcome in women with early and metastatic breast cancer. Resistance to trastuzumab involves the phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway, truncation of the Her2 receptor or lack of immune response. The last decade has seen major advances in strategies to overcome resistance to trastuzumab. This includes the development of antibody-drug conjugates, dual HER2 inhibition strategies, inhibition of PI3K/mTOR pathway and development of modulators of immune checkpoints.

Association between CD8+ T-cell infiltration and breast cancer survival in 12,439 patients

BACKGROUND

T-cell infiltration in estrogen receptor (ER)-negative breast tumours has been associated with longer survival. To investigate this association and the potential of tumour T-cell infiltration as a prognostic and predictive marker, we have conducted the largest study of T cells in breast cancer to date.

PATIENTS AND METHODS

Four studies totalling 12 439 patients were used for this work. Cytotoxic (CD8+) and regulatory (forkhead box protein 3, FOXP3+) T cells were quantified using immunohistochemistry (IHC). IHC for CD8 was conducted using available material from all four studies (8978 samples) and for FOXP3 from three studies (5239 samples)-multiple imputation was used to resolve missing data from the remaining patients. Cox regression was used to test for associations with breast cancer-specific survival.

RESULTS

In ER-negative tumours [triple-negative breast cancer and human epidermal growth factor receptor 2 (human epidermal growth factor receptor 2 (HER2) positive)], presence of CD8+ T cells within the tumour was associated with a 28% [95% confidence interval (CI) 16% to 38%] reduction in the hazard of breast cancer-specific mortality, and CD8+ T cells within the stroma with a 21% (95% CI 7% to 33%) reduction in hazard. In ER-positive HER2-positive tumours, CD8+ T cells within the tumour were associated with a 27% (95% CI 4% to 44%) reduction in hazard. In ER-negative disease, there was evidence for greater benefit from anthracyclines in the National Epirubicin Adjuvant Trial in patients with CD8+ tumours [hazard ratio (HR) = 0.54; 95% CI 0.37-0.79] versus CD8-negative tumours (HR = 0.87; 95% CI 0.55-1.38). The difference in effect between these subgroups was significant when limited to cases with complete data (P heterogeneity = 0.04) and approached significance in imputed data (P heterogeneity = 0.1).

CONCLUSIONS

The presence of CD8+ T cells in breast cancer is associated with a significant reduction in the relative risk of death from disease in both the ER-negative [supplementary Figure S1, available at Annals of Oncology online] and the ER-positive HER2-positive subtypes. Tumour lymphocytic infiltration may improve risk stratification in breast cancer patients classified into these subtypes. NEAT ClinicalTrials.gov: NCT00003577.

Personalized treatments of cancer patients: a reality in daily practice, a costly dream or a shared vision of the future from the oncology community?

Therapies targeting activated oncogenes have been associated with several successes in the last decades that are described in this review, together with their limits and related unsolved questions. Most of the tumours will eventually develop drug resistance potentially due to intratumor heterogeneity and selection of additional molecular events. Moreover, studies in the field of molecular characterisation of cancers have shown that most tumors include large number of rare genomic events. Developing new drugs requires the use of large-scale molecular screening programs to enrich phase I/II trials with patients presenting the genetic alterations to treat them with the appropriate drug(s). Administering one single drug will incur in non-durable results, so the future is to cleverly combine drugs. Development of personalized immunotherapeutics and/or anti-angiogenic agents could change the natural history of several cancers. Finally, other systems including DNA repair and metabolism have become targetable. These considerations justify the development of molecular medicine with the characterisation of each tumour to assess defects in all the systems previously mentioned to propose a unique combination of therapies to each patient. Current drug development is clearly not appropriate, and studies with drugs given in relevant combinations should be favoured by new relationships between academia and industry. New organisational and medico-economics approaches are required to minimize the financial burden of personalized medicine by considering the foreseen decrease of the costs of new technologies, and the money saved by avoiding the use of many costly, useless but nonetheless toxic treatments given after failure of standard therapy.

PD-L1 expression and tumor-infiltrating lymphocytes: Revisiting the antitumor immune response potential in breast cancer

Upon analysis of 636 primary breast carcinoma patient samples, we have found that programmed cell death ligand 1 (PD-L1) mRNA expression is associated with tumor-infiltrating lymphocytes (TILs). Furthermore, PD-L1 expression and elevated TILs were associated with longer recurrence-free survival. Thus, our findings indicate that PD-L1 is prognostic in breast cancer and suggests a functional link between TILs and tumor PD-L1 upregulation.