Correlation of metabolic information on FDG-PET with tissue expression of immune markers in patients with non-small cell lung cancer (NSCLC) who are candidates for upfront surgery.

PURPOSE: Eliciting antitumor T-cell response by targeting the PD-1/PD-L1 axis with checkpoint inhibitors has emerged as a novel therapeutic strategy in non-small cell lung cancer (NSCLC). The identification of predictors for sensitivity or resistance to these agents is, therefore, needed. Herein, we investigate the correlation of metabolic information on FDG-PET with tissue expression of immune-checkpoints and other markers of tumor-related immunity in resected NSCLC patients. MATERIALS AND METHODS: All patients referred to our institution for upfront surgical resection of NSCLC, who were investigated with FDG-PET prior to surgery, were consecutively included in the study. From January 2010 to May 2014, 55 patients (stage IA-IIIB; M:F = 42:13; mean age 68.9 years) were investigated. Sampled surgical tumor specimens were analyzed by immunohistochemistry (IHC) for CD68-TAMs (tumor-associated macrophages), CD8-TILs (tumor infiltrating lymphocytes), PD-1-TILs, and PD-L1 tumor expression. Immunoreactivity was evaluated, and scores were compared with imaging findings. FDG-PET images were analyzed to define semi-quantitative parameters: SUVmax and SUVmean. Metabolic information on FDG-PET was correlated with tissue markers expression and disease-free survival (DFS) considering a median follow-up of 16.2 months. RESULTS: Thirty-six adenocarcinomas (ADC), 18 squamous cell carcinomas (SCC), and one sarcomatoid carcinoma were analyzed. All tumors resulted positive at FDG-PET: median SUVmax 11.3 (range: 2.3-32.5) and SUVmean 6.4 (range: 1.5-13) both resulted significantly higher in SCC compared to other NSCLC histotypes (p = 0.007 and 0.048, respectively). IHC demonstrated a median immunoreactive surface covered by CD68-TAMs of 5.41 % (range: 0.84-14.01 %), CD8-TILs of 2.9 % (range: 0.11-11.92 %), PD-1 of 0.65 % (range: 0.02-5.87 %), and PD-L1 of 0.7 % (range: 0.03-10.29 %). We found a statistically significant correlation between SUVmax and SUVmean with the expression of CD8 TILs (rho = 0.31; p = 0.027) and PD-1 (rho = 0.33; p = 0.017 and rho = 0.36; p = 0.009, respectively). The other tissue markers correlated as follows: CD8 TILs and PD-1 (rho = 0.45; p = 0.001), CD8 TILs and PD-L1 (rho = 0.41; p = 0.003), CD68-TAMs and PD-L1 (rho = 0.30; p = 0.027), PD-1 and PD-L1 (rho = 0.26; p = 0.059). With respect to patients' outcome, SUVmax, SUVmean, and disease stage showed a statistically significant correlation with DFS (p = 0.002, 0.004, and <0.001, respectively). CONCLUSIONS: The present study shows a direct association between metabolic parameters on FDG-PET and the expression of tumor-related immunity markers, suggesting a potential role for FDG-PET to characterize the tumor microenvironment and select NSCLC patients candidate to checkpoint inhibitors.

Tailored chemokine receptor modification improves homing of adoptive therapy T cells in a spontaneous tumor model.

In recent years, tumor Adoptive Cell Therapy (ACT), using administration of ex vivo-enhanced T cells from the cancer patient, has become a promising therapeutic strategy. However, efficient homing of the anti-tumoral T cells to the tumor or metastatic site still remains a substantial hurdle. Yet the tumor site itself attracts both tumor-promoting and anti-tumoral immune cell populations through the secretion of chemokines. We attempted to identify these chemokines in a model of spontaneous metastasis, in order to "hijack" their function by expressing matching chemokine receptors on the cytotoxic T cells used in ACT, thus allowing us to enhance the recruitment of these therapeutic cells. Here we show that this enabled the modified T cells to preferentially home into spontaneous lymph node metastases in the TRAMP model, as well as in an inducible tumor model, E.G7-OVA. Due to the improved homing, the modified CD8+ T cells displayed an enhanced in vivo protective effect, as seen by a significant delay in E.G7-OVA tumor growth. These results offer a proof of principle for the tailored application of chemokine receptor modification as a means of improving T cell homing to the target tumor, thus enhancing ACT efficacy. Surprisingly, we also uncover that the formation of the peri-tumoral fibrotic capsule, which has been shown to impede T cell access to tumor, is partially dependent on host T cell presence. This finding, which would be impossible to observe in immunodeficient model studies, highlights possible conflicting roles that T cells may play in a therapeutic context.

Spatial distribution of B cells predicts prognosis in human pancreatic adenocarcinoma.

B-cell responses are emerging as critical regulators of cancer progression. In this study, we investigated the role of B lymphocytes in the microenvironment of human pancreatic ductal adenocarcinoma (PDAC), in a retrospective consecutive series of 104 PDAC patients and in PDAC preclinical models. Immunohistochemical analysis revealed that B cells occupy two histologically distinct compartments in human PDAC, either scatteringly infiltrating (CD20-TILs), or organized in tertiary lymphoid tissue (CD20-TLT). Only when retained within TLT, high density of B cells predicted longer survival (median survival 16.9 mo CD20-TLThi vs. 10.7 mo CD20-TLTlo; p = 0.0085). Presence of B cells within TLT associated to a germinal center (GC) immune signature, correlated with CD8-TIL infiltration, and empowered their favorable prognostic value. Immunotherapeutic vaccination of spontaneously developing PDAC (KrasG12D-Pdx1-Cre) mice with α-enolase (ENO1) induced formation of TLT with active GCs and correlated with increased recruitment of T lymphocytes, suggesting induction of TLT as a strategy to favor mobilization of immune cells in PDAC. In contrast, in an implanted tumor model devoid of TLT, depletion of B cells with an anti-CD20 antibody reinstated an antitumor immune response. Our results highlight B cells as an essential element of the microenvironment of PDAC and identify their spatial organization as a key regulator of their antitumor function. A mindfully evaluation of B cells in human PDAC could represent a powerful prognostic tool to identify patients with distinct clinical behaviors and responses to immunotherapeutic strategies.

Dual prognostic significance of tumour-associated macrophages in human pancreatic adenocarcinoma treated or untreated with chemotherapy.

OBJECTIVE: Tumour-associated macrophages (TAMs) play key roles in tumour progression. Recent evidence suggests that TAMs critically modulate the efficacy of anticancer therapies, raising the prospect of their targeting in human cancer. DESIGN: In a large retrospective cohort study involving 110 patients with pancreatic ductal adenocarcinoma (PDAC), we assessed the density of CD68-TAM immune reactive area (%IRA) at the tumour-stroma interface and addressed their prognostic relevance in relation to postsurgical adjuvant chemotherapy (CTX). In vitro, we dissected the synergism of CTX and TAMs. RESULTS: In human PDAC, TAMs predominantly exhibited an immunoregulatory profile, characterised by expression of scavenger receptors (CD206, CD163) and production of interleukin 10 (IL-10). Surprisingly, while the density of TAMs associated to worse prognosis and distant metastasis, CTX restrained their protumour prognostic significance. High density of TAMs at the tumour-stroma interface positively dictated prognostic responsiveness to CTX independently of T-cell density. Accordingly, in vitro, gemcitabine-treated macrophages became tumoricidal, activating a cytotoxic gene expression programme, inhibiting their protumoural effect and switching to an antitumour phenotype. In patients with human PDAC, neoadjuvant CTX was associated to a decreased density of CD206(+) and IL-10(+) TAMs at the tumour-stroma interface. CONCLUSIONS: Overall, our data highlight TAMs as critical determinants of prognostic responsiveness to CTX and provide clinical and in vitro evidence that CTX overall directly re-educates TAMs to restrain tumour progression. These results suggest that the quantification of TAMs could be exploited to select patients more likely to respond to CTX and provide the basis for novel strategies aimed at re-educating macrophages in the context of CTX.

Tertiary lymphoid tissue in the tumor microenvironment: from its occurrence to immunotherapeutic implications.

Recruitment of immune and inflammatory cells in the microenvironment of solid tumors is highly heterogeneous and follows patterns, varying according to the organ of origin and stage of disease, with critical roles in the process of cancer onset and progression. While adaptive cells are endowed with anti-tumor activities, inflammatory components of the immune infiltrate orchestrate an immunosuppressive microenvironment that reveals ambivalent functions of the immune contexture in the tumor milieu. The balance between opposing pro-tumoral and anti-tumoral immune pathways, which occur concomitantly in the tumor microenvironment, and the regulatory networks of these phenomena have been the target of several immunotherapeutic strategies. While the scarcity of adaptive immune effectors in tumors correlates with dismal prognosis, the pathways of activation of tumor-specific lymphocytes are yet to be fully elucidated. Recently, the occurrence of tertiary lymphoid tissue was revealed to be critical in mediating the dynamics of T cell recruitment and local activation of immune cells in the tumor microenvironment. Thus, tertiary lymphoid tissue assessment and targeting emerge as a promising approach for the design of novel prognostic immune signatures and immunotherapeutic strategies. The immunological behavior of tertiary lymphoid tissue, its occurrence in the tumor immune microenvironment and its clinical relevance are discussed here.

Immune-based therapies in pancreatic and colorectal cancers and biomarkers of responsiveness.

Immune-based strategies are the most promising treatments to improve cancer disease control. Early clinical trials are ongoing to test the safety and feasibility of immune-based therapies for gastrointestinal cancers. However, to date, immunotherapy has been only an experimental option for these diseases and a better understanding of their molecular, cellular, structural and clinical dissimilarities is crucial in the generation of tailored immunotherapeutic treatments. In this review, we will summarize the key mechanisms that regulate the action of immune system in cancer and the different immune-based approaches aimed at improving disease control in patients with advanced disease. We will then move on to discussing the current immunotherapeutic approaches in two types of gastrointestinal (colo-rectal and pancreatic) cancers, whose immune microenvironment has been lately object of intense analyses and has emerged as an important determinant of clinical outcome.