CD4(+)CD25high regulatory T cells increase with tumor stage in patients with gastric and esophageal cancers

Spatial heterogeneity and prognostic significance of TAMs and TILs infiltrates in different staging esophageal squamous carcinoma

BACKGROUND

The prognostic value and clinical relevance of tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs) in esophageal squamous cell carcinoma (ESCC) remain unclear.

AIMS

To investigate the prognostic value and functional involvement of TILs in ESCC.

METHODS

We included 40 patients across different stages of ESCC from Xinjiang. Multiplex fluorescent immunohistochemistry characterized TILs and TAMs. TILs in different tumor regions were quantified and correlated with overall survival (OS) using log-rank test and Cox regression analyses.

RESULTS

Invasive ESCC exhibited increased CD4 T cells and Tregs compared to carcinoma in situ, with a higher Tregs/CD4 T cells ratio (p < 0.05). TAMs, primarily in stromal regions, were significantly associated with Foxp3+ cells (p < 0.05). Higher infiltration of stromal TAMs and a higher CD4/CD8 T cells ratio correlated with poorer OS, while a higher CD8 T/Foxp3+ cells ratio indicated better survival. Multivariate Cox analysis revealed TNM stage, tumor length, and stromal CD4/CD8 T cells ratio as independent prognostic factors (p < 0.05). An immune prognostic risk score-based nomogram was constructed to predict patient outcomes.

CONCLUSIONS

The spatial distribution and abundance of TILs significantly correlated with prognosis, providing a useful immune classification for ESCC.

Nanoparticle-mediated metronomic chemotherapy in cancer: A paradigm of precision and persistence

Current methods of cancer therapy have demonstrated enormous potential in tumor inhibition. However, a high dosage regimen of chemotherapy results in various complications which affect the normal body cells. Tumor cells also develop resistance against the prescribed drugs in the whole treatment regimen increasing the risk of cancer relapse. Metronomic chemotherapy is a modern treatment method that involves administering drugs at low doses continuously, allowing the drug sufficient time to take its effect. This method ensures that the toxicity of the drugs is to a minimum in comparison to conventional chemotherapy. Nanoparticles have shown efficacy in delivering drugs to the tumor cells in various cancer therapies. Combining nanoparticles with metronomic chemotherapy can yield better treatment results. This combination stimulates the immune system, improving cancer cells recognition by immune cells. Evidence from clinical and pre-clinical trials supports the use of metronomic delivery for drug-loaded nanoparticles. This review focuses on the functionalization of nanoparticles for improved drug delivery and inhibition of tumor growth. It emphasizes the mechanisms of metronomic chemotherapy and its conjunction with nanotechnology. Additionally, it explores tumor progression and the current methods of chemotherapy. The challenges associated with nano-based metronomic chemotherapy are outlined, paving the way for prospects in this dynamic field.

Interaction of microbiota, mucosal malignancies, and immunotherapy-Mechanistic insights

The microbiome has emerged as a crucial modulator of host-immune interactions and clearly impacts tumor development and therapy efficacy. The microbiome is a double-edged sword in cancer development and therapy as both pro-tumorigenic and anti-tumorigenic bacterial taxa have been identified. The staggering number of association-based studies in various tumor types has led to an enormous amount of data that makes it difficult to identify bacteria that promote tumor development or modulate therapy efficacy from bystander bacteria. Here we aim to comprehensively summarize the current knowledge of microbiome-host immunity interactions and cancer therapy in various mucosal tissues to find commonalities and thus identify potential functionally relevant bacterial taxa. Moreover, we also review recent studies identifying specific bacteria and mechanisms through which the microbiome modulates cancer development and therapy efficacy.

Tumor cell stemness in gastrointestinal cancer: regulation and targeted therapy

The cancer stem cells are a rare group of self-renewable cancer cells capable of the initiation, progression, metastasis and recurrence of tumors, and also a key contributor to the therapeutic resistance. Thus, understanding the molecular mechanism of tumor stemness regulation, especially in the gastrointestinal (GI) cancers, is of great importance for targeting CSC and designing novel therapeutic strategies. This review aims to elucidate current advancements in the understanding of CSC regulation, including CSC biomarkers, signaling pathways, and non-coding RNAs. We will also provide a comprehensive view on how the tumor microenvironment (TME) display an overall tumor-promoting effect, including the recruitment and impact of cancer-associated fibroblasts (CAFs), the establishment of an immunosuppressive milieu, and the induction of angiogenesis and hypoxia. Lastly, this review consolidates mainstream novel therapeutic interventions targeting CSC stemness regulation.

Metronomic chemotherapy and drug repurposing: A paradigm shift in oncology

Cancer represents a significant global health and economic burden due to its high mortality rates. While effective in some instances, traditional chemotherapy often falls short of entirely eradicating various types of cancer. It can cause severe side effects due to harm to healthy cells. Two therapeutic approaches have risen to the forefront to address these limitations: metronomic chemotherapy (MCT) and drug repurposing. Metronomic chemotherapy is an innovative approach that breaks from traditional models. It involves the administration of chemotherapeutic regimens at lower doses, without long drug-free intervals that have previously been a hallmark of such treatments. This method offers a significant reduction in side effects and improved disease management. Simultaneously, drug repurposing has gained considerable attraction in cancer treatment. This approach involves utilizing existing drugs, initially developed for other therapeutic purposes, as potential cancer treatments. The application of known drugs in a new context accelerates the timeline from laboratory to patient due to pre-existing safety and dosage data. The intersection of these two strategies gives rise to a novel therapeutic approach named 'Metronomics.' This approach encapsulates the benefits of both MCT and drug repurposing, leading to reduced toxicity, potential for oral administration, improved patient quality of life, accelerated clinical implementation, and enhanced affordability. Numerous clinical studies have endorsed the efficacy of metronomic chemotherapy with tolerable side effects, underlining the potential of Metronomics in better cancer management, particularly in low- and middle-income countries. This review underscores the benefits and applications of metronomic chemotherapy and drug repurposing, specifically in the context of breast cancer, showcasing the promising results of pre-clinical and clinical studies. However, we acknowledge the necessity of additional clinical investigations to definitively establish the role of metronomic chemotherapy in conjunction with other treatments in comprehensive cancer management.

Regulatory T cells in gastric cancer: Key controllers from pathogenesis to therapy

Gastric cancer (GC) is a highly aggressive malignancy that remains a significant contributor to cancer-related mortality worldwide, despite a decline in incidence in recent years. Early-stage GC poses a diagnostic challenge due to its asymptomatic nature, leading to poor prognoses for most patients. Conventional treatment approaches, including chemotherapy and surgery, have shown limited efficacy in improving outcomes for GC patients. The advent of immune checkpoint inhibitors (ICIs) has revolutionized cancer therapy, yielding durable responses across various malignancies. However, the clinical benefits of ICIs in GC have been modest, underscoring the need for a comprehensive understanding of immune cell functions within the GC tumor microenvironment (TME). Regulatory T cells (Tregs), a subset of T lymphocytes, play a pivotal role in GC development and progression and serve as prognostic biomarkers for GC patients. This review aims to elucidate the multifaceted roles of Tregs in the pathogenesis, progression, and prognosis of gastric cancer, and establish their actual and future potential as therapeutic targets. By providing insights into the intricate interplay between Tregs and the TME, this review strives to stimulate further investigation and facilitate the development of targeted Treg-based therapeutic strategies for GC.

Nanoformulations-Based Metronomic Chemotherapy: Mechanism, Challenges, Recent Advances, and Future Perspectives

Cancer-related death is a significant health and economic burden worldwide, and some conventional chemotherapy is associated with limited effectiveness in completely curing various cancers, severe adverse effects, and destruction of healthy cells. To overcome the complications associated with conventional treatment, metronomic chemotherapy (MCT) is extensively suggested. In this review, we aim to highlight the importance of MCT over conventional chemotherapeutic approach with emphasis on nanoformulations-based MCT, their mechanism, challenges, recent advances, and future perspectives. Nanoformulations-based MCT revealed remarkable antitumor activity in both preclinical and clinical settings. For example, the metronomic scheduling of oxaliplatin-loaded nanoemulsion and polyethylene glycol-coated stealth nanoparticles incorporating paclitaxel were proven very effective in tumor-bearing mice and rats, respectively. Additionally, several clinical studies have demonstrated the benefit of MCT with acceptable tolerance. Moreover, metronomic might be a promising treatment strategy for improving cancer care in low- and middle-income nations. However, an appropriate alternative to a metronomic regimen for an individual ailment, suitable combinational delivery and scheduling, and predictive biomarkers are certain parts that remain unanswered. Further clinical-based comparative research studies are mandatory to be performed before entailing this treatment modality in clinical practice as alternative maintenance therapy or in place of transferring to therapeutic management.

Current Understanding of Flavonoids in Cancer Therapy and Prevention

Cancer is a major cause of death worldwide, with multiple pathophysiological manifestations. In particular, genetic abnormalities, inflammation, bad eating habits, radiation exposure, work stress, and toxin consumption have been linked to cancer disease development and progression. Recently, natural bioactive chemicals known as polyphenols found in plants were shown to have anticancer capabilities, destroying altered or malignant cells without harming normal cells. Flavonoids have demonstrated antioxidant, antiviral, anticancer, and anti-inflammatory effects. Flavonoid type, bioavailability, and possible method of action determine these biological actions. These low-cost pharmaceutical components have significant biological activities and are beneficial for several chronic disorders, including cancer. Recent research has focused primarily on isolating, synthesizing, and studying the effects of flavonoids on human health. Here we have attempted to summarize our current knowledge of flavonoids, focusing on their mode of action to better understand their effects on cancer.

Safety and efficacy of autologous cell vaccines in solid tumors: a systematic review and meta-analysis of randomized control trials

We conducted a systematic review and meta-analysis of randomized control trials to formally assess the safety and efficacy of autologous whole cell vaccines as immunotherapies for solid tumors. Our primary safety outcome was number, and grade of adverse events. Our primary efficacy outcome was clinical responses. Secondary outcomes included survival metrics and correlative immune assays. We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for studies published between 1946 and August 2020 using any autologous whole cell product in the treatment of any solid tumor. The Cochrane Randomized Controlled Trial risk of bias tool was used to assess risk of bias. Eighteen manuscripts were identified with a total of 714 patients enrolled in control and 808 in vaccine arms. In 698 patients receiving at least one dose of vaccine, treatment was well tolerated with a total of 5 grade III or higher adverse events. Clinical response was reported in a minority (n = 2, 14%) of studies. Autologous cell vaccines were associated with improved overall (HR 1.28, 95% CI 1.01-1.63) and disease-free survival (HR 1.33, 95% CI 1.05-1.67) over thirteen and ten trials respectively. Where reported, immune assays correlated well with clinical outcomes. Our results suggest that autologous whole cell vaccination is safe and efficacious in increasing survival in patients undergoing treatment for solid tumors.Registration: PROSPERO CRD42019140187.

Presence of regulatory T-cells in endometrial cancer predicts poorer overall survival and promotes progression of tumor cells

PURPOSE

Endometrial cancer (EC) is one of the most common gynaecologic malignancies. Tumor infiltrating regulatory T-cells (Treg) have been reported to have a prognostic impact in many malignancies. Immunotherapeutic strategies are gaining interest for advanced and recurrent EC cases, where treatment options are rare. Our study was aimed at determining the value of Treg in EC progression.

METHODS

EC specimens from 275 patients and 28 controls were screened immunohistochemically for the presence of Treg represented by FoxP3. Correlations with clinicopathological and survival parameters were performed. Functional assays were performed using EC cell lines Ishikawa + and RL95-2 after co-culturing with isolated CD4 + CD25 + CD127dim Treg. To assess the influence of EC on the composition of peripheral blood mononuclear cells (PBMC), flow cytometric analyses were performed.

RESULTS

We found that an increased infiltration of Treg was associated with high grades and a reduced overall survival. Treg were almost absent in endometrium tissues from healthy control patients. Co-culture of tumor cells with CD4 + CD25 + CD127dim Treg led to functional changes: enhanced invasion, migration and viability indicated that increased levels of Treg in the tumor microenvironment may promote tumor growth. Furthermore, we found that the presence of EC cells led to phenotypic changes in PBMC, showing significantly increased levels of CD25 and FoxP3.

CONCLUSION

Our results indicate that the presence of Treg in the EC tumor environment is associated with a poorer outcome. A remarkable impact of Treg on tumor cell behaviour and vice versa of tumor cells on PBMC subpopulations support this notion mechanistically. Our findings provide a basis for focusing on Treg as potential future therapeutic targets in EC.

Therapeutic targeting of regulatory T cells in cancer

The success of immunotherapy in oncology underscores the vital role of the immune system in cancer development. Regulatory T cells (Tregs) maintain a fine balance between autoimmunity and immune suppression. They have multiple roles in the tumor microenvironment (TME) but act particularly in suppressing T cell activation. This review focuses on the detrimental and sometimes beneficial roles of Tregs in tumors, our current understanding of recruitment and stabilization of Tregs within the TME, and current Treg-targeted therapeutics. Research identifying subpopulations of Tregs and their respective functions and interactions within the complex networks of the TME will be crucial to develop the next generation of immunotherapies. Through these advances, Treg-targeted immunotherapy could have important implications for the future of oncology.

Implications of regulatory T cells in anti-cancer immunity: from pathogenesis to therapeutics

Regulatory T cells (Tregs) play an essential role in maintaining immune tolerance and suppressing inflammation. However, Tregs present major hurdle in eliciting potent anti-cancer immune responses. Therefore, curbing the activity of Tregs represents a novel and efficient way towards successful immunotherapy of cancer. Moreover, there is an emerging interest in harnessing Treg-based strategies for augmenting anti-cancer immunity in different types of the disease. This review summarises the crucial mechanisms of Tregs’ mediated suppression of anti-cancer immunity and strategies to suppress or to alter such Tregs to improve the immune response against tumors. Highlighting important clinical studies, the review also describes current Treg-based therapeutic interventions in cancer, and discusses Treg-suppression by molecular targeting, which may emerge as an effective cancer immunotherapy and as an alternative to detrimental chemotherapeutic agents.

•

Tregs are crucial in maintaining immune tolerance and suppressing inflammation.

•

Tregs present a major obstacle to eliciting potent anti-tumor immune responses.

•

The review summarizes current Treg-based therapeutic interventions in cancer.

•

Treg can be an effective cancer immunotherapy target.

Single-Cell Atlas of Lineage States, Tumor Microenvironment, and Subtype-Specific Expression Programs in Gastric Cancer

Gastric cancer heterogeneity represents a barrier to disease management. We generated a comprehensive single-cell atlas of gastric cancer (>200,000 cells) comprising 48 samples from 31 patients across clinical stages and histologic subtypes. We identified 34 distinct cell-lineage states including novel rare cell populations. Many lineage states exhibited distinct cancer-associated expression profiles, individually contributing to a combined tumor-wide molecular collage. We observed increased plasma cell proportions in diffuse-type tumors associated with epithelial-resident KLF2 and stage-wise accrual of cancer-associated fibroblast subpopulations marked by high INHBA and FAP coexpression. Single-cell comparisons between patient-derived organoids (PDO) and primary tumors highlighted inter- and intralineage similarities and differences, demarcating molecular boundaries of PDOs as experimental models. We complemented these findings by spatial transcriptomics, orthogonal validation in independent bulk RNA-sequencing cohorts, and functional demonstration using in vitro and in vivo models. Our results provide a high-resolution molecular resource of intra- and interpatient lineage states across distinct gastric cancer subtypes.

SIGNIFICANCE

We profiled gastric malignancies at single-cell resolution and identified increased plasma cell proportions as a novel feature of diffuse-type tumors. We also uncovered distinct cancer-associated fibroblast subtypes with INHBA-FAP-high cell populations as predictors of poor clinical prognosis. Our findings highlight potential origins of deregulated cell states in the gastric tumor ecosystem. This article is highlighted in the In This Issue feature, p. 587.

Cancer Stem Cells and the Tumor Microenvironment in Gastric Cancer

Gastric cancer (GC) remains one of the leading causes of cancer-related death worldwide. Cancer stem cells (CSCs) might be responsible for tumor initiation, relapse, metastasis and treatment resistance of GC. The tumor microenvironment (TME) comprises tumor cells, immune cells, stromal cells and other extracellular components, which plays a pivotal role in tumor progression and therapy resistance. The properties of CSCs are regulated by cells and extracellular matrix components of the TME in some unique manners. This review will summarize current literature regarding the effects of CSCs and TME on the progression and therapy resistance of GC, while emphasizing the potential for developing successful anti-tumor therapy based on targeting the TME and CSCs.

Cyclooxygenases and Prostaglandins in Tumor Immunology and Microenvironment of Gastrointestinal Cancer

Chronic inflammation is a known risk factor for gastrointestinal cancer. The evidence that nonsteroidal anti-inflammatory drugs suppress the incidence, growth, and metastasis of gastrointestinal cancer supports the concept that a nonsteroidal anti-inflammatory drug target, cyclooxygenase, and its downstream bioactive lipid products may provide one of the links between inflammation and cancer. Preclinical studies have demonstrated that the cyclooxygenase-2-prostaglandin E₂ pathway can promote gastrointestinal cancer development. Although the role of this pathway in cancer has been investigated extensively for 2 decades, only recent studies have described its effects on host defenses against transformed epithelial cells. Overcoming tumor-immune evasion remains one of the major challenges in cancer immunotherapy. This review summarizes the impacts of the cyclooxygenase-2-prostaglandin E₂ pathway on gastrointestinal cancer development. Our focus was to highlight recent advances in our understanding of how this pathway induces tumor immune evasion.

Comparing syngeneic and autochthonous models of breast cancer to identify tumor immune components that correlate with response to immunotherapy in breast cancer

BACKGROUND

The heterogeneity of the breast tumor microenvironment (TME) may contribute to the lack of durable responses to immune checkpoint blockade (ICB); however, mouse models to test this are currently lacking. Proper selection and use of preclinical models are necessary for rigorous, preclinical studies to rapidly move laboratory findings into the clinic.

METHODS

Three versions of a common syngeneic model derived from the MMTV-PyMT autochthonous model were generated by inoculating 1E6, 1E5, or 1E4 cells derived from the MMTV-PyMT mouse into wildtype recipient mice. To elucidate how tumor latency and TME heterogeneity contribute to ICB resistance, comprehensive characterization of the TME using quantitative flow-cytometry and RNA expression analysis (NanoString) was performed. Subsequently, response to ICB was tested. These procedures were repeated using the EMT6 breast cancer model.

RESULTS

The 3 syngeneic versions of the MMTV-PyMT model had vastly different TMEs that correlated to ICB response. The number of cells used to generate syngeneic tumors significantly influenced tumor latency, infiltrating leukocyte populations, and response to ICB. These results were confirmed using the EMT6 breast cancer model. Compared to the MMTV-PyMT autochthonous model, all 3 MMTV-PyMT syngeneic models had significantly more tumor-infiltrating lymphocytes (TILs; CD3⁺, CD4⁺, and CD8⁺) and higher proportions of PD-L1-positive myeloid cells, whereas the MMTV-PyMT autochthonous model had the highest frequency of myeloid cells out of total leukocytes. Increased TILs correlated with response to anti-PD-L1 and anti-CTLA-4 therapy, but PD-L1expression on tumor cells or PD-1 expression of T cells did not.

CONCLUSIONS

These studies reveal that tumor cell number correlates with tumor latency, TME, and response to ICB. ICB-sensitive and resistant syngeneic breast cancer models were identified, in which the 1E4 syngeneic model was most resistant to ICB. Given the lack of benefit from ICB in breast cancer, identifying robust murine models presented here provides the opportunity to further interrogate the TME for breast cancer treatment and provide novel insights into therapeutic combinations to overcome ICB resistance.

Tumor-infiltrating FoxP3+ T cells are associated with poor prognosis in oral squamous cell carcinoma

OBJECTIVES

Squamous cell carcinoma is the most common malignancy in the oral cavity. Moreover, human papillomavirus (HPV) infection has been recently implicated in the onset of oral squamous cell carcinoma (OSCC). Regulatory T cells (Tregs) are Forkhead box P3 (FoxP3) positive and are normally involved in the mechanism by which organisms escape attacks from their own immune system; however, in tumors, these cells are known to suppress antitumor immunity and block the attack against tumors. The present study evaluated the associations of the number of Tregs and HPV infection with prognoses in patients with OSCC.

MATERIAL AND METHODS

Samples from 106 patients diagnosed with OSCC were evaluated by immunohistochemical staining for the identification of FoxP3+ Tregs and HPV. The relationship between the observed number of Foxp3-positive cells, the presence/absence of HPV infection and associations with clinicopathological indicators were analyzed.

RESULTS

Tissues were classified into high (High) and low (Low) Treg count groups, with 69 patients classified as High and 37 classified as Low. The prognoses were significantly better in the Low group compared with the High group (p = 0.04). FoxP3 expression may have had some effect on nodal metastases (p = 0.09). HPV antigens were detected in 65 patients, but there were no significant associations with prognosis (p = 0.34). HPV-infected tumors were more common in the gums and tongues than in the lips, cheeks, and floor of the mouth (p = 0.05).

CONCLUSIONS

These results indicate that Tregs in tumor sites are associated with worsened prognoses of patients with OSCC and suggest potential therapies targeting Tregs in OSCC.

Stem cells-derived natural killer cells for cancer immunotherapy: current protocols, feasibility, and benefits of ex vivo generated natural killer cells in treatment of advanced solid tumors

Nowadays, natural killer (NK) cell-based immunotherapy provides a practical therapeutic strategy for patients with advanced solid tumors (STs). This approach is adaptively conducted by the autologous and identical NK cells after in vitro expansion and overnight activation. However, the NK cell-based cancer immunotherapy has been faced with some fundamental and technical limitations. Moreover, the desirable outcomes of the NK cell therapy may not be achieved due to the complex tumor microenvironment by inhibition of intra-tumoral polarization and cytotoxicity of implanted NK cells. Currently, stem cells (SCs) technology provides a powerful opportunity to generate more effective and universal sources of the NK cells. Till now, several strategies have been developed to differentiate types of the pluripotent and adult SCs into the mature NK cells, with both feeder layer-dependent and/or feeder laye-free strategies. Higher cytokine production and intra-tumoral polarization capabilities as well as stronger anti-tumor properties are the main features of these SCs-derived NK cells. The present review article focuses on the principal barriers through the conventional NK cell immunotherapies for patients with advanced STs. It also provides a comprehensive resource of protocols regarding the generation of SCs-derived NK cells in an ex vivo condition.

Hypoxia and its impact on the tumour microenvironment of gastroesophageal cancers

The malfeasant role of the hypoxic tumour microenvironment (TME) in cancer progression was recognized decades ago but the exact mechanisms that augment the hallmarks of cancer and promote treatment resistance continue to be elucidated. Gastroesophageal cancers (GOCs) represent a major burden of worldwide disease, responsible for the deaths of over 1 million people annually. Disentangling the impact of hypoxia in GOCs enables a better overall understanding of the disease pathogenesis while shining a light on novel therapeutic strategies and facilitating precision treatment approaches with the ultimate goal of improving outcomes for patients with these diseases. This review discusses the underlying principles and processes of the hypoxic response and the effect of hypoxia in promoting the hallmarks of cancer in the context of GOCs. We focus on its bidirectional influence on inflammation and how it drives angiogenesis, innate and adaptive immune evasion, metastasis, and the reprogramming of cellular bioenergetics. The contribution of the hypoxic GOC TME to treatment resistance is examined and a brief overview of the pharmacodynamics of hypoxia-targeted therapeutics is given. The principal methods that are used in measuring hypoxia and how they may enhance prognostication or provide rationale for individually tailored management in the case of tumours with significant hypoxic regions are also discussed.

TLR2 ligation protects effector T cells from regulatory T-cell mediated suppression and repolarizes T helper responses following MVA-based cancer immunotherapy

Cancer immunotherapy is hampered by the immunosuppression maintained by regulatory T cells (Tregs) in tumor-bearing hosts. Stimulation of the Toll-like receptor 2 (TLR2) by Pam3Cys is known to affect Treg-mediated suppression. We found that Pam3Cys increases the proliferation of both CD4⁺ effector T cells (Teffs) and Tregs co-cultured in vitro, but did not induce the proliferation of Tregs alone upon CD3 and CD28 stimulation. In a mouse model of RMA-MUC1 tumors, Pam3Cys was administered either alone or in combination with a modified vaccinia ankara (MVA)-based mucin 1 (MUC1) therapeutic vaccine. The combination of Pam3Cys with MVA-MUC1 (1) diminished splenic Treg/CD4⁺ T-cell ratios to those found in tumor-free mice, (2) stimulated a specific anti-MUC1 interferon γ (IFNγ) response and (3) had a significant therapeutic effect on tumor growth and mouse survival. When CD4⁺ Teffs and Tregs were isolated from Pam3Cys-treated mice, Teffs had become resistant to Treg-mediated suppression while upregulating the expression of BclL-x_L. Tregs from Pam3Cys-treated mice were fully suppressive for Teffs from naïve mice. Bcl-x_L was induced by Pam3Cys with different kinetics in Tregs and Teffs. Teff from Pam3Cys-treated mice produced increased levels of Th1 and Th2-type cytokines and an interleukin (IL)-6-dependent secretion of IL-17 was observed in Teff:Treg co-cultures, suggesting that TLR2 stimulation had skewed the immune response toward a Th17 profile. Our results show for the first time that in a tumor-bearing host, TLR2 stimulation with Pam3Cys affects both Tregs and Teffs, protects Teff from Treg-mediated suppression and has strong therapeutic effects when combined with an MVA-based antitumor vaccine.

Immunophenotype of Gastric Tumors Unveils a Pleiotropic Role of Regulatory T Cells in Tumor Development

Gastric cancer (GC) patients display increased regulatory T cell (Tregs) numbers in peripheral blood and among tumor-infiltrating lymphocytes. Nevertheless, the role of Tregs in GC progression remains controversial. Here, we sought to explore the impact of Tregs in GCs with distinct histology, and whether Tregs can directly influence tumor cell behavior and GC development. We performed a comprehensive immunophenotyping of 82 human GC cases, through an integrated analysis of multispectral immunofluorescence detection of T cells markers and patient clinicopathological data. Moreover, we developed 3D in vitro co-cultures with Tregs and tumor cells that were followed by high-throughput and light-sheet imaging, and their biological features studied with conventional/imaging flow cytometry and Western blotting. We showed that Tregs located at the tumor nest were frequent in intestinal-type GCs but did not associate with increased levels of effector T cells. Our in vitro results suggested that Tregs preferentially infiltrated intestinal-type GC spheroids, induced the expression of IL2Rα and activation of MAPK signaling pathway in tumor cells, and promoted spheroid growth. Accumulation of Tregs in intestinal-type GCs was increased at early stages of the stomach wall invasion and in the absence of vascular and perineural invasion. In this study, we proposed a non-immunosuppressive mechanism through which Tregs might directly modulate GC cells and thereby promote tumor growth. Our findings hold insightful implications for therapeutic strategies targeting intestinal-type GCs and other tumors with similar immune context.

Gastrospheres as a Model of Gastric Cancer Stem Cells Skew Th17/Treg Balance toward Antitumor Th17 Cells

Background

Gastrosphere, an enriched cellular population with stem-like properties believed to be responsible for an escape from immune-mediated destruction. Th17 and Treg cells play a major role in gastric cancer; however, their interaction with gastrospheres remained elusive.

Method

Peripheral blood mononuclear cells were isolated from healthy donors and were cultured with conditioned media of MKN-45 (parental) cells as well as gastrospheres' conditioned media in the context of mixed lymphocyte reaction and in the presence of anti-CD3/CD28 beads. The proliferation was evaluated using CFSE staining; the percentages of CD4⁺CD25⁺FoxP3⁺ Treg and CD4⁺IL-17⁺ Th17 cells and IFN-γ+cells and the production of IL-17, TGF-β, and IL-10 were assessed by flow cytometry and ELISA, respectively. Finally, the cytotoxic potential of induced immune cells was measured by examining the secretion of lactate dehydrogenase from target cells.

Results

The results revealed a decreased expansion of PBMCs postexposure to gastrospheres' conditioned medium which was concomitant with an increased percentage of Th17 and an enhanced Th17 to Treg ratio. The conditioned media of gastrospheres enhanced the secretion of IL-10 and IL-17 and decreased TGF-β. Interestingly, immune cells induced by gastrospheres showed significant cytotoxicity in terms of producing IFN-γ and death induction in target cells. All these changes were related to the upregulation of IL-6, IL-10, and IL-22 in gastrospheres compared to parental cells.

Conclusion

Our study showed that the condition media of gastrospheres can potentially induce Th17 with increasing in their cytotoxic effect. Based on our knowledge, the present study is the first study that emphasizes the role of gastrospheres in the induction of antitumor Th17 cells. However, it should be confirmed with complementary studies in vivo.

Potential mechanisms of tumor progression associated with postoperative infectious complications

There is increasing evidence that postoperative infectious complications (PICs) are associated with poor prognosis after potentially curative surgery. However, the role that PICs play in tumor development remains unclear. In this article, we reviewed the literature for novel insights on the mechanisms of cancer progression associated with PICs. The Medline and EMBASE databases were searched for publications regarding the role of suppression of antitumor immunity by PIC in tumor progression and selected 916 manuscripts were selected for this review. In addition, a summary of the authors' own experimental data from this field was set in the context of current knowledge regarding cancer progression under septic conditions. Initially, sepsis/microbial infection dramatically activates the systemic immune system with increases in pro-inflammatory mediators, which results in the development of systemic inflammatory response syndrome; however, when sepsis persists in septic patients, a shift toward an anti-inflammatory immunosuppressive state, characterized by macrophage deactivation, reduced antigen presentation, T cell anergy, and a shift in the T helper cell pattern to a predominantly TH2-type response, occurs. Thus, various cytokine reactions and the immune status dynamically change during microbial infection, including PIC. We proposed three possible mechanisms for the tumor progression associated with PIC: first, a mechanism in which microbes and/or microbial PAMPs may be directly involved in cancer growth; second, a mechanism in which factors released from immunocompetent cells during infections may affect tumor progression; and third, a mechanism in which factors suppress host tumor immunity during infections, which may result in tumor progression. A more detailed understanding by surgeons of the immunological features in cancer patients with PIC can subsequently open new avenues for improving unfavorable long-term oncological outcomes associated with PICs.

The tumour immune landscape and its implications in cutaneous melanoma

The field of tumour immunology has rapidly advanced in the last decade, leading to the advent of effective immunotherapies for patients with advanced cancers. This highlights the critical role of the immune system in determining tumour development and outcome. The tumour immune microenvironment (TIME) is highly heterogeneous, and the interactions between tumours and the immune system are vastly complex. Studying immune cell function in the TIME will provide an improved understanding of the mechanisms underpinning these interactions. This review examines the role of immune cell populations in the TIME based on their phenotype, function and localisation, as well as contextualising their position in the dynamic relationship between tumours and the immune system. We discuss the function of immune cell populations, examine their impact on patient outcome and highlight gaps in current understanding of their roles in the TIME, both in cancers in general and specifically in melanoma. Studying the TIME by evaluating both pro-tumour and anti-tumour effects may elucidate the conditions which lead to tumour growth and metastasis or immune-mediated tumour regression. Moreover, an in-depth understanding of these conditions could contribute to improved prognostication, more effective use of current immunotherapies and guide the development of novel treatment strategies and therapies.

Better prognosis of gastric cancer patients with high levels of tumor infiltrating lymphocytes is counteracted by PD-1 expression

The prognostic potential of anti-tumor immune responses is becoming increasingly important in adenocarcinoma of the gastroesophageal junction and stomach (AGE/S) especially regarding the use of immune checkpoint inhibitors. This study analyzes for the first time the prognostic impact of tumor-infiltrating lymphocytes (TILs) and checkpoint inhibitors in a large Caucasian cohort in patients with AGE/S. We screened tissue samples from 438 therapy-naïve patients with AGE/S undergoing surgery between 1992 and 2005, examined in a tissue microarray (TMA) and stained against human CD3, CD4, CD8, PD-1, and PD-L1. Out of 438 tissue samples, 210 were eligible for multivariate analysis. This revealed that high infiltration with CD3+, CD4+, or CD8+ TILs was associated with an increased overall survival in AGE/S patients, which could only be confirmed in multivariate analysis for CD3 (HR: 0.326; p = .023). Independent improved survival was limited to gastric cancer patients and to early tumor stages as long as TILs did not express PD-1 (HR: 1.522; p = .021). Subgroup analyses indicate that TIL-dependent anti-tumor immune response is only effective in gastric cancer patients in early stages of disease in PD-1 negative TILs. Combined analysis of PD-1 and CD3 could serve as a prognostic marker for the clinical outcome of gastric cancer patients and could also be of interest for immunotherapy.

Metronomic chemotherapy for patients with metastatic breast cancer: Review of effectiveness and potential use during pandemics

Metronomic chemotherapy (M-CT) is defined as dose dense administration of chemotherapy at lower doses than maximum tolerated dose but at shorter free intervals, to obtain a near continuous exposure of cancer cells to those potentially effective drugs. M-CT is a useful strategy to obtain response, overcome resistance and reduce side effects, with low costs. This review will focus on the use of M-CT in advanced breast cancer (ABC). Cytostatic and cytotoxic effect on cancer cells, the anti-angiogenic and the immunomodulatory effects are its main mechanisms of actions. Many clinical trials proved the efficacy and tolerability of different monotherapies and combinations of chemotherapeutic agents administered in metronomic doses and frequencies in ABC. M-CT is a reasonable option for second and later lines of chemotherapy in metastatic breast cancer including those with prior anthracycline or taxane exposure, older patients and patients with comorbidities, and even as first-line in certain groups of patients. The acceptable efficacy and low toxicity of oral metronomic chemotherapy makes it a reasonable option during COVID-19 pandemic as well as in the post-COVID era which is projected to last for some time.

The Cancer-Immune Set Point in Oesophageal Cancer

Immunotherapy has achieved long-term disease control in a proportion of cancer patients, but determinants of clinical benefit remain unclear. A greater understanding of antitumor immunity on an individual basis is needed to facilitate a precision oncology approach. A conceptual framework called the "cancer-immune set point" has been proposed to describe the equilibrium between factors that promote or suppress anticancer immunity and can serve as a basis to understand the variability in clinical response to immune checkpoint blockade. Oesophageal cancer has a high mutational burden, develops from pre-existing chronic inflammatory lesions and is therefore anticipated to be sensitive to immune checkpoint inhibition. However, both tumour- and patient-specific factors including the immune microenvironment, the microbiome, obesity, and host genetics contribute to an immune set point that confers a lower-than-expected response to checkpoint blockade. Immunotherapy is therefore currently confined to latter lines of treatment of advanced disease, with no reliable predictive biomarker of response. In this review, we examine oesophageal cancer in the context of the cancer-immune set point, discuss factors that contribute to response to immunotherapeutic intervention, and propose areas requiring further investigation to improve treatment response.

Dermatologic toxicities to immune checkpoint inhibitor therapy: A review of histopathologic features

Antineoplastic agents that use the immune system have revolutionized cancer treatment. Specifically, implementation of immune checkpoint inhibitors, monoclonal antibodies that block cytotoxic T-lymphocyte-associated antigen-4, programmed cell death protein 1, or programmed cell death ligand 1 show improved and sustained responses in patients with cancer. However, these agents are associated with a plethora of adverse events, many manifesting in the skin. As the clinical application of cancer immunotherapies expands, understanding the clinical and histopathologic features of associated cutaneous toxicities becomes increasingly important to dermatologists, oncologists, and pathologists to ensure timely diagnosis and appropriate care. This review discusses cutaneous reactions to immune checkpoint inhibitors, focusing on histopathologic features.

Systemic interleukin 10 levels indicate advanced stages while interleukin 17A levels correlate with reduced survival in esophageal adenocarcinomas

Introduction

Reflux promotes esophageal adenocarcinomas (EAC) creating a chronic inflammatory environment. EAC show an increasing incidence in the Western World and median survival rates are still low. The main reasons for poor prognosis despite new multimodal therapies are diagnosis of EACs at an already advanced stage and distant metastases. Hence, we wanted to investigate the presence of systemic inflammatory interleukins (IL) and their impact on patient prognosis.

Material and methods

Systemic expression levels of pro- and anti-inflammatory markers (IL-2, IL-4, IL-6, IL-10, IL-17A and IL-22) in the sera of 43 EAC patients without neoadjuvant radiochemotherapy were measured by flow cytometric analysis. A correlation to clinicopathological data was performed. Log-rank and Cox regression analysis were used to investigate the impact on patient survival. 43 sera of age and gender matched healthy volunteers were used as controls.

Results

Increased systemic IL-6 (p = 0.044) and lower IL-17A (p = 0.002) levels were found in EAC patients as opposed to controls. A correlation of IL-10 levels with an increased T stage was found (p = 0.020). Also, systemic IL-10 levels were highly elevated in patients with distant metastasis (p<0.001). However, only systemic IL-17A levels had an influence on patient survival in multivariate analysis.

Conclusion

Systemic IL-6 levels are increased, while IL-17A levels are reduced in EAC patients compared to healthy controls. In addition, circulating IL-10 might help to identify patients with advanced disease and high IL-17A might indicate a limited prognosis.

Low Dose Cyclophosphamide Modulates Tumor Microenvironment by TGF-β Signaling Pathway

The tumor microenvironment has been recently recognized as a critical contributor to cancer progression and anticancer therapy-resistance. Cyclophosphamide (CTX) is a cytotoxic agent commonly used in clinics for the treatment of cancer. Previous reports demonstrated that CTX given at low continuous doses, known as metronomic schedule, mainly targets endothelial cells and circulating Tregs with unknown mechanisms. Here, we investigated the antitumor activity of two different metronomic schedules of CTX along with their corresponding MTD regimen and further explored their effect on immune function and tumor microenvironment. Toxicity evaluation was monitored by overall survival rate, weight loss, and histopathological analysis. A nude mouse model of Lewis lung cancer was established to assess the anti-metastatic effects of CTX in vivo. CD4⁺, CD8⁺, and CD4⁺CD25⁺FoxP3 T cells were selected by flow cytometry analysis. Low and continuous administration of CTX was able to restore immune function via increase of CD4⁺/CD8⁺ T cells and depletion of T regulatory cells, not only in circulatory and splenic compartments, but also at the tumor site. Low-dose CTX also reduced myofibroblasts, accompanied with an increased level of E-cadherin and low N-cadherin, both in the primary tumor and lung through the TGF-β pathway by the downregulated expression of TGF-β receptor 2. Our data may indicate that several other molecular mechanisms of CTX for tumor may be involved in metronomic chemotherapy, besides targeting angiogenesis and regulatory T cells.

Genetic Subtypes of Systemic Anaplastic Large Cell Lymphoma Show Distinct Differences in PD-L1 Expression and Regulatory and Cytotoxic T Cells in the Tumor Microenvironment

Anaplastic large cell lymphomas (ALCL) encompass several subgroups that differ in their clinical presentation, genetic features, and prognosis. We characterized the genetic subgroups of 74 patients with ALCL and correlated programmed death ligand 1 (PD-L1) protein expression and compared the densities and ratios of FOXP3+ T regulatory cells and CD8+ tumor-infiltrating lymphocytes (TILs) in tumor cells and the immune microenvironment. The subgroups included anaplastic lymphoma kinase (ALK)-positive (ALK+) ALCL and ALK-negative (ALK-) ALCL and DUSP22-rearranged and nonrearranged ALK- ALCL. None of our cases represented the TP63-rearrangement ALK- ALCL subgroup. Our results showed that ALK+ ALCL had a higher expression of PD-L1 in the tumor cells, in contrast to ALK- ALCL, which expressed high PD-L1 in tumor-associated macrophages (TAMs). DUSP22-rearranged ALK- ALCL lacked PD-L1 expression in the tumor cells and instead expressed PD-L1 only in TAMs. There was a significant positive correlation of PD-L1 expression between tumor and TAMs in ALK+ ALCL with a negative correlation in ALK- ALCL. Systemic ALCL subgroups had similar densities of CD8+ tumor-infiltrating lymphocytes and FOXP3 T regulatory cells, but differences were observed in the ratio of CD8/FOXP3. Our results suggest that alterations in tumor microenvironment and immune responses exist among systemic ALCL subgroups and these features may account for different clinical behavior and prognosis.

The Gastrointestinal Tumor Microenvironment: An Updated Biological and Clinical Perspective

Gastrointestinal cancers are still responsible for high numbers of cancer-related deaths despite advances in therapy. Tumor-associated cells play a key role in tumor biology, by supporting or halting tumor development through the production of extracellular matrix, growth factors, cytokines, and extracellular vesicles. Here, we review the roles of these tumor-associated cells in the initiation, angiogenesis, immune modulation, and resistance to therapy of gastrointestinal cancers. We also discuss novel diagnostic and therapeutic strategies directed at tumor-associated cells and their potential benefits for the survival of these patients.

Immunotherapy in HER2-positive breast cancer: state of the art and future perspectives

Breast cancer (BC) is a complex disease with primary or acquired incurability characteristics in a significant part of patients. Immunotherapeutical agents represent an emerging option for breast cancer treatment, including the human epidermal growth factor 2 positive (HER2+) subtype. The immune system holds the ability to spontaneously implement a defensive response against HER2+ BC cells through complex mechanisms which can be exploited to modulate this response for obtaining a clinical benefit. Initial immune system modulating strategies consisted mostly in vaccine therapies, which are still being investigated and improved. However, the entrance of trastuzumab into the scenery of HER2+ BC treatment was the real game changing event, which embodied a dominant immune-mediated mechanism. More recently, the advent of the immune checkpoint inhibitors has caused a new paradigm shift for immuno-oncology, with promising initial results also for HER2+ BC. Breast cancer has been traditionally considered poorly immunogenic, being characterized by relatively low tumor mutation burden (TMB). Nevertheless, recent evidence has revealed high tumor infiltrating lymphocytes (TILs) and programmed cell death-ligand 1 (PD-L1) expression in a considerable proportion of HER2+ BC patients. This may translate into a higher potential to elicit anti-cancer response and, therefore, wider possibilities for the use and implementation of immunotherapy in this subset of BC patients. We are herein presenting and critically discussing the most representative evidence concerning immunotherapy in HER2+ BC cancer, both singularly and in combination with therapeutic agents acting throughout HER2-block, immune checkpoint inhibition and anti-cancer vaccines. The reader will be also provided with hints concerning potential future projection of the most promising immutherapeutic agents and approaches for the disease of interest.

Tumor-Infiltrating Immunosuppressive Cells in Cancer-Cell Plasticity, Tumor Progression and Therapy Response

In most tumors, cancer cells show the ability to dynamically transit from a non-cancer stem-like cell to a cancer stem-like cell (CSC) state and vice versa. This cell plasticity has been associated with the epithelial-to-mesenchymal transition program (EMT) and can be regulated by tumor cell-intrinsic mechanisms and complex interactions with various tumor microenvironment (TME) components. These interactions favor the generation of a specific "CSC niche" that helps maintain the main properties, phenotypic plasticity and metastatic potential of this subset of tumor cells. For this reason, TME has been recognized as an important promoter of tumor progression and therapy resistance. Tumors have evolved a network of immunosuppressive mechanisms that limits the cytotoxic T cell response to cancer cells. Some key players in this network are tumor-associated macrophages, myeloid-derived suppressor cells and regulatory T cells, which not only favor a pro-tumoral and immunosuppressive environment that supports tumor growth and immune evasion, but also negatively influences immunotherapy. Here, we review the relevance of cytokines and growth factors provided by immunosuppressive immune cells in regulating cancer-cell plasticity. We also discuss how cancer cells remodel their own niche to promote proliferation, stemness and EMT, and escape immune surveillance. A better understanding of CSC-TME crosstalk signaling will enable the development of effective targeted or immune therapies that block tumor growth and metastasis.

Stereotactic Ablative Radiation Therapy for Pulmonary Recurrence-Based Oligometastatic Non-Small Cell Lung Cancer: Survival and Prognostic Value of Regulatory T Cells

PURPOSE

We evaluated survival of patients with pulmonary recurrence-based oligometastatic non-small cell lung cancer (NSCLC) whose lesions were all treated with stereotactic ablative radiation therapy (SABR) and the prognostic value of peripheral immune cells.

METHODS AND MATERIALS

In this prospective observational cohort study, we prospectively enrolled 63 patients with oligometastatic NSCLC, for whom all metastases were treated with SABR. Peripheral blood samples were collected 3 days before treatment began, and flow cytometry was used to identify proportions of regulatory T cells (Tregs; CD4+CD25+CD127^low), B cells, NK cells, γδT cells, CD8+CD28+ T cells, and CD8+CD28- T cells. Overall survival (OS) and progression-free survival (PFS) was estimated by the Kaplan-Meier method, and the potential prognostic value of clinicopathologic factors was evaluated by Cox proportional hazards regression.

RESULTS

At a median follow-up time of 19.1 months, estimated OS rates were 84.3% at 1 year, 63.4% at 2 years, and 44.0% at 3 years; corresponding PFS rates were 55.2%, 30.9%, and 25.7%. Estimated local control rates were 96.7% at 1 year and 92.7% at both 2 years and 3 years. Patients with high numbers of Tregs had poorer OS and PFS than did those with low numbers of Tregs (OS: 16.1 months vs not reached, P = .006; PFS: 11.0 vs 21.7 months, P = .013). Treg level was found to be an independent predictor of both OS and PFS in multivariate analyses (OS: hazard ratio 2.68, P = .038; PFS: hazard ratio 2.35, P = .011).

CONCLUSIONS

Our results revealed the independent prognostic value of Tregs in patients treated with SABR for pulmonary recurrence-based oligometastatic NSCLC. Additional treatments may be needed for patients with oligometastatic NSCLC and poor outcomes.

Dietary Flavonoids for Immunoregulation and Cancer: Food Design for Targeting Disease

Flavonoids, one of the most abundant phytochemicals in a diet rich in fruits and vegetables, have been recognized as possessing anti-proliferative, antioxidant, anti-inflammatory, and estrogenic activities. Numerous cellular and animal-based studies show that flavonoids can function as antioxidants by preventing DNA damage and scavenging reactive oxygen radicals, inhibiting formation of DNA adducts, enhancing DNA repair, interfering with chemical damage by induction of Phase II enzymes, and modifying signaling pathways. Recent evidence also shows their ability to regulate the immune system. However, findings from clinical trials have been mixed with no clear consensus on dose, frequency, or type of flavonoids best suited to elicit many of the beneficial effects. Delivery of these bioactive compounds to their biological targets through "targeted designed" food processing strategies is critical to reach effective concentration in vivo. Thus, the identification of novel approaches that optimize flavonoid bioavailability is essential for their successful clinical application. In this review, we discuss the relevance of increasing flavonoid bioavailability, by agricultural engineering and "targeted food design" in the context of the immune system and cancer.

Recent advances in the study of regulatory T cells in gastric cancer

Gastric cancer (GC), which features a complex pathogenesis and mechanism, remains refractory. FOXP3⁺ regulatory T cells (Tregs), which have been implicated in the progression of gastric cancer, play an immunosuppressive role in the tumor microenvironment. However, the prognostic value of Treg infiltration is still controversial in GC patients. Recently, the association of Tregs with the clinicopathological characteristics of GC patients, the prognostic value of Tregs alone or its combination with other factors to GC patients, the role of Tregs in GC tumor microenvironment, clinical applications and Tregs-targeted therapies for GC patients have become hot issues. In this review, we are going to discuss these scientific researches which focused on these topics.

Dysregulation of helper T lymphocytes in esophageal squamous cell carcinoma (ESCC) patients is highly associated with aberrant production of miR-21

Dysregulation of helper T (Th) cell subsets has been contributed to the initiation and propagation of esophageal squamous cell carcinoma (ESCC). Different microRNAs (miRNAs) have been reported to control the development and functions of tumor-associated immune cells in ESCC. Here, we aimed to assess the IL-10, TGF-β, IFN-γ, and IL-17a-producing CD3+CD8- T cells in association whit miR-21, miR-29b, miR-106a, and miR-155 expression in ESCC patients. A total of 34 ESCC patients including 12 newly diagnosed (ND) and 22 under-treatment (UT) cases and also 34 age-matched healthy donors were enrolled. Flow cytometric characterization of stimulated T cells was performed by staining of the cells with fluorescent conjugated specific anti-human CD3 and CD8 cell surface markers as well as IL-17a, IFN-γ, IL-10, and TGF-β intracytoplasmic cytokines. Circulating RNA was extracted from the plasma, and qRT-PCR was used to evaluate the expression of microRNAs. TGF-β plasma levels were also assessed by ELISA. Results showed that the frequency of Th cells was significantly reduced in patients. A significant increase in Treg as well as Th17 cells population in both patient subgroups was observed. ND patients showed elevated level of Th1 cells and IL-10. However the mean expression of IFN-γ was significantly decreased in Th cells. We also detected higher level of miR-21 in the ESCC patients which was significantly correlated with different subsets of Th cells. Our findings revealed that immune response related to the Th cells is highly impaired in ESCC patients. Association between miR-21 and Th subsets could be correlated with the impairment of anti-tumor immunity and ESCC pathogenesis, which could be potentially used as an important target for immunotherapeutic approaches.

The Tolerogenic Function of Regulatory T Cells in Pregnancy and Cancer

Regulatory T cells, a subpopulation of suppressive T cells, are potent mediators of self-tolerance and essential for the suppression of triggered immune responses. The immune modulating capacity of these cells play a major role in both transplantation, autoimmune disease, allergy, cancer and pregnancy. During pregnancy, low numbers of regulatory T cells are associated with pregnancy failure and pregnancy complications such as pre-eclampsia. On the other hand, in cancer, low numbers of immunosuppressive T cells are correlated with better prognosis. Hence, maternal immune tolerance toward the fetus during pregnancy and the escape from host immunosurveillance by cancer seem to be based on similar immunological mechanisms being highly dependent on the balance between immune activation and suppression. As regulatory T cells hold a crucial role in several biological processes, they may also be promising subjects for therapeutic use. Especially in the field of cancer, cell therapy and checkpoint inhibitors have demonstrated that immune-based therapies have a very promising potential in treatment of human malignancies. However, these therapies are often accompanied by adverse autoimmune side effects. Therefore, expanding the knowledge to recognize the complexities of immune regulation pathways shared across different immunological scenarios is extremely important in order to improve and develop new strategies for immune-based therapy. The intent of this review is to highlight the functional characteristics of regulatory T cells in the context of mechanisms of immune regulation in pregnancy and cancer, and how manipulation of these mechanisms potentially may improve therapeutic options.

The Interplay between Immunity and Microbiota at Intestinal Immunological Niche: The Case of Cancer

The gut microbiota is central to the pathogenesis of several inflammatory and autoimmune diseases. While multiple mechanisms are involved, the immune system clearly plays a special role. Indeed, the breakdown of the physiological balance in gut microbial composition leads to dysbiosis, which is then able to enhance inflammation and to influence gene expression. At the same time, there is an intense cross-talk between the microbiota and the immunological niche in the intestinal mucosa. These interactions may pave the way to the development, growth and spreading of cancer, especially in the gastro-intestinal system. Here, we review the changes in microbiota composition, how they relate to the immunological imbalance, influencing the onset of different types of cancer and the impact of these mechanisms on the efficacy of traditional and upcoming cancer treatments.

Glioblastoma Chemoresistance: The Double Play by Microenvironment and Blood-Brain Barrier

For glioblastoma, the tumor microenvironment (TME) is pivotal to support tumor progression and therapeutic resistance. TME consists of several types of stromal, endothelial and immune cells, which are recruited by cancer stem cells (CSCs) to influence CSC phenotype and behavior. TME also promotes the establishment of specific conditions such as hypoxia and acidosis, which play a critical role in glioblastoma chemoresistance, interfering with angiogenesis, apoptosis, DNA repair, oxidative stress, immune escape, expression and activity of multi-drug resistance (MDR)-related genes. Finally, the blood brain barrier (BBB), which insulates the brain microenvironment from the blood, is strongly linked to the drug-resistant phenotype of glioblastoma, being a major physical and physiological hurdle for the delivery of chemotherapy agents into the brain. Here, we review the features of the glioblastoma microenvironment, focusing on their involvement in the phenomenon of chemoresistance; we also summarize recent advances in generating systems to modulate or bypass the BBB for drug delivery into the brain. Genetic aspects associated with glioblastoma chemoresistance and current immune-based strategies, such as checkpoint inhibitor therapy, are described too.

MicroRNAs as Immunotherapy Targets for Treating Gastroenterological Cancers

Gastroenterological cancers are the most common cancers categorized by systems and are estimated to comprise 18.4% of all cancers in the United States in 2017. Gastroenterological cancers are estimated to contribute 26.2% of cancer-related death in 2017. Gastroenterological cancers are characterized by late diagnosis, metastasis, high recurrence, and being refractory to current therapies. Since the current targeted therapies provide limited benefit to the overall response and survival, there is an urgent need for developing novel therapeutic strategy to improve the outcome of gastroenterological cancers. Immunotherapy has been developed and underwent clinical trials, but displayed limited therapeutic benefit. Since aberrant expressions of miRNAs are found in gastroenterological cancers and miRNAs have been shown to regulate antitumor immunity, the combination therapy combining the traditional antibody-based immunotherapy and novel miRNA-based immunotherapy is promising for achieving clinical success. This review summarizes the current knowledge about the miRNAs and long noncoding RNAs that exhibit immunoregulatory roles in gastroenterological cancers and precancerous diseases of digestive system, as well as the miRNA-based clinical trials for gastroenterological cancers. This review also analyzes the ongoing challenge of identifying appropriate therapy candidates for complex and dynamic tumor microenvironment, ensuring efficient and targeted delivery to specific cancer tissues, and developing strategy for avoiding off-target effect.

The anti-PD-1 era - an opportunity to enhance radiotherapy for patients with bladder cancer

An urgent need exists to improve the outcomes of patients with muscle-invasive bladder cancer (MIBC), and especially of those with metastatic disease. Treatments that enhance antitumour immune responses - such as immune-checkpoint inhibition - provide an opportunity to do this. Despite initial success, durable response rates in patients with advanced-stage MIBC treated with novel inhibitory antibodies targeting programmed cell death protein 1 (PD-1) or its endogenous ligand programmed cell death 1 ligand 1 (PD-L1) remain low. Radiotherapy is part of the management of bladder cancer in many patients. Evidence that radiotherapy has immunogenic properties is now available, but radiotherapy-induced immune responses are often negated by immunosuppression within the tumour microenvironment. Anti-PD-1 or anti-PD-L1 antibodies might enhance radiotherapy-induced antitumour immunity. This effect has been demonstrated in preclinical models of bladder cancer, and clinical trials involving this approach are currently recruiting. Combination treatment strategies provide an exciting opportunity for urological oncologists to not only improve the chances of cure in patients undergoing radical treatment for MIBC, but also to increase long-term response rates in those with metastatic disease.

Predictive value of peripheral regulatory T cells in non-small cell lung cancer patients undergoing radiotherapy

Background

Studies increasingly focus on the impact of radiotherapy on immunity; however, the role of peripheral cellular immunity prior to radiotherapy in cancer patients remains largely unknown. In this study, we investigated the predictive roles of lymphocyte subsets on tumor progression in non-small cell lung cancer (NSCLC) patients undergoing radiotherapy, and their expression in NSCLC patients at first relapse.

Methods

We enrolled 70 NSCLC patients and 14 age- and sex-matched healthy donors and tested the lymphocyte subsets in their peripheral blood by flow cytometry. Among them, 40 newly diagnosed patients received radiotherapy and were enrolled to investigate the predictive value of lymphocyte subsets on tumor progression after radiotherapy by uni- and multivariate analyses; 30 patients at first relapse were included to evaluate the differences of lymphocyte subsets between them and first diagnosed patients and healthy volunteers.

Results

Increased proportions of regulatory T cells, CD8+ T cells, and CD8+CD28- T cells and decreased CD4+ T cells and CD4/CD8 ratios were observed in NSCLC patients at first relapse compared to newly diagnosed patients. In the 40 first diagnosed patients undergoing radiotherapy, uni- and multivariate analyses showed that increased level of regulatory T cells correlated with poor progression-free survival (hazard ratio = 2.55 and 3.76, P = 0.022 and 0.010, respectively).

Conclusions

Peripheral regulatory T cells were increased and independently predict tumor progression in NSCLC patients undergoing radiotherapy, suggesting the promising combination of radiotherapy and immunotherapy.

Effects of modified FOLFOX-6 chemotherapy on cellular immune function in patients with gastric cancer

Tumor immunosuppression serves an important role in the occurrence and development of gastric cancer. However, the effect of chemotherapy on the immune function of patients remains unclear. The present study aimed to investigate changes in cellular immune function and regulatory T cells (T_regs) in patients with gastric cancer prior to and following chemotherapy. In the peripheral blood of patients with gastric cancer, the percentage of CD4⁺ T cells was substantially decreased compared with that of healthy controls (11.39±5.91 vs. 22.34±3.37%, respectively; P<0.05). High frequencies of CD8⁺ T cells and T_regs were also observed in the peripheral blood of patients. Although the number of T cells decreased following chemotherapy (the proportions of CD4⁺ and CD8⁺ cells were 8.99±7.31 and 16.00±4.51%, respectively), the ratio of CD4⁺/CD8⁺ T cells increased (0.31±0.17 vs. 0.56±0.22; P<0.05). Furthermore, the level of C-C motif chemokine ligand 20 (CCL20) was increased in patients prior to chemotherapy compared with healthy controls. As the sole receptor for CCL20, a high level of expression of C-C motif chemokine receptor 6 on circulating T_regs was also identified in the patients, which decreased following chemotherapy. These results suggest that chemotherapy may efficiently promote cellular immune function and inhibit immunosuppression in patients with gastric cancer.

Tumor-infiltrating lymphocytes predict prognosis of breast cancer patients treated with anti-Her-2 therapy

PURPOSE

Infiltration of tumor associated lymphocytes and count of its different phenotypes are potentially new independent predictor of prognosis in breast cancer. However, research related to it is less reported in breast cancer patients treated with anti-Her-2 therapy. Thus, we evaluated the relationship between survival and tumor infiltrating lymphocytes including its different phenotypes in tumors of such patients.

METHODS

Between 1999 and 2010, 98 patients diagnosed with primary breast cancer and treated with anti-Her-2 therapy at Sun-Yat-Sen University Cancer Center were included in the study. Biopsy specimens were collected post-operation but before chemotherapy. Tumor infiltrating lymphocytes as well as its FOXP3+, CD68+, IL-17+ phenotypes in both intratumoral and stromal sites and expression of FOXP3 in cancer cells were assessed.

RESULTS

Median follow-up time of 98 patients was 83.3 months (range 7.4-201 months). It suggested that patients with high stromal infiltration of TILs, lower count of FOXP3+ Tregs and CD68+ Mφ in stromal site, and high expression of FOXP3 in cancer cells had longer survival of OS. In multivariate Cox regression analysis, high count of intratumoral CD68+ Mφ [HR: 2.70 (1.00-7.31); p=0.050] and high expression of FOXP3 in cancer cells [HR: 0.29 (0.09-0.91); p=0.034] were independent prognostic factors for overall survival.

CONCLUSIONS

Tumor infiltrating lymphocytes as well as its FOXP3+, CD68+ phenotypes in stromal site, and expression of FOXP3 in cancer cells were significantly associated with OS, suggesting that they can be used as important pathological factor predicting prognosis of breast cancer patients treated with anti-Her-2 therapy.

Current status of immunotherapy and immune biomarkers in gastro-esophageal cancers

Gastroesophageal (GE) cancers continue to be a significant cause of mortality globally. Despite therapeutic advances in oncology, the prognosis of advanced GE cancer remains exceedingly poor. Immunotherapy has caused a major paradigm shift in the field of oncology. Not all patients benefit from these agents and several studies are trying to identify predictive and prognostic biomarkers to better inform and guide treatment decisions. The potential role of immunotherapy in GE cancers is emerging. These cancer types are molecularly and immunologically heterogeneous, and this heterogeneity influences the tumor microenvironment posing a significant challenge to studying biomarkers of response to immunotherapy. Here in this article, we discuss the need for new therapeutic approaches in GE cancers, review the emerging data on the activity of checkpoint inhibitors and the role of biomarkers in this setting.

Metronomic chemotherapy for non-metastatic triple negative breast cancer: Selection is the key

Triple negative breast cancer (TNBC) accounts for 15%-20% of all breast cancer, and is still defined as what it is not. Currently, TNBC is the only type of breast cancer for which there are no approved targeted therapies and maximum tolerated dose chemotherapy with taxanes and anthracycline-containing regimens is still the standard of care in both the neoadjuvant and adjuvant settings. In the last years, metronomic chemotherapy (MC) is being explored as an alternative to improve outcomes in TNBC. In the neoadjuvant setting, purely metronomic and hybrid approaches have been developed with the objective of increasing complete pathologic response (pCR) and prolonging disease free survival. These regimens proved to be very effective achieving pCR rates between 47%-60%, but at the cost of great toxicity. In the adjuvant setting, MC is used to intensify adjuvant chemotherapy and, more promisingly, as maintenance therapy for high-risk patients, especially those with no pCR after neoadjuvant chemotherapy. Considering the dismal prognosis of TNBC, any strategy that potentially improves outcomes, specially being the oral agents broadly available and inexpensive, should be considered and certainly warrants further exploration. Finally, the benefit of MC needs to be validated in properly designed clinical trials were the selection of the population is the key.