Changes in the local tumor microenvironment in recurrent cancers may explain the failure of vaccines after surgery. Proc Natl Acad Sci U S A. 2013;110:E415-E424. [PMID: 23271806 DOI: 10.1073/pnas.1211850110]

The Role of the Tumor Microenvironment in Developing Successful Therapeutic and Secondary Prophylactic Breast Cancer Vaccines

Breast cancer affects roughly one in eight women over their lifetime and is a leading cause of cancer-related death in women. While outcomes have improved in recent years, prognosis remains poor for patients who present with either disseminated disease or aggressive molecular subtypes. Cancer immunotherapy has revolutionized the treatment of several cancers, with therapeutic vaccines aiming to direct the cytotoxic immune program against tumor cells showing particular promise. However, these results have yet to translate to breast cancer, which remains largely refractory from such approaches. Recent evidence suggests that the breast tumor microenvironment (TME) is an important and long understudied barrier to the efficacy of therapeutic vaccines. Through an improved understanding of the complex and biologically diverse breast TME, it may be possible to advance new combination strategies to render breast carcinomas sensitive to the effects of therapeutic vaccines. Here, we discuss past and present efforts to advance therapeutic vaccines in the treatment of breast cancer, the molecular mechanisms through which the TME contributes to the failure of such approaches, as well as the potential means through which these can be overcome.

Tackling Resistance to Cancer Immunotherapy: What Do We Know?

Cancer treatment has evolved tremendously in the last few decades. Immunotherapy has been considered to be the forth pillar in cancer treatment in addition to conventional surgery, radiotherapy, and chemotherapy. Though immunotherapy has resulted in impressive response, it is generally limited to a small subset of patients. Understanding the mechanisms of resistance toward cancer immunotherapy may shed new light to counter that resistance. In this review, we highlighted and summarized two major hurdles (recognition and attack) of cancer elimination by the immune system. The mechanisms of failure of some available immunotherapy strategies were also described. Moreover, the significance role of immune compartment for various established cancer treatments were also elucidated in this review. Then, the mechanisms of combinatorial treatment of various conventional cancer treatment with immunotherapy were discussed. Finally, a strategy to improve immune cancer killing by characterizing cancer immune landscape, then devising treatment based on that cancer immune landscape was put forward.

Cell composition and expansion strategy can reduce the beneficial effect of AKT-inhibition on functionality of CD8+ T cells

AKT-inhibition is a promising approach to improve T cell therapies; however, its effect on CD4⁺ T cells is insufficiently explored. Previously, we and others showed that AKT-inhibition during ex vivo CD8⁺ T cell expansion facilitates the generation of polyfunctional T cells with stem cell memory-like traits. However, most therapeutic T cell products are generated from lymphocytes, containing CD4⁺ T cells that can affect CD8⁺ T cells dependent on the Th-subset. Here, we investigated the effect of AKT-inhibition on CD4⁺ T cells, during separate as well as total T cell expansions. Interestingly, ex vivo AKT-inhibition preserved the early memory phenotype of CD4⁺ T cells based on higher CD62L, CXCR4 and CCR7 expression. However, in the presence of AKT-inhibition, Th-differentiation was skewed toward more Th2-associated at the expense of Th1-associated cells. Importantly, the favorable effect of AKT-inhibition on the functionality of CD8⁺ T cells drastically diminished in the presence of CD4⁺ T cells. Moreover, also the expansion method influenced the effect of AKT-inhibition on CD8⁺ T cells. These findings indicate that the effect of AKT-inhibition on CD8⁺ T cells is dependent on cell composition and expansion strategy, where presence of CD4⁺ T cells as well as polyclonal stimulation impede the favorable effect of AKT-inhibition.

A Phase 1 Trial Assessing the Safety and Tolerability of a Therapeutic DNA Vaccination Against HPV16 and HPV18 E6/E7 Oncogenes After Chemoradiation for Cervical Cancer

PURPOSE

This study assessed the safety and tolerability of therapeutic immunization against the human papillomavirus (HPV) viral oncoproteins E6 and E7 in patients with cervical cancer after chemoradiation.

METHODS AND MATERIALS

MEDI0457 (INO-3112) is a DNA-based vaccine targeting E6 and E7 of HPV-16/18 that is coinjected with an IL-12 plasmid followed by electroporation with the CELLECTRA 5P device. At 2 to 4 weeks after chemoradiation, patients with newly diagnosed stage IB1-IVA (cohort 1) or persistent/recurrent (cohort 2) cervical cancers were treated with 4 immunizations of MEDI0457 every 4 weeks. The primary endpoints were incidence of adverse events and injection site reactions. Immune responses against HPV antigens were measured by ELISpot for interferon-γ (IFNγ), enzyme-linked immunosorbent assay for antibody responses and multiplexed immunofluorescence for immune cells in cervical biopsy specimens.

RESULTS

Ten patients (cohort 1, n = 7; cohort 2, n = 3) with HPV16 (n = 7) or HPV18 (n = 3) cervical cancers received MEDI0457 after chemoradiation. Treatment-related adverse events were all grade 1, primarily related to the injection site. Eight of 10 patients had detectable cellular or humoral immune responses against HPV antigens after chemoradiation and vaccination: 6 of 10 patients generated anti-HPV antibody responses and 6 of 10 patients generated IFNγ-producing T cell responses. At the completion of chemoradiation and vaccination, cervical biopsy specimens had detectable CD8⁺ T cells and decreased PD-1⁺CD8⁺, PD-L1⁺CD8⁺, and PD-L1⁺CD68⁺ subpopulations. All patients cleared detectable HPV DNA in cervical biopsies by completion of chemoradiation and vaccination.

CONCLUSIONS

Adjuvant MEDI0457 is safe and well tolerated after chemoradiation for locally advanced or recurrent cervical cancers, supporting further investigation into combining tumor-specific vaccines with radiation therapy.

Substantial tumor regression in prostate cancer patient with extensive skeletal metastases upon Immunotherapy (APCEDEN): A case report

RATIONALE

Prostate cancer along with colorectal and lung cancers accounts for 42% of cancer cases in men globally. It is the first cancer indication for which the use of active immunotherapy, Sipuleucel-T (Provenge) was granted by the FDA in 2010. This study presents a case of prostate carcinoma and the tumour remission observed after administration of a personalised Dendritic cell vaccine (APCEDEN).

PATIENT CONCERNS

A 58 years old Caucasian male diagnosed with prostate carcinoma with GLEASON score 8. The patient had previously been diagnosed with Renal Cell Carcinoma (RCC) in 1996 and had undergone nephrectomy of the right kidney. PET CT scan revealed multiple intensely PSMA avid lesions noted in both lobes of the prostate gland with SUVmax -28.3 and the prostate gland measuring 3.2 × 3.2 cm displaying maximum dimensions.

DIAGNOSIS

FNAC followed by PETCT confirmed CA Prostate and further supported by increased serum PSA level.

INTERVENTIONS

The patient underwent personalised Dendritic Cell Immunotherapy APCEDEN regimen of six doses biweekly, in a time frame of 3 months were given both via intravenous and intradermal route. Six months post completion of APCEDEN, the patient was administered 6 booster shots for 6 months.

OUTCOMES

Progressive remission of carcinoma was observed along with reduction in PSA and Testosterone levels. PET CT showed decline in PSMA avidity by 50% with SUVmax -14.0 and normal size and shape of prostate gland.

LESSONS

Prostate carcinoma is the second most common cancer in men with majority of them exhibiting locally advanced disease. Apparently 20% to 30% of them are categorized as relapsed cases after various therapeutic interventions. Modulating immune system is an emerging therapy termed as Immunotherapy and potentiates the killing cancer cells via immune activation. Interestingly, prostate cancer is slow growing and it provides the scope and time to mount an anti-tumor response which makes it an attractive target for immunotherapy. This case study demonstrates the efficacy of APCEDEN Immunotherapy regimen resulting in a significant disease remission benefiting the patient.

Targeting the Tumor Microenvironment in Colorectal Peritoneal Metastases

Peritoneal metastasis (PM) occurs in approximately one in four colorectal cancer (CRC) patients. The pathophysiology of colorectal PM remains poorly characterized. Also, the efficacy of current treatment modalities, including surgery and intraperitoneal (IP) delivery of chemotherapy, is limited. Increasingly, therefore, efforts are being developed to unravel the PM cascade and at understanding the PM-associated tumor microenvironment (TME) and peritoneal ecosystem as potential therapeutic targets. Here, we review recent insights in the structure and components of the TME in colorectal PM, and discuss how these may translate into novel therapeutic approaches aimed at re-engineering the metastasis-promoting activity of the stroma.

The pro-tumorigenic host response to cancer therapies

Resistance to cancer therapy remains a major challenge in clinical oncology. Although the initial treatment phase is often successful, eventual resistance, characterized by tumour relapse or spread, is discouraging. The majority of studies devoted to investigating the basis of resistance have focused on tumour-related changes that contribute to therapy resistance and tumour aggressiveness. However, over the last decade, the diverse roles of various host cells in promoting therapy resistance have become more appreciated. A growing body of evidence demonstrates that cancer therapy can induce host-mediated local and systemic responses, many of which shift the delicate balance within the tumour microenvironment, ultimately facilitating or supporting tumour progression. In this Review, recent advances in understanding how the host response to different cancer therapies may promote therapy resistance are discussed, with a focus on therapy-induced immunological, angiogenic and metastatic effects. Also summarized is the potential of evaluating the host response to cancer therapy in an era of precision medicine in oncology.

Blocking TGF-β Signaling To Enhance The Efficacy Of Immune Checkpoint Inhibitor

During malignant transformation, a growing body of mutations accumulate in cancer cells which not only drive cancer progression but also endow cancer cells with high immunogenicity. However, because one or multiple steps in cancer-immunity cycle are impaired, anti-cancer immune response is too weak to effectively clear cancer cells. Therefore, how to restore robust immune response to malignant cells is a hot research topic in cancer therapeutics field. In the last decade, based on the deeper understanding of cancer immunity, great signs of progress have been made in cancer immunotherapies especially immune checkpoint inhibitors (ICIs). ICIs could block negative immune co-stimulatory pathways and reactivate tumor-infiltrating lymphocytes (TILs) from exhausted status. ICIs exhibit potent anti-cancer effect and have been approved for the treatment of numerous cancer types. Parallel with durable and effective tumor control, the actual response rate of ICIs is unsatisfactory. Although a subset of patients benefit from ICIs treatment, a large proportion of patients show primary or acquired resistance. Previously intensive studies indicated that the efficacy of ICIs was determined by a series of factors including tumor mutation burden, programmed death ligand-1 (PD-L1) expression, and TILs status. Recently, it was reported that transforming growth factor-beta (TGF-β) signaling pathway participated in cancer immune escape and ICI resistance. Concurrent TGF-β blockade might be a feasible strategy to enhance the efficacy of immunotherapy and relieve ICI resistance. In this mini-review, we summarized the latest understanding of TGF-β signaling pathway and cancer immunity. Besides, we highlighted the synergistic effect of TGF-β blockade and ICIs.

A Designer Scaffold with Immune Nanoconverters for Reverting Immunosuppression and Enhancing Immune Checkpoint Blockade Therapy

Current cancer immunotherapy based on immune checkpoint blockade (ICB) still suffers from low response rate and systemic toxicity. To overcome the limitation, a novel therapeutic platform that can revert nonimmunogenic tumors into immunogenic phenotype is highly required. Herein, a designer scaffold loaded with both immune nanoconverters encapsulated with resiquimod (iNCVs (R848)) and doxorubicin, which provides the polarization of immunosuppressive tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) into tumoricidal antigen-presenting cells (APCs), rather than depleting them, as well as in situ vaccination that can be generated in vivo without the need to previously analyze and sequence tumor antigens to favor neoantigen-specific T cell responses is suggested. Local and sustained release of iNCVs (R848) and doxorubicin from the designer scaffold not only reduces the frequency of immunosuppressive cells in tumors but also increases systemic antitumor immune response, while minimizing systemic toxicity. Reshaping the tumor microenivronment (TME) using the designer-scaffold-induced synergistic antitumor immunity with ICB effects and long-term central and effector memory T cell responses, results in the prevention of postsurgical tumor recurrence and metastasis. The spatiotemporal modulation of TMEs through designer scaffolds is expected to be a strategy to overcome the limitations and improve the therapeutic efficacy of current immunotherapies with minimized systemic toxicity.

Improving cancer immunotherapy through nanotechnology

The 2018 Nobel Prize in Physiology or Medicine was awarded to pioneers in the field of cancer immunotherapy, as the utility of leveraging a patient's coordinated and adaptive immune system to fight the patient's unique tumour has now been validated robustly in the clinic. Still, the proportion of patients who respond to immunotherapy remains modest (~15% objective response rate across indications), as tumours have multiple means of immune evasion. The immune system is spatiotemporally controlled, so therapies that influence the immune system should be spatiotemporally controlled as well, in order to maximize the therapeutic index. Nanoparticles and biomaterials enable one to program the location, pharmacokinetics and co-delivery of immunomodulatory compounds, eliciting responses that cannot be achieved upon administration of such compounds in solution. The convergence of cancer immunotherapy, nanotechnology, bioengineering and drug delivery is opportune, as each of these fields has matured independently to the point that it can now be used to complement the others substantively and rationally, rather than modestly and empirically. As a result, unmet needs increasingly can be addressed with deductive intention. This Review explores how nanotechnology and related approaches are being applied to augmenting both endogenous leukocytes and adoptively transferred ones by informing specificity, influencing localization and improving function.

Syringeable immunotherapeutic nanogel reshapes tumor microenvironment and prevents tumor metastasis and recurrence

The low response rate of current cancer immunotherapy suggests the presence of few antigen-specific T cells and a high number of immunosuppressive factors in tumor microenvironment (TME). Here, we develop a syringeable immunomodulatory multidomain nanogel (iGel) that overcomes the limitation by reprogramming of the pro-tumoral TME to antitumoral immune niches. Local and extended release of immunomodulatory drugs from iGel deplete immunosuppressive cells, while inducing immunogenic cell death and increased immunogenicity. When iGel is applied as a local postsurgical treatment, both systemic antitumor immunity and a memory T cell response are generated, and the recurrence and metastasis of tumors to lungs and other organs are significantly inhibited. Reshaping of the TME using iGel also reverts non-responding groups to checkpoint blockade therapies into responding groups. The iGel is expected as an immunotherapeutic platform that can reshape immunosuppressive TMEs and synergize cancer immunotherapy with checkpoint therapies, with minimized systemic toxicity.

The limited efficacy of current immunotherapy suggests low antigen-specific T cells and immunosuppressive factors in tumor microenvironment (TME). Here, the authors develop a syringeable immunomodulatory multi-domain nanogel that can reprogram the TME and induce enhanced cancer immunotherapy.

Nanoengineered Immune Niches for Reprogramming the Immunosuppressive Tumor Microenvironment and Enhancing Cancer Immunotherapy

Cancer immunotherapies that harness the body's immune system to combat tumors have received extensive attention and become mainstream strategies for treating cancer. Despite promising results, some problems remain, such as the limited patient response rate and the emergence of severe immune-related adverse effects. For most patients, the therapeutic efficacy of cancer immunotherapy is mainly limited by the immunosuppressive tumor microenvironment (TME). To overcome such obstacles in the TME, the immunomodulation of immunosuppressive factors and therapeutic immune cells (e.g., T cells and antigen-presenting cells) should be carefully designed and evaluated. Nanoengineered synthetic immune niches have emerged as highly customizable platforms with a potent capability for reprogramming the immunosuppressive TME. Here, recent developments in nano-biomaterials that are rationally designed to modulate the immunosuppressive TME in a spatiotemporal manner for enhanced cancer immunotherapy which are rationally designed to modulate the immunosuppressive TME in a spatiotemporal manner for enhanced cancer immunotherapy are highlighted.

Evaluation of Aminolevulinic Acid-Derived Tumor Fluorescence Yields Disparate Results in Murine and Spontaneous Large Animal Models of Lung Cancer

Fluorescence guided surgery is an emerging technology that may improve accuracy of pulmonary resection for non-small cell lung cancer (NSCLC). Herein we explore optical imaging for NSCLC surgery using the well-studied protoporphyrin IX (PPIX)/5-aminiolevulinic acid (5-ALA) system. More specifically, we evaluate fluorescent patterns observed when using (1) commonly utilized in vitro and murine NSCLC models and with (2) spontaneous canine NSCLCs, which closely mimic human disease. Using flow cytometry and fluorescent microscopy, we confirmed that NSCLC models fluoresce after exposure to 5-ALA in vitro. High levels of fluorescence were similarly observed in murine tumors within 2 hours of systemic 5-ALA delivery. When evaluating this approach in spontaneous canine NSCLC, tumor fluorescence was observed in 6 of 7 canines. Tumor fluorescence, however, was heterogenous owing to intratumoral variations in cellularity and necrosis. Margin and lymph node detection was inaccurate. These data demonstrate the importance of incorporating reliable cancer models into preclinical evaluations of optical agents. Utilization of spontaneous large animal models of cancer may further provide an important intermediate in the path to human translation of optical contrast agents.

Mature neutrophils suppress T cell immunity in ovarian cancer microenvironment

Epithelial ovarian cancer (EOC) often presents with metastases and ascites. Granulocytic myeloid-derived suppressor cells are an immature population that impairs antitumor immunity. Since suppressive granulocytes in the ascites of patients with newly diagnosed EOC were morphologically mature, we hypothesized that PMN were rendered suppressive in the tumor microenvironment (TME). Circulating PMN from patients were not suppressive but acquired a suppressor phenotype (defined as ≥1 log10 reduction of anti-CD3/CD28-stimulated T cell proliferation) after ascites supernatant exposure. Ascites supernatants (20 of 31 supernatants) recapitulated the suppressor phenotype in PMN from healthy donors. T cell proliferation was restored with ascites removal and restimulation. PMN suppressors also inhibited T cell activation and cytokine production. PMN suppressors completely suppressed proliferation in naive, central memory, and effector memory T cells and in engineered tumor antigen-specific cytotoxic T lymphocytes, while antigen-specific cell lysis was unaffected. Inhibition of complement C3 activation and PMN effector functions, including CR3 signaling, protein synthesis, and vesicular trafficking, abrogated the PMN suppressor phenotype. Moreover, malignant effusions from patients with various metastatic cancers also induced the C3-dependent PMN suppressor phenotype. These results point to PMN impairing T cell expansion and activation in the TME and the potential for complement inhibition to abrogate this barrier to antitumor immunity.

Antigen delivery targeted to tumor-associated macrophages overcomes tumor immune resistance

Immune checkpoint inhibitors and adoptive transfer of gene-engineered T cells have emerged as novel therapeutic modalities for hard-to-treat solid tumors; however, many patients are refractory to these immunotherapies, and the mechanisms underlying tumor immune resistance have not been fully elucidated. By comparing the tumor microenvironment of checkpoint inhibition-sensitive and -resistant murine solid tumors, we observed that the resistant tumors had low immunogenicity. We identified antigen presentation by CD11b+F4/80+ tumor-associated macrophages (TAMs) as a key factor correlated with immune resistance. In the resistant tumors, TAMs remained inactive and did not exert antigen-presenting activity. Targeted delivery of a long peptide antigen to TAMs by using a nano-sized hydrogel (nanogel) in the presence of a TLR agonist activated TAMs, induced their antigen-presenting activity, and thereby transformed the resistant tumors into tumors sensitive to adaptive immune responses such as adoptive transfer of tumor-specific T cell receptor-engineered T cells. These results indicate that the status and function of TAMs have a significant impact on tumor immune sensitivity and that manipulation of TAM functions would be an effective approach for improving the efficacy of immunotherapies.

Prospects and challenges of immunotherapy for pancreatic cancer

Pancreatic cancer is a highly malignant digestive system tumor with an extremely poor prognosis. It has been reported that pancreatic cancer has now surpassed breast cancer as the third leading cause of cancer death in the United States. Due to its low early diagnosis rate, most patients have lost the chance of surgery at the time of diagnosis. However, various treatment strategies (like radiotherapy, chemotherapy, targeted therapy, etc.) have not been able to significantly improve their survival rate. A large body of evidence suggests that an important cause of high lethality in pancreatic cancer is the immune privilege of tumors driven by factors such as immunosuppressive microenvironment, low T cell infiltration, and low gene mutation load. In recent years, tumor immunotherapy has become a hot spot in the field of oncology, and significant progress has been made in the treatment of pancreatic cancer. At present, various new immunotherapies such as immunological checkpoint blockers, adoptive cell therapy, and tumor vaccine have entered the clinical or preclinical stage, and all of them have hope to become a new treatment strategy to improve the treatment of patients with pancreatic cancer. Here, we briefly summarize the recent advances in immunotherapy for pancreatic cancer that is being researched and promising in recent years, as well as the challenges and prospects, with an aim to open up new horizons for the development of new and effective immunotherapy for pancreatic tumors.

Ovarian cancer stem cells: What progress have we made?

Ovarian cancer (OvCa) is the most lethal gynecological malignancy in the United States primarily due to lack of a reliable early diagnostic, high incidence of chemo-resistant recurrent disease as well as profuse tumor heterogeneity. Cancer stem cells (CSCs) continue to gain attention, as they are known to resist chemotherapy, self-renew and re-populate the bulk tumor with undifferentiated and differentiated cells. Moreover, CSCs appear to readily adapt to environmental, immunologic and pharmacologic cues. The plasticity and ability to inactivate or activate signaling pathways promoting their longevity has been, and continues to be, the challenge faced in developing successful CSC targeted therapies. Identifying and understanding unique ovarian CSC markers and the pathways they utilize could reveal new therapeutic opportunities that may offer alternative adjuvant treatment options. Herein, we will discuss the current state of ovarian CSC characterization, their contribution to disease resistance, recurrence and shed light on clinical trials that may target the CSC population.

A curative treatment strategy using tumor debulking surgery combined with immune checkpoint inhibitors for advanced pediatric solid tumors: An in vivo study using a murine model of osteosarcoma

BACKGROUND/PURPOSE

This study aimed to assess the significance of tumor debulking surgery by using immune checkpoint inhibitors for advanced pediatric solid tumors in a murine model of advanced osteosarcoma.

METHODS

In C3H mice, 5 × 10⁶ LM8 (osteosarcoma cell line with a high metastatic potential in the lungs originating from the C3H mouse) cells were transplanted subcutaneously. Thereafter, the mice were divided into 4 groups as follows: the control group received no intervention (CG, n = 5), the surgery group underwent subcutaneous tumor resection (tumor debulking surgery) 11 days after transplantation (SG, n = 10), the immunotherapy group received a cocktail consisting of 200 μg each of three antibodies (anti-Tim-3, anti-PD-L1, and anti-OX-86) intraperitoneally on posttransplantation days 11, 14, 18, and 21 (IG, n = 10), and the combination therapy group, tumor debulking surgery on day 11 and the cocktail intraperitoneally on days 11, 14, 18, and 21 (COMBG, n = 10). Survival curves were plotted by using the Kaplan-Meier method and compared with those plotted using the log-rank test. Next, the lungs of mice in the 4 groups were pathologically evaluated.

RESULTS

The COMBG showed significantly longer survival than the other three groups (P ≤ 0.002), whereas the SG and IG revealed no difference in survival rate compared to CG. Pathological evaluations revealed no lung metastasis 16 weeks after tumor transplantation in the survivors of COMBG.

CONCLUSIONS

The results of this study suggest that tumor debulking surgery combined with immune checkpoint inhibitors could be a curative treatment for advanced pediatric solid tumors.

Immunotherapy and Prevention of Pancreatic Cancer

Pancreatic cancer is the third-leading cause of cancer mortality in the USA, recently surpassing breast cancer. A key component of pancreatic cancer's lethality is its acquired immune privilege, which is driven by an immunosuppressive microenvironment, poor T cell infiltration, and a low mutational burden. Although immunotherapies such as checkpoint blockade or engineered T cells have yet to demonstrate efficacy, a growing body of evidence suggests that orthogonal combinations of these and other strategies could unlock immunotherapy in pancreatic cancer. In this Review article, we discuss promising immunotherapies currently under investigation in pancreatic cancer and provide a roadmap for the development of prevention vaccines for this and other cancers.

Potential impact of invasive surgical procedures on primary tumor growth and metastasis

Surgical procedures such as tumor resection and biopsy are still the gold standard for diagnosis and (determination of) treatment of solid tumors, and are prognostically beneficial for patients. However, growing evidence suggests that even a minor surgical trauma can influence several (patho) physiological processes that might promote postoperative metastatic spread and tumor recurrence. Local effects include tumor seeding and a wound healing response that can promote tumor cell migration, proliferation, differentiation, extracellular matrix remodeling, angiogenesis and extravasation. In addition, local and systemic immunosuppression impairs antitumor immunity and contributes to tumor cell survival. Surgical manipulation of the tumor can result in cancer cell release into the circulation, thus increasing the chance of tumor cell dissemination. To prevent these undesired effects of surgical interventions, therapeutic strategies targeting immune response exacerbation or alteration have been proposed. This review summarizes the current literature regarding these local, systemic and secondary site effects of surgical interventions on tumor progression and dissemination, and discusses studies that aimed to identify potential therapeutic approaches to prevent these effects in order to further increase the clinical benefit from surgical procedures.

Systemic inflammatory status predict the outcome of k-RAS WT metastatic colorectal cancer patients receiving the thymidylate synthase poly-epitope-peptide anticancer vaccine

TSPP is an anticancer poly-epitope peptide vaccine to thymidylate synthase, recently investigated in the multi-arm phase Ib TSPP/VAC1 trial. TSPP vaccination induced immune-biological effects and showed antitumor activity in metastatic colorectal cancer (mCRC) patients and other malignancies. Progression-free and overall survival of 41 mCRC patients enrolled in the study correlated with baseline levels of CEA, immune-inflammatory markers (neutrophil/lymphocyte ratio, CRP, ESR, LDH, ENA), IL-4 and with post-treatment change in p-ANCA and CD56^dimCD16^brightNKs (p < 0.04). A subset of 19 patients with activating k-ras mutations showed a different immune-inflammatory response to TSPP as compared to patients with k-ras/wt and a worse outcome in term of PFS (p = 0.048). In patients with k-ras/mut, inflammatory markers lost their predictive value and their survival directly correlated with the baseline levels of IL17/A over the median value (p = 0.01). These results provide strong hints for the design of further clinical trials aimed to test TSPP vaccination in mCRC patients.

Epigenetic control of macrophage polarization: implications for targeting tumor-associated macrophages

The progression of cancer is a result of not only the growth of the malignant cells but also the behavior of other components of the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are key components of the TME that influence tumor growth and disease progression. TAMs can either inhibit or support tumor growth depending on their polarization to classically-activated macrophages (M1s) or alternatively-activated macrophages (M2s), respectively. Epigenetic regulation plays a significant role in determining this polarization and manipulating the epigenetic regulation in macrophages would provide a means for selectively targeting M2s thereby eliminating tumor-supporting TAMs while sparing tumor-inhibiting M1 TAMs. Many pharmacologic modulators of epigenetic enzymes are currently used clinically and could be repurposed for treating tumors with high TAM infiltrate. While much research involving epigenetic enzymes and their modulators has been performed in M1s, significantly less is known about the epigenetic regulation of M2s. This review highlights the field’s current knowledge of key epigenetic enzymes and their pharmacologic modulators known to influence macrophage polarization.

Precision Immuno-Oncology: Prospects of Individualized Immunotherapy for Pancreatic Cancer

Pancreatic cancer, most commonly referring to pancreatic ductal adenocarcinoma (PDAC), remains one of the most deadly diseases, with very few effective therapies available. Emerging as a new modality of modern cancer treatments, immunotherapy has shown promises for various cancer types. Over the past decades, the potential of immunotherapy in eliciting clinical benefits in pancreatic cancer have also been extensively explored. It has been demonstrated in preclinical studies and early phase clinical trials that cancer vaccines were effective in eliciting anti-tumor immune response, but few have led to a significant improvement in survival. Despite the fact that immunotherapy with checkpoint blockade (e.g., anti-cytotoxic T-lymphocyte antigen 4 [CTLA-4] and anti-programmed cell death 1 [PD-1]/PD-L1 antibodies) has shown remarkable and durable responses in various cancer types, the application of checkpoint inhibitors in pancreatic cancer has been disappointing so far. It may, in part, due to the unique tumor microenvironment (TME) of pancreatic cancer, such as existence of excessive stromal matrix and hypovascularity, creating a TME of strong inhibitory signaling circuits and tremendous physical barriers for immune agent infiltration. This informs on the need for combination therapy approaches to engender a potent immune response that can translate to clinical benefits. On the other hand, lack of effective and validated biomarkers to stratify subgroup of patients who can benefit from immunotherapy poses further challenges for the realization of precision immune-oncology. Future studies addressing issues such as TME modulation, biomarker identification and therapeutic combination are warranted. In this review, advances in immunotherapy for pancreatic cancer were discussed and opportunities as well as challenges for personalized immune-oncology were addressed.

Activated dendritic cells delivered in tissue compatible biomatrices induce in-situ anti-tumor CTL responses leading to tumor regression

Dendritic cell (DC) based anti-cancer immunotherapy is well tolerated in patients with advanced cancers. However, the clinical responses seen after adoptive DC therapy have been suboptimal. Several factors including scarce DC numbers in tumors and immunosuppressive tumor microenvironments contribute to the inefficacy of DCs as cellular vaccines. Hence DC based vaccines can benefit from novel methods of cell delivery that would prevent the direct exposure of immune cells to suppressive tumor microenvironments. Here we evaluated the ability of DCs harbored in biocompatible scaffolds (referred to as biomatrix entrapped DCs; beDCs) in activating specific anti-tumor immune responses against primary and post-surgery secondary tumors. Using a preclinical cervical cancer and a melanoma model in mice, we show that single treatment of primary and post-surgery secondary tumors using beDCs resulted in significant tumor growth retardation while multiple inoculations were required to achieve a significant anti-tumor effect when DCs were given in free form. Additionally, we found that, compared to the tumor specific E6/E7 peptide vaccine, total tumor lysate induced higher expression of CD80 and CD40 on DCs that induced increased levels of IFNγ production upon interaction with host lymphocytes. Remarkably, a strong immunocyte infiltration into the host-implanted DC-scaffold was observed. Importantly, the host-implanted beDCs induced the anti-tumor immune responses in the absence of any stromal cell support, and the biomatrix structure was eventually absorbed into the surrounding host tissue. Collectively, these data indicate that the scaffold-based DC delivery may provide an efficient and safe way of delivering cell-based vaccines for treatment of primary and post-surgery secondary tumors.

Intraoperative Near-Infrared Optical Imaging Can Localize Gadolinium-Enhancing Gliomas During Surgery

BACKGROUND

Although real-time localization of gliomas has improved with intraoperative image guidance systems, these tools are limited by brain shift, surgical cavity deformation, and expense.

OBJECTIVE

To propose a novel method to perform near-infrared (NIR) imaging during glioma resections based on preclinical and clinical investigations, in order to localize tumors and to potentially identify residual disease.

METHODS

Fifteen patients were identified and administered a Food and Drug Administration-approved, NIR contrast agent (Second Window indocyanine green [ICG], 5 mg/kg) before surgical resection. An NIR camera was utilized to localize the tumor before resection and to visualize surgical margins following resection. Neuropathology and magnetic resonance imaging data were used to assess the accuracy and precision of NIR fluorescence in identifying tumor tissue.

RESULTS

NIR visualization of 15 gliomas (10 glioblastoma multiforme, 1 anaplastic astrocytoma, 2 low-grade astrocytoma, 1 juvenile pilocytic astrocytoma, and 1 ganglioglioma) was performed 22.7 hours (mean) after intravenous injection of ICG. During surgery, 12 of 15 tumors were visualized with the NIR camera. The mean signal-to-background ratio was 9.5 ± 0.8 and fluorescence was noted through the dura to a maximum parenchymal depth of 13 mm. The best predictor of positive fluorescence was enhancement on T1-weighted imaging; this correlated with signal-to-background ratio (P = .03). Nonenhancing tumors did not demonstrate NIR fluorescence. Using pathology as the gold standard, the technique demonstrated a sensitivity of 98% and specificity of 45% to identify tumor in gadolinium-enhancing specimens (n = 71).

CONCLUSION

With the use of Second Window ICG, gadolinium-enhancing tumors can be localized through brain parenchyma intraoperatively. Its utility for margin detection is promising but limited by lower specificity.

ABBREVIATIONS

5-ALA, 5-aminolevulinic acidEPR, enhanced permeability and retentionFDA, Food and Drug AdministrationGBM, glioblastomaICG, indocyanine greenNIR, near-infraredNPV, negative predictive valuePPV, positive predictive valueROC, receiver operating characteristicROI, region of interestSBR, signal-to-background ratioWHO, World Health Organization.

Intraoperative Near-Infrared Optical Contrast Can Localize Brain Metastases

INTRODUCTION

Approximately 100,000 brain metastases are diagnosed annually in the United States. Our laboratory has pioneered a novel technique, second window indocyanine green (SWIG), which allows for real-time intraoperative visualization of brain metastasis through normal brain parenchyma and intact dura.

METHODS

Thirteen patients with intraparenchymal brain metastases were administered indocyanine green (ICG) at 5 mg/kg the day before surgery. A near-infrared (NIR)- capable camera was used intraoperatively to identify the tumor and to inspect surgical margins. Neuropathology was used to assess the accuracy and precision of the fluorescent dye for identifying tumor.

RESULTS

ICG was infused at 24.7 ± 3.45 hours before visualization. All 13 metastases fluoresced with an average signal-to-background ratio (SBR) of 6.62. The SBR with the dura intact was 67.2% of the mean SBR once the dura was opened. The NIR signal could be visualized through normal brain parenchyma up to 7 mm. For the 39 total specimens, the mean SBR for tumor specimens (n = 28) was 6.9, whereas the SBR for nontumor specimens (n = 11) was 3.7. The sensitivity, specificity, positive predictive value, and negative predictive value of NIR imaging for tumor was 96.4%, 27.3%, 77.1%, and 75.0%.

DISCUSSION

SWIG relies on the passive accumulation of dye in abnormal tumor tissue via the enhanced permeability and retention effect. It provides strong NIR optical contrast, which can be used to localize tumors before dural opening. The use of SWIG for margin assessment remains limited by its lack of specificity (high false-positive rate); however, ongoing improvements in imaging parameters show great potential to reduce false-positive results.

Anti-cancer activity of dose-fractioned mPE +/- bevacizumab regimen is paralleled by immune-modulation in advanced squamous NSLC patients

Background

Results from the BEVA2007 trial, suggest that the metronomic chemotherapy regimen with dose-fractioned cisplatin and oral etoposide (mPE) +/- bevacizumab, a monoclonal antibody to the vascular endothelial growth factor (VEGF), shows anti-angiogenic and immunological effects and is a safe and active treatment for metastatic non-small cell lung cancer (mNSCLC) patients. We carried out a retrospective analysis aimed to evaluate the antitumor effects of this treatment in a subset of patients with squamous histology.

Methods

Retrospective analysis was carried out in a subset of 31 patients with squamous histology enrolled in the study between September 2007 and September 2015. All of the patients received chemotherapy with cisplatin (30 mg/sqm, days 1-3q21) and oral etoposide (50 mg, days 1-15q21) (mPE) and 14 of them also received bevacizumab 5 mg/kg on the day 3q21 (mPEBev regimen).

Results

This treatment showed a disease control rate of 71% with a mean progression free survival (PFS) and overall survival (OS) of 13.6 and 17 months respectively. After 4 treatment courses, 6 patients showing a remarkable tumor shrinkage, underwent to radical surgery, attaining a significant advantage in term of survival (P=0.048). Kaplan-Meier and log-rank test identified the longest survival in patients presenting low baseline levels in neutrophil-to-lymphocyte ratio (NLR) (P=0.05), interleukin (IL) 17A (P=0.036), regulatory-T-cells (T_regs) (P=0.020), and activated CD83+ dendritic cells (DCs) (P=0.03).

Conclusions

These results suggest that the mPE +/- bevacizumab regimen is feasible and should be tested in comparative trials in advanced squamous-NSCLC (sqNSCLC). Moreover, its immune-biological effects strongly suggest the investigation in sequential combinations with immune check-point inhibitors.

PD-1/PD-L1 and immunotherapy for pancreatic cancer

Therapy that targets programmed death 1 or programmed death 1 ligand 1 (PD-1/PD-L1), which are known as immune checkpoints, has been recently rapidly developing as oncotherapy for various carcinomas. However, this therapy has a poor effect on the treatment of pancreatic cancer with PD-1/PD-L1 blockade monotherapy. In this review, the development and limitations of anti-PD-1/PD-L1 monotherapy in pancreatic cancer are discussed. We then consider the underlying mechanism of anti-PD-1/PD-L1 monotherapy failure, combination strategies overcoming resistance to anti-PD-1/PD-L1 immunotherapy and the prospect of targeting PD-1/PD-L1 for the immunotherapy of pancreatic cancer.

Preventing inflammation inhibits biopsy-mediated changes in tumor cell behavior

Although biopsies and tumor resection are prognostically beneficial for glioblastomas (GBM), potential negative effects have also been suggested. Here, using retrospective study of patients and intravital imaging of mice, we identify some of these negative aspects, including stimulation of proliferation and migration of non-resected tumor cells, and provide a strategy to prevent these adverse effects. By repeated high-resolution intravital microscopy, we show that biopsy-like injury in GBM induces migration and proliferation of tumor cells through chemokine (C-C motif) ligand 2 (CCL-2)-dependent recruitment of macrophages. Blocking macrophage recruitment or administrating dexamethasone, a commonly used glucocorticoid to prevent brain edema in GBM patients, suppressed the observed inflammatory response and subsequent tumor growth upon biopsy both in mice and in multifocal GBM patients. Taken together, our study suggests that inhibiting CCL-2-dependent recruitment of macrophages may further increase the clinical benefits from surgical and biopsy procedures.

Immune checkpoint inhibitors renal side effects and management

The choice of immunotherapy in the treatment of cancer has improved the prognosis of many patients affected by various malignancies. The high expectations foreseen with immunotherapy have led to fast approvals despite the incomplete understanding of the toxicity profiles in the different organs, including the kidneys. The high prevalence of chronic kidney disease in cancer patients complicates the issue further and requires a better knowledge of the renal safety profile to ensure an optimal safe treatment. This review summarizes the present knowledge of renal adverse events secondary to immune checkpoint inhibitors and discusses their pathophysiology, clinical presentation and adequate management. We also advocate the need for a multidisciplinary approach in patients with immune-related toxic adverse events.

Immunotherapies in sarcoma: Updates and future perspectives

Sarcomas are malignant tumors that are characterized by a wide diversity of subtypes with various cytogenetic profiles. Despite major treatment breakthroughs, standard treatment modalities combining chemotherapy, radiotherapy, and surgery failed to improve overall survival. Therefore, high expectations are foreseen with immunotherapy upon its maturation and better understanding of its mechanism of action. This paper presents a targeted review of the published data and ongoing clinical trials in immunotherapies of sarcomas, mainly adoptive cell therapies, cancer vaccines and immune checkpoint inhibitors.

A comprehensive review of immunotherapies in prostate cancer

Prostate cancer is the second most common malignant neoplasm in men worldwide and the fifth cause of cancer-related death. Although multiple new agents have been approved for metastatic castration resistant prostate cancer over the last decade, it is still an incurable disease. New strategies to improve cancer control are needed and agents targeting the immune system have shown encouraging results in many tumor types. Despite being attractive for immunotherapies due to the expression of various tumor associated antigens, the microenvironment in prostate cancer is relatively immunosuppressive and may be responsible for the failures of various agents targeting the immune system in this disease. To date, sipuleucel-T is the only immunotherapy that has shown significant clinical efficacy in this setting, although the high cost and potential trial flaws have precluded its widespread incorporation into clinical practice. Issues with patient selection and trial design may have contributed to the multiple failures of immunotherapy in prostate cancer and provides an opportunity to tailor future studies to evaluate these agents more accurately. We have reviewed all the completed immune therapy trials in prostate cancer and highlight important considerations for the next generation of clinical trials.

Intraoperative imaging identifies thymoma margins following neoadjuvant chemotherapy

Near infrared (NIR) molecular imaging is useful to identify tumor margins during surgery; however, the value of this technology has not been evaluated for tumors that have been pre-treated with chemotherapy. We hypothesized that NIR molecular imaging could locate mediastinal tumor margins in a murine model after neoadjuvant chemotherapy. Flank thymomas were established on mice. Two separate experiments were performed for tumor margin detection. The first experiment compared (i) surgery and (ii) surgery + NIR imaging. The second experiment compared (iii) preoperative chemotherapy + surgery, and (iv) preoperative chemotherapy + surgery + NIR imaging. NIR imaging occurred following systemic injection of indocyanine green. Margins were assessed for residual tumor cells by pathology. NIR imaging was superior at detecting retained tumor cells during surgery compared to standard techniques (surgery alone vs. surgery + NIR imaging, 20% vs. 80%, respectively). Following chemotherapy, the sensitivity of NIR imaging of tumor margins was not significantly altered. The mean in vivo tumor-to-background fluorescence ratio was similar in the treatment-naïve and chemotherapy groups ((p = 0.899): 3.79 ± 0.69 (IQR 3.29 - 4.25) vs. 3.79 ± 0.52 (IQR 3.40 - 4.03)). We conclude that chemotherapy does not affect tumor fluorescence or identification of retained cancer cells at margins.

Chloroquine (CQ) exerts anti-breast cancer through modulating microenvironment and inducing apoptosis

CQ is an anti-malaria drug, which has been used for years. However, there are published articles about its activity in anti-cancers. The aim of this approach was to look at possibility and related mechanisms of anti-breast cancer (mouse breast cancer cell line 4T1) by CQ alone. The studies of anti 4T1 in vitro and in vivo by CQ were performed. The growth of 4T1 in vitro and in vivo, survival of mice post treatment with CQ, changes of immune parameters and microenvironment in mice were evaluated. Our results demonstrate that CQ could markedly inhibit growth of 4T1 in vitro through inducing apoptosis of cells, inhibiting secretion of TGF-β and prolong the mice survival in vivo through boosting immune system by upregulating CD8+ T cell, and through down-regulating tumor associated macrophages (TAM), myeloid derived suppressing cells (MDSC) and Tregs, in microenvironment of mice bearing tumor. This provides a new mode of action for CQ and it is therefore concluded that CQ could be with potential in breast cancer therapy.

Treg cells as potential cellular targets for functionalized nanoparticles in cancer therapy

Treg cell-mediated immune suppression appears to represent a significant barrier to effective anticancer immune responses and their inactivation or removal is viewed as a potential therapeutic approach. Although suitable tools for selective Treg cell manipulation in man are missing, their number and function can be altered by a number of drugs and biologicals and by reprogramming tumor-infiltrating antigen presenting cells. Nanoparticles offer exceptional new options in drug and gene delivery by prolonging the circulation time of their cargo, protecting it from degradation and promoting its local accumulation in cells and tissues. In tumor therapy, the use of nanoparticles is expected to overcome limitations in drug delivery and provide novel means for cell-specific functional alteration. In this perspective, we summarize strategies suitable for interference with Treg-mediated suppression, discuss the potential use of nanoparticles for this purpose and identify additional, unexplored opportunities.

Interleukin-17-Producing Neutrophils Link Inflammatory Stimuli to Disease Progression by Promoting Angiogenesis in Gastric Cancer

Purpose: Elevated levels of neutrophils have been associated with poor survival in various cancers, but direct evidence supporting a role for neutrophils in the immunopathogenesis of human cancers is lacking.Experimental Design: A total of 573 patients with gastric cancer were enrolled in this study. Immunohistochemistry and real-time PCR were performed to analyze the distribution and clinical relevance of neutrophils in different microanatomic regions. The regulation and function of neutrophils were assessed both in vitro and in vivoResults: Increased neutrophil counts in the peripheral blood were associated with poor prognosis in gastric cancer patients. In gastric cancer tissues, neutrophils were enriched predominantly in the invasive margin, and neutrophil levels were a powerful predictor of poor survival in patients with gastric cancer. IL17⁺ neutrophils constitute a large portion of IL17-producing cells in human gastric cancer. Proinflammatory IL17 is a critical mediator of the recruitment of neutrophils into the invasive margin by CXC chemokines. Moreover, neutrophils at the invasive margin were a major source of matrix metalloproteinase-9, a secreted protein that stimulates proangiogenic activity in gastric cancer cells. Accordingly, high levels of infiltrated neutrophils at the invasive margin were positively correlated with angiogenesis progression in patients with gastric cancer.Conclusions: These data provide direct evidence supporting the pivotal role of neutrophils in gastric cancer progression and reveal a novel immune escape mechanism involving fine-tuned collaborative action between cancer cells and immune cells in the distinct tumor microenvironment. Clin Cancer Res; 23(6); 1575-85. ©2016 AACR.

Neutrophils in the tumor microenvironment: trying to heal the wound that cannot heal

Neutrophils are the first responders to infection and injury and are critical for antimicrobial host defense. Through the generation of reactive oxidants, activation of granular constituents and neutrophil extracellular traps, neutrophils target microbes and prevent their dissemination. While these pathways are beneficial in the context of trauma and infection, their off-target effects in the context of tumor are variable. Tumor-derived factors have been shown to reprogram the marrow, skewing toward the expansion of myelopoiesis. This can result in stimulation of both neutrophilic leukocytosis and the release of immature granulocytic populations that accumulate in circulation and in the tumor microenvironment. While activated neutrophils have been shown to kill tumor cells, there is growing evidence for neutrophil activation driving tumor progression and metastasis through a number of pathways, including stimulation of thrombosis and angiogenesis, stromal remodeling, and impairment of T cell-dependent anti-tumor immunity. There is also growing appreciation of neutrophil heterogeneity in cancer, with distinct neutrophil populations promoting cancer control or progression. In addition to the effects of tumor on neutrophil responses, anti-neoplastic treatment, including surgery, chemotherapy, and growth factors, can influence neutrophil responses. Future directions for research are expected to result in more mechanistic knowledge of neutrophil biology in the tumor microenvironment that may be exploited as prognostic biomarkers and therapeutic targets.

Elevated MTSS1 expression associated with metastasis and poor prognosis of residual hepatitis B-related hepatocellular carcinoma

Background

Hepatectomy generally offers the best chance of long-term survival for patients with hepatocellular carcinoma (HCC). Many studies have shown that hepatectomy accelerates tumor metastasis, but the mechanism remains unclear.

Methods

An orthotopic nude mice model with palliative HCC hepatectomy was performed in this study. Metastasis-related genes in tumor following resection were screened; HCC invasion, metastasis, and some molecular alterations were examined in vivo and in vitro. Clinical significance of key gene mRNA expression was also analyzed.

Results

Metastasis suppressor 1 (MTSS1) located in the central position of gene function net of residual HCC. MTSS1 was up-regulated in residual tumor after palliative resection. In hepatitis B-related HCC patients undergone palliative hepatectomy, those with higher MTSS1 mRNA expression accompanied by activation of matrix metalloproteinase 2 (MMP2) in residual HCC, had earlier residual HCC detection after hepatectomy and poorer survival when compared to those with lower MTSS1. In different cell lines, the levels of MTSS1 mRNA increased in parallel with metastatic potential. MTSS1 down regulation via siRNA decreased MMP2 activity, reduced invasive potentials of HCC by 28.9 % in vitro, and averted the deteriorated lung metastatic extent in vivo.

Conclusions

The poor prognosis of hepatitis B-related HCC patients following palliative hepatectomy associates with elevated MTSS1 mRNA expression; therefore, MTSS1 may provide a new research field for HCC diagnosis and treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0361-8) contains supplementary material, which is available to authorized users.

Identification of breast cancer margins using intraoperative near-infrared imaging

BACKGROUND AND OBJECTIVES

Current methods of intraoperative breast cancer margin assessment are labor intensive, not fully reliable, and time consuming; therefore novel strategies are necessary. We hypothesized that near infrared (NIR) intraoperative molecular imaging using systemic indocyanine green (ICG) would be helpful in discerning tumor margins.

METHODS

A mammary cancer cell line, 4T1, was used to establish tumors in mouse flanks (n = 60). Tumors were excised 24 hr after intravenous ICG. Assessment of residual tumor in the wound bed was performed using a combination of NIR imaging and traditional method (by visual inspection and palpation) versus traditional method alone. Next we performed a clinical trial to evaluate the role of NIR imaging after systemic ICG for the margin assessment of 12 patients undergoing breast-conserving surgery.

RESULTS

Traditional margin assessment identified 30% of positive margins while NIR imaging identified 90% of positive margins. In our clinical trial, all tumors were detected by NIR imaging and there was fluorescent evidence of residual tumor in the tumor bed in 6 of the 12 patients. None of these patients had positive margins on pathology.

CONCLUSIONS

Systemic ICG reliably accumulates in breast cancers in murine models as well as human breast cancer. While NIR imaging is helpful for detection of retained tumor margins in our animal model, intraoperative imaging for precise margin detection will need further refinement before clinical value can be obtained. J. Surg. Oncol. 2016;113:508-514. © 2016 Wiley Periodicals, Inc.

Vaccines for established cancer: overcoming the challenges posed by immune evasion

Therapeutic vaccines preferentially stimulate T cells against tumour-specific epitopes that are created by DNA mutations or oncogenic viruses. In the setting of premalignant disease, carcinoma in situ or minimal residual disease, therapeutic vaccination can be clinically successful as monotherapy; however, in established cancers, therapeutic vaccines will require co-treatments to overcome immune evasion and to become fully effective. In this Review, we discuss the progress that has been made in overcoming immune evasion controlled by tumour cell-intrinsic factors and the tumour microenvironment. We summarize how therapeutic benefit can be maximized in patients with established cancers by improving vaccine design and by using vaccines to increase the effects of standard chemotherapies, to establish and/or maintain tumour-specific T cells that are re-energized by checkpoint blockade and other therapies, and to sustain the antitumour response of adoptively transferred T cells.

Tumor infiltrating immune cells in gliomas and meningiomas

Tumor-infiltrating immune cells are part of a complex microenvironment that promotes and/or regulates tumor development and growth. Depending on the type of cells and their functional interactions, immune cells may play a key role in suppressing the tumor or in providing support for tumor growth, with relevant effects on patient behavior. In recent years, important advances have been achieved in the characterization of immune cell infiltrates in central nervous system (CNS) tumors, but their role in tumorigenesis and patient behavior still remain poorly understood. Overall, these studies have shown significant but variable levels of infiltration of CNS tumors by macrophage/microglial cells (TAM) and to a less extent also lymphocytes (particularly T-cells and NK cells, and less frequently also B-cells). Of note, TAM infiltrate gliomas at moderate numbers where they frequently show an immune suppressive phenotype and functional behavior; in contrast, infiltration by TAM may be very pronounced in meningiomas, particularly in cases that carry isolated monosomy 22, where the immune infiltrates also contain greater numbers of cytotoxic T and NK-cells associated with an enhanced anti-tumoral immune response. In line with this, the presence of regulatory T cells, is usually limited to a small fraction of all meningiomas, while frequently found in gliomas. Despite these differences between gliomas and meningiomas, both tumors show heterogeneous levels of infiltration by immune cells with variable functionality. In this review we summarize current knowledge about tumor-infiltrating immune cells in the two most common types of CNS tumors-gliomas and meningiomas-, as well as the role that such immune cells may play in the tumor microenvironment in controlling and/or promoting tumor development, growth and control.

Targeting myeloid cells in the tumor microenvironment enhances vaccine efficacy in murine epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is typically diagnosed at advanced stages, and is associated with a high relapse rate. Patients in remission are ideal candidates for immunotherapy aimed at cure or prolonging disease-free periods. However, immunosuppressive pathways in the tumor microenvironment are obstacles to durable anti-tumor immunity. In a metastatic syngeneic mouse model of EOC, immunosuppressive macrophages and myeloid-derived suppressor cells (MDSCs) accumulate in the local tumor environment. In addition, resident peritoneal macrophages from non-tumor-bearing mice were highly immunosuppressive, abrogating stimulated T cell proliferation in a cell contact-dependent manner. Immunization with microparticles containing TLR9 and NOD-2 ligands (MIS416) significantly prolonged survival in tumor-bearing mice. The strategy of MIS416 immunization followed by anti-CD11b administration further delayed tumor progression, thereby establishing the proof of principle that myeloid depletion can enhance vaccine efficacy. In patients with advanced EOC, ascites analysis showed substantial heterogeneity in the relative proportions of myeloid subsets and their immunosuppressive properties. Together, these findings point to immunosuppressive myeloid cells in the EOC microenvironment as targets to enhance vaccination. Further studies of myeloid cell accumulation and functional phenotypes in the EOC microenvironment may identify patients who are likely to benefit from vaccination combined with approaches that deplete tumor-associated myeloid cells.

Clinical implications of positive margins following non-small cell lung cancer surgery

Positive margins following pulmonary resection of non-small cell lung cancer (NSCLC) occur in approximately 5-15% of patients undergoing a curative procedure. The presence of positive margins negatively impacts long-term outcomes by setting the stage for local and potentially distant disease recurrence. Despite major clinical ramifications, there are very few dedicated reports that examine the implications of positive margins following surgery for NSCLC. Furthermore, published series are typically retrospective studies from single institutions. In this review we analyze published data with special consideration of four pertinent questions: (i) what are the long term outcomes of a positive margin following pulmonary resection?, (ii) is intraoperative margin assessment by frozen section reliable?, (iii) what is the optimal distance of the tumor margin to the surgical margin?, and (iv) should adjuvant chemotherapy and/or radiation therapy be used in the setting of a positive surgical margin?