Low T-cell proportion in the tumor microenvironment is associated with immune escape and poor survival in diffuse large B-cell lymphoma.

The tumor microenvironment (TME) is important in the pathogenesis and prognosis of lymphoma. Previous studies have demonstrated that features of the diffuse large B-cell lymphoma (DLBCL) TME can be associated with prognosis, but questions remain about the mechanisms underlying these TME features, and the interplay between tumor cells and the local TME. Therefore, we performed multispectral immunofluorescence (mIF) using two 6-color panels to interrogate the cellular proportions of T-cell subsets, macrophages, and natural killer cells in 57 cases of de novo DLBCL treated with R-CHOP chemotherapy. We found that very low CD3+ T-cell proportion and low CD4+PD1+ and CD8+PD1+ T cells have poor survival compared to those with a high T-cell proportion. Also, cases with concurrently low TIM3 and PD1 have a poor prognosis. This poor prognosis with low T-cell proportion was validated using immune deconvolution of gene expression profiling data from 351 cases of DLBCL and an additional cohort of 53 cases of DLBCL using routine immunohistochemistry. In addition, cases with loss of B2M, HLA I and/or HLA II protein expression on the tumor cells also had a low T-cell proportion, providing evidence that lack of these proteins allows for immune evasion. Overall, our results show that patients with DLBCL with a low T-cell proportion in the TME have a poor survival when treated with R-CHOP and exhibit mechanisms of immune escape.

Hyperthermic Intraperitoneal Chemotherapy-Induced Molecular Changes in Humans Validate Preclinical Data in Ovarian Cancer.

PURPOSE: Hyperthermic intraperitoneal chemotherapy (HIPEC) confers a survival benefit in epithelial ovarian cancer (EOC) and in preclinical models. However, the molecular changes induced by HIPEC have not been corroborated in humans. PATIENTS AND METHODS: A feasibility trial evaluated clinical and safety outcomes of HIPEC with cisplatin during optimal cytoreductive surgery (CRS) in patients with EOC diagnosed with stage III, IV, or recurrent EOC. Pre- and post-HIPEC biopsies were comprehensively profiled with genomic and transcriptomic sequencing to identify mutational and RNAseq signatures correlating with response; the tumor microenvironment was profiled to identify potential immune biomarkers; and transcriptional signatures of tumors and normal samples before and after HIPEC were compared to investigate HIPEC-induced acute transcriptional changes. RESULTS: Thirty-five patients had HIPEC at the time of optimal CRS; all patients had optimal CRS. The median progression-free survival (PFS) was 24.7 months for primary patients and 22.4 for recurrent patients. There were no grade 4 or 5 adverse events. Anemia was the most common grade 3 adverse event (43%). Hierarchical cluster analyses identified distinct transcriptomic signatures of good versus poor responders to HIPEC correlating with a PFS of 29.9 versus 7.3 months, respectively. Among good responders, significant HIPEC-induced molecular changes included immune pathway upregulation and DNA repair pathway downregulation. Within cancer islands, % programmed cell death protein 1 expression in CD8+ T cells significantly increased after HIPEC. An exceptional responder (PFS 58 months) demonstrated the highest programmed cell death protein 1 increase. Heat shock proteins comprised the top differentially upregulated genes in HIPEC-treated tumors. CONCLUSION: Distinct transcriptomic signatures identify responders to HIPEC, and preclinical model findings are confirmed for the first time in a human cohort.

A Phase 2 Trial Combining Pembrolizumab and Palliative Radiation Therapy in Gastroesophageal Cancer to Augment Abscopal Immune Responses.

PURPOSE: Single agent PD-1 inhibitors have yielded durable responses in a minority of gastroesophageal cancers. Radiation therapy has been recognized to promote antitumor immune responses and may synergize with anti-PD-1 agents. We sought to evaluate if combining palliative radiation therapy with pembrolizumab can augment antitumor immune responses in gastroesophageal cancer. METHODS AND MATERIALS: Patients had metastatic gastroesophageal cancer with indication for palliative radiation therapy with ≥2 disease sites outside of the radiation field assessable for abscopal response and biopsies for laboratory correlative analyses. Palliative radiation was delivered to a dose of 30 Gy over 10 fractions. Pembrolizumab, 200 mg, was administered concurrently intravenously every 3 weeks until disease progression, unacceptable toxicity, or study withdrawal, for up to 2 years. Endpoints included PD-L1 expression in pre- and posttreatment biopsies and abscopal objective response rate per Response Evaluation Criteria in Solid Tumors. RESULTS: Of 14 enrolled patients, the objective response rate was 28.6% (95% confidence interval, 8.4%-58.1%), and the median duration of response was not reached (95% confidence interval, 6.9-NR months). Overall, 2 patients had treatment-related grade 3 to 4 adverse events with no grade 5 events. One patient discontinued therapy due to grade 4 colitis. We did not observe an association between radiation and abscopal changes in PD-L1 expression via assessment of an analogous PD-L1 Combined Positive Score, Tumor Proportion Score, Mononuclear Immune Cell Density Score, or proportion of PD-L1-expressing immune cells between pre- and posttreatment tumor biopsies. CONCLUSIONS: Combining palliative radiation therapy and pembrolizumab provided promising durable responses in this patient population but we were unable to definitively distinguish abscopal biologic changes. Biomarker analyses beyond PD-L1 expression are needed to better understand putative mechanisms and identify patients who will benefit from this approach.

Spatial distribution of B cells and lymphocyte clusters as a predictor of triple-negative breast cancer outcome.

While tumor infiltration by CD8+ T cells is now widely accepted to predict outcomes, the clinical significance of intratumoral B cells is less clear. We hypothesized that spatial distribution rather than density of B cells within tumors may provide prognostic significance. We developed statistical techniques (fractal dimension differences and a box-counting method 'occupancy') to analyze the spatial distribution of tumor-infiltrating lymphocytes (TILs) in human triple-negative breast cancer (TNBC). Our results indicate that B cells in good outcome tumors (no recurrence within 5 years) are spatially dispersed, while B cells in poor outcome tumors (recurrence within 3 years) are more confined. While most TILs are located within the stroma, increased numbers of spatially dispersed lymphocytes within cancer cell islands are associated with a good prognosis. B cells and T cells often form lymphocyte clusters (LCs) identified via density-based clustering. LCs consist either of T cells only or heterotypic mixtures of B and T cells. Pure B cell LCs were negligible in number. Compared to tertiary lymphoid structures (TLS), LCs have fewer lymphocytes at lower densities. Both types of LCs are more abundant and more spatially dispersed in good outcomes compared to poor outcome tumors. Heterotypic LCs in good outcome tumors are smaller and more numerous compared to poor outcome. Heterotypic LCs are also closer to cancer islands in a good outcome, with LC size decreasing as they get closer to cancer cell islands. These results illuminate the significance of the spatial distribution of B cells and LCs within tumors.

CD84 is a regulator of the immunosuppressive microenvironment in multiple myeloma.

Multiple myeloma (MM) is characterized by an accumulation of malignant plasma cells (PCs) within the BM. The BM microenvironment supports survival of the malignant cells and is composed of cellular fractions that foster myeloma development and progression by suppression of the immune response. Despite major progress in understanding the biology and pathophysiology of MM, this disease is still incurable and requires aggressive treatment with significant side effects. CD84 is a self-binding immunoreceptor belonging to the signaling lymphocyte activation molecule (SLAM) family. Previously, we showed that CD84 bridges between chronic lymphocytic leukemia cells and their microenvironment, and it regulates T cell function. In the current study, we investigated the role of CD84 in MM. Our results show that MM cells express low levels of CD84. However, these cells secrete the cytokine macrophage migration inhibitory factor (MIF), which induces CD84 expression on cells in their microenvironment. Its activation leads to an elevation of expression of genes regulating differentiation to monocytic/granulocytic-myeloid-derived suppressor cells (M-MDSCs and G-MDSCs, respectively) and upregulation of PD-L1 expression on MDSCs, which together suppress T cell function. Downregulation of CD84 or its blocking reduce MDSC accumulation, resulting in elevated T cell activity and reduced tumor load. Our data suggest that CD84 might serve as a novel therapeutic target in MM.

Physics approaches to the spatial distribution of immune cells in tumors.

The goal of immunotherapy is to mobilize the immune system to kill cancer cells. Immunotherapy is more effective and, in general, the prognosis is better, when more immune cells infiltrate the tumor. We explore the question of whether the spatial distribution rather than just the density of immune cells in the tumor is important in forecasting whether cancer recurs. After reviewing previous work on this issue, we introduce a novel application of maximum entropy to quantify the spatial distribution of discrete point-like objects. We apply our approach to B and T cells in images of tumor tissue taken from triple negative breast cancer patients. We find that the immune cells are more spatially dispersed in good clinical outcome (no recurrence of cancer within at least 5 years of diagnosis) compared to poor clinical outcome (recurrence within 3 years of diagnosis). Our results highlight the importance of spatial distribution of immune cells within tumors with regard to clinical outcome, and raise new questions on their role in cancer recurrence.

Predicting Relapse in Patients With Triple Negative Breast Cancer (TNBC) Using a Deep-Learning Approach.

The abundance and/or location of tumor infiltrating lymphocytes (TILs), especially CD8+ T cells, in solid tumors can serve as a prognostic indicator in various types of cancer. However, it is often difficult to select an appropriate threshold value in order to stratify patients into well-defined risk groups. It is also important to select appropriate tumor regions to quantify the abundance of TILs. On the other hand, machine-learning approaches can stratify patients in an unbiased and automatic fashion. Based on immunofluorescence (IF) images of CD8+ T lymphocytes and cancer cells, we develop a machine-learning approach which can predict the risk of relapse for patients with Triple Negative Breast Cancer (TNBC). Tumor-section images from 9 patients with poor outcome and 15 patients with good outcome were used as a training set. Tumor-section images of 29 patients in an independent cohort were used to test the predictive power of our algorithm. In the test cohort, 6 (out of 29) patients who belong to the poor-outcome group were all correctly identified by our algorithm; for the 23 (out of 29) patients who belong to the good-outcome group, 17 were correctly predicted with some evidence that improvement is possible if other measures, such as the grade of tumors, are factored in. Our approach does not involve arbitrarily defined metrics and can be applied to other types of cancer in which the abundance/location of CD8+ T lymphocytes/other types of cells is an indicator of prognosis.

Multi-panel immunofluorescence analysis of tumor infiltrating lymphocytes in triple negative breast cancer: Evolution of tumor immune profiles and patient prognosis.

The evolutionary changes in immune profiles of triple negative breast cancer (TNBC) are not well understood, although it is known that immune checkpoint inhibitors have diminished activity in heavily pre-treated TNBC patients. This study was designed to characterize immune profile changes of longitudinal tumor specimens by studying immune subsets of tumor infiltrating lymphocytes (TILs) in paired primary and metastatic TNBC in a cohort of "poor outcome" (relapsed within 5 years) patients. Immune profiles of TNBCs in a cohort of "good outcome" (no relapse within 5 years) patients were also analyzed. Immune subsets were characterized for CD4, CD8, FOXP3, CD20, CD33, and PD1 using immuno-fluorescence staining in stroma, tumor, and combined stroma and tumor tissue. TIL subsets in "good outcome" versus "poor outcome" patients were also analyzed. Compared with primary, metastatic TNBCs had significantly lower TILs by hematoxylin and eosin (H&E) staining. Stromal TILs (sTILs), but not tumoral TILs (tTILs) had significantly reduced cytotoxic CD8+ T cells (CTLs), PD1+ CTLs, and total PD1+ TILs in metastatic compared with matched primary TNBCs. Higher PD1+ CTLs, PD1+CD4+ helper T cells (PD1+TCONV) and all PD1+ T cells in sTILs, tTILs and total stromal and tumor TILS (s+tTIL) were all associated with better prognosis. In summary, TIL subsets decrease significantly in metastatic TNBCs compared with matched primary. Higher PD1+ TILs are associated with better prognosis in early stage TNBCs. This finding supports the application of immune checkpoint inhibitors early in the treatment of TNBCs.

Resident memory CD8+ T cells within cancer islands mediate survival in breast cancer patients.

CD8+ tumor-infiltrating lymphocytes (TILs) correlate with relapse-free survival (RFS) in most cancer types, including breast cancer. However, subset composition, functional status, and spatial location of CD8+ TILs in relation to RFS in human breast tumors remain unclear. Spatial tissue analysis via quantitative immunofluorescence showed that infiltration of CD8+ T cells into cancer islands was more significantly associated with RFS than CD8+ T cell infiltration into either tumor stroma or total tumor. Localization into cancer islands within tumors is mediated by expression of the integrin CD103, which is a marker for tissue-resident memory T cells (TRMs). Analysis of fresh tumor samples revealed that CD8+ TRMs are functionally similar to other CD8+ TILs, suggesting that the basis of their protective effect is their spatial distribution rather than functional differences. Indeed, CD103+ TRMs, as compared with CD103-CD8+ TILs, are enriched within cancer islands, and CD8+ TRM proximity to cancer cells drives the association of CD8+ TIL densities with RFS. Together, these findings reveal the importance of cancer island-localized CD8+ TRMs in surveillance of the breast tumor microenvironment and as a critical determinant of RFS in patients with breast cancer.

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.

Sentinel lymph node B cells can predict disease-free survival in breast cancer patients.

Tumor invasion into draining lymph nodes, especially sentinel lymph nodes (SLNs), is a key determinant of prognosis and treatment in breast cancer as part of the TNM staging system. Using multicolor histology and quantitative image analysis, we quantified immune cells within SLNs from a discovery cohort of 76 breast cancer patients. We found statistically more in situ CD3+ T cells in tumor negative vs. tumor positive nodes (mean of 8878 vs. 6704, respectively, p = 0.006), but no statistical difference in CD20+ B cells or CD1a+ dendritic cells. In univariate analysis, a reduced hazard was seen with a unit increase in log CD3 with HR 0.49 (95% CI 0.30-0.80) and log CD20 with HR 0.37 (95% CI 0.22-0.62). In multivariate analysis, log CD20 remained significant with HR 0.42 (95% CI 0.25-0.69). When restricted to SLN tumor negative patients, increased log CD20 was still associated with improved DFS (HR = 0.26, 95% CI 0.08-0.90). The CD20 results were validated in a separate cohort of 21 patients (n = 11 good outcome, n = 10 poor outcome) with SLN negative triple-negative breast cancer (TNBC) ("good" mean of 7011 vs. "poor" mean of 4656, p = 0.002). Our study demonstrates that analysis of immune cells within SLNs, regardless of tumor invasion status, may provide additional prognostic information, and highlights B cells within SLNs as important in preventing future recurrence.

Complete regression of cutaneous metastases with systemic immune response in a patient with triple negative breast cancer receiving p53MVA vaccine with pembrolizumab.

A heavily pretreated patient with triple negative breast cancer distinguished by cutaneous metastases received p53MVA vaccine in combination with pembrolizumab. Her cutaneous metastases regressed and after 2 cycles of therapy, a skin biopsy showed a complete pathological response. Systemic response was confirmed with restaging CT and bone scans. Activation of p53-specific T cell responses and elevation of multiple immune response genes in peripheral blood correlated with the rapid clinical response which lasted for 6 months after the initiation of combined therapy.

On the mechanism of long-range orientational order of fibroblasts.

Long-range alignment ordering of fibroblasts have been observed in the vicinity of cancerous tumors and can be recapitulated with in vitro experiments. However, the mechanisms driving their ordering are not understood. Here, we show that local collision-driven nematic alignment interactions among fibroblasts are insufficient to explain observed long-range alignment. One possibility is that there exists another orientation field coevolving with the cells and reinforcing their alignment. We propose that this field reflects the mechanical cross-talk between the fibroblasts and the underlying fibrous material on which they move. We show that this long-range interaction can give rise to high nematic order and to the observed patterning of the cancer microenvironment.