Presence of mature DC-Lamp+ dendritic cells in sentinel and non-sentinel lymph nodes of breast cancer patients

Dendritic Cell Subpopulations Are Associated with Prognostic Characteristics of Breast Cancer after Neoadjuvant Chemotherapy-An Observational Study

Breast cancer (BC) is the most prevalent malignancy in women and researchers have strived to develop optimal strategies for its diagnosis and management. Neoadjuvant chemotherapy (NAC), which reduces tumor size, risk of metastasis and patient mortality, often also allows for a de-escalation of breast and axillary surgery. Nonetheless, complete pathological response (pCR) is achieved in no more than 40% of patients who underwent NAC. Dendritic cells (DCs) are professional antigen-presenting cells present in the tumor microenvironment. The multitude of their subtypes was shown to be associated with the pathological and clinical characteristics of BC, but it was not evaluated in BC tissue after NAC. We found that highe r densities of CD123+ plasmacytoid DCs (pDCs) were present in tumors that did not show pCR and had a higher residual cancer burden (RCB) score and class. They were of higher stage and grade and more frequently HER2-negative. The density of CD123+ pCDs was an independent predictor of pCR in the studied group. DC-LAMP+ mature DCs (mDCs) were also related to characteristics of clinical relevance (i.e., pCR, RCB, and nuclear grade), although no clear trends were identified. We conclude that CD123+ pDCs are candidates for a novel biomarker of BC response to NAC.

Mature dendritic cells enriched in immunoregulatory molecules (mregDCs): A novel population in the tumour microenvironment and immunotherapy target

BACKGROUND

Dendritic cells (DCs) mediate divergent immune effects by activating T cells or negatively regulating the immune response to promote immune tolerance. They perform specific functions determined by their tissue distribution and maturation state. Traditionally, immature and semimature DCs were described to have immunosuppressive effects, leading to immune tolerance. Nonetheless, recent research has demonstrated that mature DCs can also suppress the immune response under certain circumstances.

MAIN BODY

Mature DCs enriched in immunoregulatory molecules (mregDCs) have emerged as a regulatory module across species and tumour types. Indeed, the distinct roles of mregDCs in tumour immunotherapy have sparked the interest of researchers in the field of single-cell omics. In particular, these regulatory cells were found to be associated with a positive response to immunotherapy and a favourable prognosis.

CONCLUSION

Here, we provide a general overview of the latest and most notable advances and recent findings regarding the basic features and complex roles of mregDCs in nonmalignant diseases and the tumour microenvironment. We also emphasise the important clinical implications of mregDCs in tumours.

Presence of Dendritic Cell Subsets in Sentinel Nodes of Breast Cancer Patients Is Related to Nodal Burden

BACKGROUND: Sentinel lymph nodes (SLNs) are both the first site where breast cancer (BC) metastases form and where anti-tumoral immunity develops. Despite being the most potent antigen-presenting cells, dendritic cells (DCs) located in a nodal tissue can both promote or suppress immune response against cancer in SLNs. METHODS: In SLNs excisions obtained from 123 invasive BC patients, we performed immunohistochemistry (IHC) for CD1a, CD1c, DC-LAMP, and DC-SIGN to identify different DCs populations. Then we investigated the numbers of DCs subsets in tumor-free, micrometastatic, and macrometastatic SLNs with the use of a light microscope. RESULTS: We observed that CD1c+ and DC-SIGN+ DCs were more numerous in SLNs with a larger tumor size. More abundant intratumoral DC-LAMP+ population was related to a higher number of metastatic lymph nodes. Conversely, more abundant CD1a+ DCs were associated with a decreasing nodal burden in SLNs and a lower number of involved lymph nodes. Moreover, densities of the investigated DC populations differed with respect to tumor grade, HER2 overexpression, hormone receptor status, and histologic type of BC. CONCLUSIONS: According to their subtype, DCs are associated with either lower or higher nodal burden in SLNs from invasive BC patients. These relationships appear to be dependent not only on the maturation state of DCs but also on the histological and biological characteristics of the tumor.

Immunologic and immunogenomic aspects of tumor progression

Tumor progression to metastatic disease is characterized by continuous genetic alterations due to instability of the genome. Immune sensitivity was found to be linked to tumor mutational burden (TMB) and the resulting amount of neoantigens. However, APOBEC activity resulting in increase in TMB causes immune evasion. On the other hand, clonal or acquired genetic loss of HLA class I also hampers immune sensitivity of tumors. Rare amplification of the PD-L1 gene in cancers may render them sensitive to immune checkpoint inhibitors but involvement of broader regions of chromosome 9p may ultimately lead again to immune evasion due to inactivation of the IFN-γ signaling pathway. Such genetic changes may occur not only in the primary tumor but at any phase of progression: in lymphatic as well as in visceral metastases. Accordingly, it is rational to monitor these changes continuously during disease progression similar to target therapies. Moreover, beside temporal variability, genomic features of tumors such as mutation profiles, as well as the tumor immune microenvironment also show considerable inter- and intratumoral spatial heterogeneity, suggesting the necessity of multiple sampling in biomarker studies.

Selectively hampered activation of lymph node-resident dendritic cells precedes profound T cell suppression and metastatic spread in the breast cancer sentinel lymph node

BACKGROUND

Immune regulated pathways influence both breast cancer (BrC) development and response to (neo)adjuvant chemotherapy. The sentinel lymph node (SLN), as the first metastatic site, is also the first site where BrC-induced suppression of immune effector subsets occurs. Since intricate knowledge of the phenotypic and functional status of these immune effector subsets is lacking, we set out to map the immune landscape of BrC SLN.

METHODS

Viable LN cells from BrC SLN (n = 58) were used for detailed flowcytometry-assisted mapping of the immune landscape of BrC SLN in a comparative analysis with healthy (i.e. prophylactic mastectomy-derived) axillary lymph nodes (HLN, n = 17). Findings were related to clinicopathological characteristics.

RESULTS

Our data show that BrC-induced immune suppression in tumor-involved SLN, as evidenced by increased Treg and MDSC rates as well as by a generalized state of T cell anergy, coincides with hampered activation of LN-resident (LNR) dendritic cell (DC) subsets rather than of migratory DC subsets. Importantly, suppression of these LN-resident DC subsets preceded profoundly disabled T cell effector functions in tumor-involved SLN. Furthermore, we provide evidence that the suppressed state of LNR-cDC is not only related to nodal involvement but is also related to high-risk breast cancer subtypes that lack expression of hormone receptors and may be a negative predictor of disease-free survival.

CONCLUSION

These data thus provide new insights in the mechanisms underlying loco-regional immune suppression induced by BrC and how these relate to clinical outcome. They identify the LNR-cDC subset as a pivotal regulatory node in cellular immune suppressive pathways and therefore as a promising therapeutic target to combat immune suppression and secure the induction of effective antitumor immunity, e.g. in combination with neo-adjuvant chemotherapy. .

Core needle biopsy promotes lung metastasis of breast cancer: An experimental study

Core needle biopsy (CNB) may be used to diagnose early-stage breast cancer, but it may increase the risk of distant metastasis of tumor cells. The aim of the present study was to explore the effect of CNB on the distant metastasis of breast cancer. A total of 30 BALB/c mice were divided into two groups, namely biopsy and non-biopsy groups. The biopsy-related lung metastasis model (biopsy group) was established by the inoculation in the mammary fat pad of the mouse breast cancer cell line 4T1 combined with CNB. Flow cytometry, quantitative polymerase chain reaction analysis, morphological analysis, as well as other techniques, were used to evaluate the biological behavior of the tumors in the mouse model. A stable and reliable lung metastasis model of breast cancer was successfully established. The number of metastatic lung nodules in the biopsy group was significantly higher compared with that in the non-biopsy group (P<0.05). Compared with the non-biopsy group, the mRNA expression of transforming growth factor (TGF)-β1, SOX4 and Ezh2 in the biopsy group was significantly upregulated (P<0.05) and the number of natural killer (NK) cells detected by flow cytometry was increased, but the difference was not statistically significant (P>0.05). Therefore, CNB was found to promote the lung metastasis of breast cancer, and the underlying mechanism may be associated with epithelial-to-mesenchymal transition (EMT) mediated by the TGF-β1 signaling pathway.

Lymph Node Cellular Dynamics in Cancer and HIV: What Can We Learn for the Follicular CD4 (Tfh) Cells?

Lymph nodes (LNs) are central in the generation of adaptive immune responses. Follicular helper CD4 T (Tfh) cells, a highly differentiated CD4 population, provide critical help for the development of antigen-specific B cell responses within the germinal center. Throughout the past decade, numerous studies have revealed the important role of Tfh cells in Human Immunodeficiency Virus (HIV) pathogenesis as well as in the development of neutralizing antibodies post-infection and post-vaccination. It has also been established that tumors influence various immune cell subsets not only in their proximity, but also in draining lymph nodes. The role of local or tumor associated lymph node Tfh cells in disease progression is emerging. Comparative studies of Tfh cells in chronic infections and cancer could therefore provide novel information with regards to their differentiation plasticity and to the mechanisms regulating their development.

Development of automated quantification methodologies of immunohistochemical markers to determine patterns of immune response in breast cancer: a retrospective cohort study

INTRODUCTION

Lymph nodes are one of the main sites where an effective immune response develops. Normally, axillary nodes are the first place where breast cancer produces metastases. Several studies have demonstrated the importance of immune cells, especially dendritic cells, in the evolution of breast cancer. The goal of the project is to identify differences in the patterns of immune infiltrates, with particular emphasis on dendritic cells, in tumour and axillary node biopsies between patients with and without metastases in the axillary nodes at the time of diagnosis. It is expected that these differences will be able to explain differences in survival, relapse and clinicopathological variables between the two groups.

METHODS AND ANALYSIS

The study will involve 100 patients diagnosed with invasive breast cancer between 2000 and 2007, 50% of whom have metastases in the axillary lymph node at diagnosis. In selected patients, two cylinders from biopsies of representative areas of tumour and axillary nodes (with and without metastasis) will be selected and organised in tissue microarrays. Samples will be stained using immunohistochemical techniques for different markers of immune response and dendritic cells. Two images of each cylinder will be captured under standardised conditions for each marker. Each marker will be quantified automatically by digital image procedures using Image-Pro Plus and Image-J software. Associations of survival, relapse and other clinicopathological variables with the automatically quantified levels of immune infiltrates in patients with and without axillary node metastasis will be sought.

ETHICS AND DISSEMINATION

The present project has been approved by the Clinical Research Ethics Committee of the Hospital Universitari Joan XXIII (Ref: 22p/2011). Those patients whose biopsies and clinical data are to be used will give their signed informed consent. Results will be published in peer-reviewed journals.

Immune cell profile of sentinel lymph nodes in patients with malignant melanoma - FOXP3+ cell density in cases with positive sentinel node status is associated with unfavorable clinical outcome

Background

Besides being a preferential site of early metastasis, the sentinel lymph node (SLN) is also a privileged site of T-cell priming, and may thus be an appropriate target for investigating cell types involved in antitumor immune reactions.

Methods

In this retrospective study we determined the prevalence of OX40⁺ activated T lymphocytes, FOXP3⁺ (forkhead box P3) regulatory T cells, DC-LAMP⁺ (dendritic cell-lysosomal associated membrane protein) mature dendritic cells (DCs) and CD123⁺ plasmacytoid DCs by immunohistochemistry in 100 SLNs from 60 melanoma patients. Density values of each cell type in SLNs were compared to those in non-sentinel nodes obtained from block dissections (n = 37), and analyzed with regard to associations with clinicopathological parameters and disease outcome.

Results

Sentinel nodes showed elevated amount of all cell types studied in comparison to non-sentinel nodes. Metastatic SLNs had higher density of OX40⁺ lymphocytes compared to tumor-negative nodes, while no significant difference was observed in the case of the other cell types studied. In patients with positive sentinel node status, high amount of FOXP3⁺ cells in SLNs was associated with shorter progression-free (P = 0.0011) and overall survival (P = 0.0014), while no significant correlation was found in the case of sentinel-negative patients. The density of OX40⁺, CD123⁺ or DC-LAMP⁺ cells did not show significant association with the outcome of the disease.

Conclusions

Taken together, our results are compatible with the hypothesis of functional competence of sentinel lymph nodes based on the prevalence of the studied immune cells. The density of FOXP3⁺ lymphocytes showed association with progression and survival in patients with positive SLN status, while the other immune markers studied did not prove of prognostic importance. These results, together with our previous findings on the prognostic value of activated T cells and mature DCs infiltrating primary melanomas, suggest that immune activation-associated markers in the primary tumor may have a higher impact than those in SLNs on the prognosis of the patients. On the other hand, FOXP3⁺ cell density in SLNs, but not in the primary tumor, was found predictive of disease outcome in melanoma patients.

Feasibility of flowcytometric quantitation of immune effector cell subsets in the sentinel lymph node of the breast after cryopreservation

The sentinel lymph node (SLN) is an emerging focus for immunological research in breast cancer. Cryopreservation of SLN single-cell suspensions allows for simultaneous phenotypic multi-parameter analyses and minimizes operator dependent variability. This is of particular importance for immunomonitoring of large multicenter trials. However, little data are available regarding the influence of cryopreservation on phenotypic characteristics of lymph node dendritic cells and T cells. In this study we assessed the feasibility of cryopreservation of viable SLN cell samples for flowcytometric analysis, by comparing quantitative analyses of SLN cell samples after freeze-thawing with direct analysis of fresh SLN cell samples. SLN were collected from nine breast cancer patients. From each SLN cell sample, half was used for immediate analysis and half was analyzed after cryopreservation and thawing. Conventional dendritic cell (cDC) and T cell subsets were quantified and phenotypically characterized by flow cytometry. The observed frequencies of both CD1a(+) and CD1a(-)CD11c(+)CD14(-) cDC subsets showed significant correlation between the fresh and frozen-thawed samples. Similar high correlations were found for CD83 and CD86 expression markers on the more frequent (>0.2%) CD1a(+) and CD1a(-)CD11c(+)CD14(-) cDC subset, but not on the low-frequency (<0.2%) CD1a(+)CD11c(+)CD14(+) cDC subset. CD4/CD8 T cell ratios were comparable and were significantly correlated pre- and post-freezing. Regulatory CD4(+)CD25(hi) T cell frequencies and their FoxP3 expression levels were significantly higher after freezing-thawing than in the freshly analyzed samples. Nevertheless, a highly significant correlation was found for both parameters pre- and post-freezing. Cryopreservation and thawing seems a valid and practical alternative to direct analysis of fresh viable lymph node cells, without introducing cryo-dependent variance between SLN samples. However, enumeration of low-frequency cell populations and assessment of their marker expression levels are less reliable after cryopreservation and should be assessed and considered in the design of each clinical trial.

Metastasis to sentinel lymph nodes in breast cancer is associated with maturation arrest of dendritic cells and poor co-localization of dendritic cells and CD8+ T cells

The regional immune systems of patients with breast cancer are immunosuppressed. Dendritic cells are professional antigen-presenting cells and present cancer-associated antigens to the adaptive immune system in sentinel lymph nodes. Dendritic cells may promote, or inhibit, an adaptive immune response to specific antigens. Our aim was to assess whether dendritic cells were associated with nodal metastasis in patients with breast cancer. Sentinel lymph nodes of 47 patients with breast cancer with varying degrees of nodal disease and ten controls were evaluated using immunohistochemistry for the accumulation of dendritic cells in general (CD1a(+)), mature dendritic cells (CD208(+)), and plasmacytoid dendritic cells (CD123(+)). Cytotoxic T cell and regulatory T cell accumulation were also evaluated. Sentinel lymph nodes with macrometastases demonstrated fewer mature dendritic cells than sentinel lymph nodes without metastasis (p = 0.028), but not controls. There were fewer mature dendritic cells to cytotoxic T cells in sentinel lymph nodes with metastasis than those without (p = 0.033). Also, there were more regulatory T cells to mature dendritic cells in sentinel lymph nodes with metastasis than those without (p = 0.02). In conclusion, our study suggests that sentinel lymph nodes with metastasis have arrest of maturation of dendritic cells, fewer mature dendritic cell interactions with cytotoxic T cells, and more regulatory T cells than sentinel lymph nodes without metastasis in patients with breast cancer. These findings extend our understanding of regional immunosuppression and suggest that most regional immunosuppressive changes are associated with nodal metastasis in breast cancer.

Regional immunity in melanoma: immunosuppressive changes precede nodal metastasis

In order to characterize the degree of immunosuppression in regional immunity in patients with melanoma, we used immunohistochemistry to analyze markers of T-cell subtype and polarity, costimulation, dendritic cell maturation, monocytes, lymphatic vasculature, and angiogenesis. Specifically, we analyzed expression of CD4, CD8, CD14, CD40, CD86, CD123, HLA-DR, IL-10, LYVE, VEGFR3, and VEGF-C in lymph nodes. We compared sentinel lymph nodes with and without metastasis from patients with melanoma with both infection inflamed (reactive) and dormant human lymph nodes. There were no differences demonstrated between sentinel lymph nodes with or without metastasis from patients with melanoma in any of the markers that were tested. Both groups of sentinel lymph nodes had fewer CD8(+) T cells than either set of control nodes. Whereas the infection inflamed lymph nodes demonstrated Th2 polarity, the dormant lymph nodes demonstrated Th1 polarity. In conclusion, changes in regional immunity appeared to precede metastasis in melanoma. Whether there was tumor present in sentinel lymph nodes or not, these nodes demonstrated a marked decrease in cytotoxic T cells compared with both sets of controls. Furthermore, the control lymph nodes used for comparison can significantly impact interpretation, as the dormant and reactive lymph nodes markedly varied in their immune profiles. These immunologic changes may explain the successful metastasis of melanoma in the midst of the immune environment of the sentinel lymph node, and lend insights into the mechanisms of lymphatic metastases in other solid malignancies.

Distribution and maturity of dendritic cells in diseases of insufficient placentation

PROBLEM

The immunological equilibrium at the feto-maternal interphase contributes towards late gestational diseases like growth restriction (IUGR) pre-eclampsia (PE) and hemolysis, elevated liver enzymes, low platelets (HELLP)-syndrome. The state of activation of decidual dendritic cells (DC) has emerged as one of the central players influencing this immunological equilibrium.

METHOD OF STUDY

Paraffin-embedded tissue sections from 27 pregnancies were immunostained for DC markers DEC-205, DC-SIGN, DC-LAMP and costained for DC-SIGN/CD56 and DC-SIGN/ vascular endothelial growth factor receptor (VEGFR) -1 and -2. We investigated placental tissue of IUGR fetuses and of patients who developed PE or HELLP-syndrome as well as placental tissue derived from normal pregnancies.

RESULTS

We found that expression of DEC-205 and DC-SIGN was significantly upregulated in HELLP placentas, whereas expression of DC-LAMP was abrogated almost entirely. Costaining showed an interaction between DC-SIGN(+) DC and natural killer cells as well as costaining of VEGFR-1 and -2 and DC-SIGN. Pre-eclamptic and IUGR placentas showed no significant change in any of the investigated markers compared to normal controls.

CONCLUSION

Our data suggest a participation of DC-mediated immunological mechanisms in HELLP syndrome.