Tumor-infiltrating lymphocytes in breast cancer: A new predictor for responses to therapy

T-cell immune checkpoint inhibition plus hypomethylation for locally advanced HER2-negative breast cancer: a phase 2 neoadjuvant window trial of decitabine and pembrolizumab followed by standard neoadjuvant chemotherapy

BACKGROUND

Higher levels of tumor-infiltrating lymphocytes (TILs) in breast cancers are associated with increased likelihood of pathologic complete response (pCR) to chemotherapy. DNA methyltransferase inhibitors (DNMTi) can augment immune responses to cancers, decreasing myeloid-derived suppressor cells (MDSCs) and increasing T lymphocyte responsiveness. We have shown that the DNMTi decitabine augments the effectiveness of immunotherapy using murine triple-negative breast cancer (TNBC) models. The primary objective was to determine whether DNMTi+immune checkpoint blockade would increase stromal TIL (sTIL) in primary breast cancers before neoadjuvant chemotherapy (NCT).

METHODS

In a phase 2 study (NCT02957968), patients with human epidermal growth factor receptor 2-negative breast cancer received window immunotherapy-decitabine (15 mg/m2×4 doses over 5 days) followed by 2 doses of pembrolizumab (200 mg, 2 weeks apart)-before starting NCT. Biopsies before and after window immunotherapy quantified TILs and programmed death-ligand 1 (PD-L1) expression. Patients proceeded to NCT and tumor resection per standard of care. Mid-study, results of the KEYNOTE 522 trial led to patients with TNBC receiving additional pembrolizumab concurrently with standard NCT and in the adjuvant setting.

RESULTS

46 patients (median age 54.5 years, range 28-72; 71.7% white, 28.3% black; 100% female) were treated. 21 patients had TNBC and received neither neoadjuvant pembrolizumab concurrently with NCT nor adjuvant pembrolizumab (Cohort A), 7 patients had TNBC and did receive concurrent and/or adjuvant pembrolizumab (Cohort A2), and 18 patients were estrogen receptor positive and/or progesterone receptor positive and received neither concurrent nor adjuvant pembrolizumab (Cohort B). Blood samples collected after decitabine administration before pembrolizumab showed a 59% decrease (p<0.01) in monocytic MDSCs compared with baseline. 38 patients had paired biopsies for sTIL and 37 for PD-L1 evaluation. Cohorts A/A2 experienced an sTIL increase of 6.1% (p<0.008); Cohort B experienced an sTIL increase of 8.3% (p=0.006). PD-L1 expression increased by 73.9% (p<0.01). 14 of 43 patients (32.6%) who proceeded to resection achieved pCR (n=11 of 27 (40.1%) in Cohorts A/A2 and n=3 of 16 (18.8%) in Cohort B). The most frequently reported immune-related adverse events were adrenal insufficiency (AI) (n=6, 13.0%), maculopapular rash (n=3, 6.5%), and hypothyroidism (n=3, 6.5%). Five of the six AI instances were at least partially attributable to hypophysitis/pituitary dysfunction, and one remains uncertain.

CONCLUSIONS

Treatment in the pre-neoadjuvant window with decitabine and pembrolizumab could sensitize breast cancers to standard NCT by recruitment of TILs to the tumor tissue. The treatment was well-tolerated.

TRIAL REGISTRATION NUMBER

NCT02957968.

Association of tumor-infiltrating lymphocytes with recurrence score in hormone receptor-positive/HER2-negative breast cancer: Analysis of four prospective studies

BACKGROUND

The clinical value of tumor infiltrating lymphocytes (TILs) in hormone receptor-positive (HR+)/HER2- breast cancer (BC) may be unearthed by focusing on more biologically aggressive tumors. Here we deepen and describe the correlation between RS and TILs, proposing an immuno-genomic model for HR+ /HER2- BC.

METHODS

We enrolled T1-T3, N0-N1 BC patients with available RS® and TILs in the context of four multicenter, prospective studies. RS® and TILs were considered as continuous and categorical variables. RS® was categorized into: 0-10 (low risk), 11-25 (intermediate risk) and 26-100 (high risk); TILs were categorized into: low TILs (0-10%), intermediate TILs (11-59%) and high TILs (60-100%).

RESULTS

811 patients were included. RS distribution was (n = 810): low risk 22.0%, intermediate risk 61.2%, high risk 16.8%. TIL distribution was (n = 455): low TILs 84.6%, intermediate TILs 13.6% and high TILs 1.8%. A significant, weak positive, linear correlation was found between continuous TILs and RS (Pearson coefficient=0.223, p < 0.001). When considering RS and TILs categories, tumors with intermediate/high TIL levels significantly enriched the high RS subgroup (p = 0.006). This was confirmed both within Luminal A and Luminal B cohorts. Among high-RS patients, 16.7% of Luminal A and 26.7% of Luminal B tumors had intermediate/high TILs.

CONCLUSIONS

We observed that RS® and TILs capture only slightly overlapping information on the biology of HR+ /HER2- tumor microenvironment. We demonstrated the feasibility of combining RS and TILs into a composite immuno-genomic model, which may serve the purpose of guiding and focalizing patient selection in the further development of immunotherapy strategies for Luminal-like disease.

Role of cytotoxic T cells and PD-1 immune checkpoint pathway in papillary thyroid carcinoma

Background

Lymphocytic thyroiditis (LT) is frequently seen in the tumor microenvironment (TME) of papillary thyroid carcinomas (PTCs). However, the characteristic of these tumor-infiltrating lymphocytes (TILs) is not well understood.

Objective

We aim to define the TME of PTC cases by characterizing the TILs.

Design

This is a cross-sectional observational study.

Patients

We enrolled 29 PTC (23 having concurrent LT), 14 LT, and 13 hyperplastic nodules with LT (HN) patients from January 2016 to December 2020.

Measurements

Immunohistochemical (IHC) expression of CD8, FoxP3, PD-1, and PD-L1 was studied in PTC with LT and compared with HN. PD-1 and PD-L1 expression was correlated at the mRNA level by quantitative real-time PCR. Immunophenotyping of TILs was done in FNAC samples of PTC and LT by flow cytometry.

Results

IHC revealed the presence of CD8+ cytotoxic T lymphocytes (CTLs) and FoxP3+ T regulatory cells (Tregs) in 83% and 52% of PTC with LT cases, respectively. Flow cytometric analysis of the PTC samples revealed a significant abundance of CTL compared with Treg and a higher CTL with lower Treg counts compared with LT. On IHC, PD-1 positivity was noted in 56.5% of PTC with LT cases, while intermediate PD-L1 positivity was found in 70% of the cases. There was a significant upregulation of PD-1 mRNA in PTC with LT. A significant correlation was noted with PD-L1 expression with lymph node metastasis and presence of Treg cells.

Conclusions

Increased expression of PD-1 and PD-L1 in the TME of PTC may provide a potential molecular mechanism for tumor survival despite the predominance of CTLs, possibly through their inactivation or exhaustion.

The types of tumor infiltrating lymphocytes are valuable for the diagnosis and prognosis of breast cancer

This study aimed at constructing a diagnostic immune risk score (dIRS) system and a prognostic immune risk score (pIRS) system for diagnose and prognosis of breast cancer (BC). The gene expression data of BC were downloaded from TCGA dataset (training set), and from GSE65194, GSE29044, GSE42568, and GSE20685 (validation sets). Then, the immune cell type proportions in each dataset were assessed using EPIC tool, and the dIRS system was built based on the SVM-RFE and RF-VIMP algorithms. Subsequently, the pIRS system and the nomogram survival model were established separately using penalized and rms packages. Finally, the differential expressed genes (DEGs) between low and high pIRS groups were screened, and submitted for functional analysis. The dIRS system consisted of B cells, CD8 + T cells, endothelial cells, NK cells, and other cells had high accuracy in distinguishing BC patients from the healthy controls (AUROC &gt;0.7). Subsequently, the pIRS system with the five prognosis-associated immune-infiltrating cell was constructed, and Kaplan-Meier analysis demonstrated that the survival rate of low pIRS group was significantly higher than that of high pIRS group (p &lt; 0.05). Based on age, pathologic stage and the pIRS values, the nomogram survival model was built. The AUROC value, Specificity value, Sensitivity value and C-index of the nomogram survival model were higher than 0.7000, and had a good predictive ability for BC. Finally, a total of 539 DEGs were identified, and significantly enriched in six pathways. The dIRS system and the pIRS system composed of immune cells might be critical for the diagnosis and prognosis of BC patients.

Immunostimulatory Properties of Chemotherapy in Breast Cancer: From Immunogenic Modulation Mechanisms to Clinical Practice

Breast cancer (BC) is the most common malignancy among females. Chemotherapy drugs remain the cornerstone of treatment of BC and undergo significant shifts over the past 100 years. The advent of immunotherapy presents promising opportunities and constitutes a significant complementary to existing therapeutic strategies for BC. Chemotherapy as a cytotoxic treatment that targets proliferation malignant cells has recently been shown as an effective immune-stimulus in multiple ways. Chemotherapeutic drugs can cause the release of damage-associated molecular patterns (DAMPs) from dying tumor cells, which result in long-lasting antitumor immunity by the key process of immunogenic cell death (ICD). Furthermore, Off-target effects of chemotherapy on immune cell subsets mainly involve activation of immune effector cells including natural killer (NK) cells, dendritic cells (DCs), and cytotoxic T cells, and depletion of immunosuppressive cells including Treg cells, M2 macrophages and myeloid-derived suppressor cells (MDSCs). Current mini-review summarized recent large clinical trials regarding the combination of chemotherapy and immunotherapy in BC and addressed the molecular mechanisms of immunostimulatory properties of chemotherapy in BC. The purpose of our work was to explore the immune-stimulating effects of chemotherapy at the molecular level based on the evidence from clinical trials, which might be a rationale for combinations of chemotherapy and immunotherapy in BC.

Increased Stromal Infiltrating Lymphocytes Are Associated with the Risk of Disease Progression in Mesenchymal Circulating Tumor Cell-Positive Primary Breast Cancer Patients

Circulating tumor cells (CTCs) and the immune infiltration of tumors are closely related to clinical outcomes. This study aimed to verify the influence of stromal lymphocyte infiltration and the immune context of tumor microenvironment on the hematogenous spread and prognosis of 282 chemotherapy naïve primary BC patients. To detect the presence of mesenchymal CTCs, RNA extracted from CD45-depleted peripheral blood was interrogated for the expression of mesenchymal gene transcripts. Tumor-infiltrating lymphocytes (TILs) were detected in the stromal areas by immunohistochemistry, using CD3, CD8, and CD45RO antibodies. The concentrations of 51 plasma cytokines were measured by multiplex bead arrays. TILs infiltration in mesenchymal CTC-positive patients significantly decreased their progression-free survival (HR = 4.88, 95% CI 2.30–10.37, p < 0.001 for CD3^high; HR = 6.17, 95% CI 2.75–13.80, p < 0.001 for CD8^high; HR = 6.93, 95% CI 2.86–16.81, p < 0.001 for CD45RO^high). Moreover, the combination of elevated plasma concentrations of transforming growth factor beta-3 (cut-off 662 pg/mL), decreased monocyte chemotactic protein-3 (cut-off 52.5 pg/mL) and interleukin-15 (cut-off 17.1 pg/mL) significantly increased the risk of disease recurrence (HR = 4.838, 95% CI 2.048–11.427, p < 0.001). Our results suggest a strong impact of the immune tumor microenvironment on BC progression, especially through influencing the dissemination and survival of more aggressive, mesenchymal CTC subtypes.

Predictors of Neoadjuvant Chemotherapy Response in Breast Cancer: A Review

Neoadjuvant chemotherapy (NAC) largely increases operative chances and improves prognosis of the local advanced breast cancer patients. However, no specific means have been invented to predict the therapy responses of patients receiving NAC. Therefore, we focus on the alterations of tumor tissue-related microenvironments such as stromal tumor-infiltrating lymphocytes status, cyclin-dependent kinase expression, non-coding RNA transcription or other small molecular changes, in order to detect potentially predicted biomarkers which reflect the therapeutic efficacy of NAC in different subtypes of breast cancer. Further, possible mechanisms are also discussed to discover feasible treatment targets. Thus, these findings will be helpful to promote the prognosis of breast cancer patients who received NAC and summarized in this review.

Hashimoto's thyroiditis attenuates progression of papillary thyroid carcinoma: deciphering immunological links

Although some studies have investigated the clinicopathologic relationships between papillary thyroid carcinoma (PTC) and Hashimoto's thyroiditis (HT), there is still no clear understanding of differences in tumor immune microenvironment for PTC with coexisting HT and HT effect on PTC progression. The aim of this study was to clarify immune-mediated mechanisms of coexisting HT, which might influence PTC progression. 30 patients with histologically confirmed conventional-type PTC and 30 patients with PTC and coexisting HT were enrolled in the study. To analyze the role of immune-mediated links between PTC and HT, immunohistochemical investigation was conducted to count the number of different immune cells including T-cytotoxic cells (CD8), plasma cells (CD138), Treg cells (FOXP3), mast cells (MCT), and M2 macrophages (CD163). It was shown that despite the high number of immune cells in the intact thyroid tissues of PTC patients with coexisting HT there were no significant differences in M2 macrophages, mast cells and Treg counts inside PTC with or without HT. PTC with HT was associated with a higher number of CD8+ cells (P < 0.001) reflecting the ability of immune system to generate and recruit T-cytotoxic cells in tumor area, which can explain the protective effect of HT on PTC progression. Lymph node metastases development was associated with an increased number of mast cells, M2 macrophages and Treg along with a decreased plasma cells count regardless of coexisting HT. However, we did not find significant differences in T-cytotoxic cells quantity in node-positive and node-negative patients with or without HT, which encourages further investigation of immune escape mechanisms in PTC.

Survival after a cancer diagnosis among solid organ transplant recipients in the United States

BACKGROUND

Transplant recipients have an elevated risk of cancer because of immunosuppressive medications used to prevent organ rejection, but to the authors' knowledge no study to date has comprehensively examined associations between transplantation status and mortality after a cancer diagnosis.

METHODS

The authors assessed cases in the US general population (N=7,147,476) for 16 different cancer types as ascertained from 11 cancer registries. The presence of a solid organ transplant prior to diagnosis (N=11,416 cancer cases) was identified through linkage with the national transplantation registry (1987-2014). Cox models were used to examine the association between transplantation status and cancer-specific mortality, adjusting for demographic characteristics and cancer stage.

RESULTS

For the majority of cancers, cancer-specific mortality was higher in transplant recipients compared with other patients with cancer. The increase was particularly pronounced for melanoma (adjusted hazard ratio [aHR], 2.59; 95% confidence interval [95% CI], 2.18-3.00) and cancers of the breast (aHR, 1.88; 95% CI, 1.61-2.19), bladder (aHR, 1.85; 95% CI, 1.58-2.17), and colorectum (aHR, 1.77; 95% CI, 1.60-1.96), but it also was increased for cancers of the oral cavity/pharynx, stomach, pancreas, kidney, and lung as well as diffuse large B-cell lymphoma (aHR range, 1.21-1.47). Associations remained significant after adjustment for first-course cancer treatment and generally were stronger among patients with local-stage cancers for whom potentially curative treatment was provided, including patients with melanoma (aHR, 3.82; 95% CI, 2.94-4.97) and cancers of the colorectum (aHR, 2.77; 95% CI, 2.07-3.70), breast (aHR, 2.08; 95% CI, 1.50-2.88), and prostate (aHR, 1.60; 95% CI, 1.12-2.29), despite the lack of an association for prostate cancer overall.

CONCLUSIONS

For multiple cancer types, transplant recipients with cancer appear to have an elevated risk of dying of their cancer, even after adjustment for stage and treatment, which may be due to impaired immunity.

Expression of NK Cell Surface Receptors in Breast Cancer Tissue as Predictors of Resistance to Antineoplastic Treatment

Background:

Currently, one of the most used strategies for the treatment of newly diagnosed patients with breast cancer is neoadjuvant chemotherapy based on the application of taxanes and anthracyclines. However, despite the high number of patients who develop a complete pathological clinical response, resistance and relapse following this therapy continue to be a clinical challenge. As a component of the innate immune system, the cytotoxic function of Natural Killer (NK) cells plays an important role in the elimination of tumor cells. However, the role of NK cells in resistance to systemic therapy in breast cancer remains unclear. The present project aims to evaluate the gene expression profile of human NK cells in breast cancer tissue resistant to treatment with taxanes–anthracyclines.

Methods:

Biopsies from tumor tissues were obtained from patients with breast cancer without prior treatment. Histopathological analysis and ex vivo exposure to antineoplastic chemotherapeutics were carried out. Alamar blue and lactate dehydrogenase release assays were performed for quantitative analysis of tumor viability. Gene expression profiles from tumor tissues without prior exposure to therapeutic drugs were analyzed by gene expression microarrays and verified by polymerase chain reaction.

Results:

A significant decrease in gene expression of cell-surface receptors related to NK cells was observed in tumor samples resistant to antineoplastic treatment compared with those that were sensitive to treatment.

Conclusion:

A decrease in NK cell infiltration into tumor tissue might be a predictive marker for failure of chemotherapeutic treatment in breast cancer.

Clinicopathological predictors of long-term benefit in breast cancer treated with neoadjuvant chemotherapy

AIM

To investigate the survival impact of clinicopathological factors, including pathological complete response (pCR) and tumor-infiltrating lymphocytes (sTIL) levels according to subtypes, in breast cancer (BC) patients who received neo-adjuvant chemotherapy (NAC).

METHODS

We evaluated 435 BC patients who presented and received NAC at the Instituto Nacional de Enfermedades Neoplasicas from 2003 to 2014. sTIL was analyzed as the proportion of tumor stroma occupied by lymphocytes, and was prospectively evaluated on hematoxylin and eosin-stained sections of the preNAC core biopsy. pCR was considered in the absence of infiltrating cancer cells in primary tumor and axillary lymph nodes. Analysis of statistical association between clinical pathological features, sTIL, pCR and survival were carried out using SPSSvs19.

RESULTS

Median age was 49 years (range 24-84 years) and the most frequent clinical stage was IIIB (58.3%). Luminal A, Luminal B, HER2-enriched and (triple-negative) TN phenotype was found in 24.6%, 37.9%, 17.7% and 19.8%, respectively. pCR was observed in 11% and median percentage of sTIL was 40% (2%-95%) in the whole population. pCR was associated to Ct1-2 (P = 0.045) and to high sTIL (P = 0.029) in the whole population. There was a slight trend towards significance for sTIL (P = 0.054) in Luminal A. sTIL was associated with grade III (P < 0.001), no-Luminal A subtype (P < 0.001), RE-negative (P < 0.001), PgR-negative (P < 0.001), HER2-positive (P = 0.002) and pCR (P = 0.029) in the whole population. Longer disease-free survival was associated with grade I-II (P = 0.006), cN0 (P < 0.001), clinical stage II (P = 0.004), ER-positive (P < 0.001), PgR-positive (P < 0.001), luminal A (P < 0.001) and pCR (P = 0.002). Longer disease-free survival was associated with grade I-II in Luminal A (P < 0.001), N0-1 in Luminal A (P = 0.045) and TNBC (P = 0.01), clinical stage II in Luminal A (P = 0.003) and TNBC (P = 0.038), and pCR in TNBC (P < 0.001). Longer overall survival was associated with grade I-II (P < 0.001), ER-positive (P < 0.001), PgR-positive (P < 0.001), Luminal A (P < 0.001), cN0 (P = 0.002) and pCR (P = 0.002) in the whole population. Overall survival was associated with clinical stage II (P = 0.017) in Luminal A, older age (P = 0.042) in Luminal B, and pCR in TNBC (P = 0.005).

CONCLUSION

Predictive and prognostic values of clinicopathological features, like pCR and sTIL, differ depending on the evaluated molecular subtype

Trial Watch-Small molecules targeting the immunological tumor microenvironment for cancer therapy

Progressing malignancies establish robust immunosuppressive networks that operate both systemically and locally. In particular, as tumors escape immunosurveillance, they recruit increasing amounts of myeloid and lymphoid cells that exert pronounced immunosuppressive effects. These cells not only prevent the natural recognition of growing neoplasms by the immune system, but also inhibit anticancer immune responses elicited by chemo-, radio- and immuno therapeutic interventions. Throughout the past decade, multiple strategies have been devised to counteract the accumulation or activation of tumor-infiltrating immunosuppressive cells for therapeutic purposes. Here, we review recent preclinical and clinical advances on the use of small molecules that target the immunological tumor microenvironment for cancer therapy. These agents include inhibitors of indoleamine 2,3-dioxigenase 1 (IDO1), prostaglandin E2, and specific cytokine receptors, as well as modulators of intratumoral purinergic signaling and arginine metabolism.

Similar lymphocytic infiltration pattern in primary breast cancer and their corresponding distant metastases

Tumor infiltrating lymphocytes in primary breast cancer (TIL) are acknowledged measures of disease free survival (DFS) in adjuvant and neoadjuvant settings. Little is known about the biology of metastasis infiltrating lymphocytes (mTIL) although the local immunity of the metastatic site may critically influence the infiltrate composite. To address this question, we compared mTIL with their matched TIL in 87 breast cancer patients and their corresponding distant metastasis at four different anatomical locations. Sections of surgical specimen were immunohistochemically analyzed for CD4⁺, CD8⁺ and CD20⁺ lymphocytes in three different tumor compartments: intratumoral lymphocytes (iTIL) defined as lymphocytes in direct contact with breast cancer cells, stromal lymphocytes (sTIL) located within the intratumoral stromal tissue and invasive-margin lymphocytes (imTIL). Overall, we found fewer (p < 0.001) mTIL than TIL. Within the tumor compartments, imTIL were more frequent than sTIL and iTIL both within metastases and the matched primary tumors (PT) (p < 0.001). CD4⁺ T cells were more numerous than CD8⁺ T cells and CD20⁺ B cells (p < 0.001). There was a similar pattern in PT and their corresponding metastasis. Only patients with brain metastases differed from the others displaying less CD20⁺ B cells at the infiltrative margin of the PT (p < 0.05).

In summary, mTIL were significantly reduced within metastases but still mirrored the infiltrate pattern of the PT, interestingly regardless of the metastatic anatomical locations investigated. Our results suggest that the PT assigns the infiltrating lymphocyte pattern resumed at the metastatic site.

Estrogen Receptor Expression Is Associated with DNA Repair Capacity in Breast Cancer

Estrogen-receptor-positive (ER+) tumors employ complex signaling that engages in crosstalk with multiple pathways through genomic and non-genomic regulation. A greater understanding of these pathways is important for developing improved biomarkers that can better determine treatment choices, risk of recurrence and cancer progression. Deficiencies in DNA repair capacity (DRC) is a hallmark of breast cancer (BC); therefore, in this work we tested whether ER signaling influences DRC. We analyzed the association between ER positivity (% receptor activation) and DRC in 270 BC patients, then further stratified our analysis by HER2 receptor status. Our results show that among HER2 negative, the likelihood of having low DRC values among ER- women is 1.92 (95% CI: 1.03, 3.57) times the likelihood of having low DRC values among ER+ women, even adjusting for different potential confounders (p<0.05); however, a contrary pattern was observed among HER2 positives women. In conclusion, there is an association between DRC levels and ER status, and this association is modified by HER2 receptor status. Adding a DNA repair capacity test to hormone receptor testing may provide new information on defective DNA repair phenotypes, which could better stratify BC patients who have ER+ tumors. ER+/HER2- tumors are heterogeneous, incompletely defined, and clinically challenging to treat; the addition of a DRC test could better characterize and classify these patients as well as help clinicians select optimal therapies, which could improve outcomes and reduce recurrences.

Integration of genomic, transcriptomic and proteomic data identifies two biologically distinct subtypes of invasive lobular breast cancer

Invasive lobular carcinoma (ILC) is the second most frequently occurring histological breast cancer subtype after invasive ductal carcinoma (IDC), accounting for around 10% of all breast cancers. The molecular processes that drive the development of ILC are still largely unknown. We have performed a comprehensive genomic, transcriptomic and proteomic analysis of a large ILC patient cohort and present here an integrated molecular portrait of ILC. Mutations in CDH1 and in the PI3K pathway are the most frequent molecular alterations in ILC. We identified two main subtypes of ILCs: (i) an immune related subtype with mRNA up-regulation of PD-L1, PD-1 and CTLA-4 and greater sensitivity to DNA-damaging agents in representative cell line models; (ii) a hormone related subtype, associated with Epithelial to Mesenchymal Transition (EMT), and gain of chromosomes 1q and 8q and loss of chromosome 11q. Using the somatic mutation rate and eIF4B protein level, we identified three groups with different clinical outcomes, including a group with extremely good prognosis. We provide a comprehensive overview of the molecular alterations driving ILC and have explored links with therapy response. This molecular characterization may help to tailor treatment of ILC through the application of specific targeted, chemo- and/or immune-therapies.

A Perspective of Immunotherapy for Breast Cancer: Lessons Learned and Forward Directions for All Cancers

Immunotherapy for cancer has been a focus 50 years ago. At the time, this treatment was developed prior to cloning of the cytokines, no knowledge of regulatory T-cells, and very little information that mesenchymal stem cells (MSCs) (originally colony forming unit-fibroblasts [CFU-F]) could be licensed by the inflammatory microenvironment to suppress an immune response. Given the information available at that time, mononuclear cells from the peripheral blood were activated ex vivo and then replaced in the patients with tumor. The intent was to harness these activated immune cells to target the cancer cells. These studies did not lead to long-term responses because the activated cells when reinfused into the patients were an advantage to the resident MSCs, which can home the tumor and then become suppressive in the presence of the immune cells. The immune suppression caused by MSCs would also expand regulatory T-cells, resulting instead in tumor protection. As time progressed, these different fields converged into a new approach to use immunotherapy for cancer. This article discusses these approaches and also reviews chimeric antigen receptor in the context of future treatments for solid tumors, including breast cancer.

Improved Natural Killer cell activity and retained anti-tumor CD8(+) T cell responses contribute to the induction of a pathological complete response in HER2-positive breast cancer patients undergoing neoadjuvant chemotherapy

Background

Locally advanced HER2-overexpressing breast cancer (BC) patients achieve a high rate of pathological complete responses (pCR) after neoadjuvant chemotherapy (NC). The apparently unaltered immune proficiency of these patients together with the immune-modulating activities of NC drugs suggest a potential contribution of host immunity in mediating clinical responses. We thus performed an extensive immunomonitoring in locally advanced BC patients undergoing NC to identify immunological correlates of pCR induction.

Methods

The immune profile of 40 HER2-positive and 38 HER2-negative BC patients was characterized at diagnosis and throughout NC (Paclitaxel and Trastuzumab, or Docetaxel and Epirubicin, respectively). The percentages of circulating immune cell subsets including T and B lymphocytes, Natural Killer (NK) cells, regulatory T cells, T helper 17 lymphocytes, were quantified by multiparametric flow cytometry. NK cells functional activity was evaluated through the analysis of NF-kB nuclear translocation by Multispectral flow cytometry, and with the in vitro monitoring of Trastuzumab-mediated antibody-dependent cell cytotoxicity (ADCC). CD8⁺ T cell responses against six different tumor-associated antigens (TAA) were characterized by IFN-γ ELISPOT and IFN-γ/IL-2 DualSpot assays.

Results

After NC, HER2-positive patients showed a significant increase in the number of NK cells and regulatory T cells irrespective of the pathological response, whereas patients undergoing a pCR disclosed higher percentages of T helper 17 cells. Notably, a significant increase in the number of activated NK cells was observed only in HER2-positive patients achieving a pCR. Characterization of anti-tumor T cell responses highlighted sustained levels of CD8⁺ T cells specific for survivin and mammaglobin-A throughout NC in patients undergoing a pCR in both arms. Moreover, HER2-positive patients achieving a pCR were characterized by a multi-epitopic and polyfunctional anti-tumor T cell response, markedly reduced in case of partial response.

Conclusions

These results indicate that maintenance of functional T cell responses against selected antigens and improvement of NK cell proficiency during NC are probably critical requirements for pCR induction, especially in HER2-positive BC patients.

Trail registration: Trial registration number: NCT02307227, registered on ClinicalTrials.gov (http://www.clinicaltrials.gov, November 26, 2014).

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0567-0) contains supplementary material, which is available to authorized users.