Premetastatic niches, exosomes and circulating tumor cells: Early mechanisms of tumor dissemination and the relation to surgery

A gelable polymer loaded with curcumin and apatinib absorbed in gelatin sponge delays postoperative residual tumor growth

Surgical resection of the tumor remains the preferred treatment for most solid tumors at an early stage, however, residual tumor cells after surgical resection poses a considerable obstacle in cancer treatment. Here, we developed a gel carrier using a cellulose-based gel-forming polymer (CT) combined with gelatin sponge (GS) to fill the resection cavity and delay postoperative residual tumor growth. The fabricated gel exhibited a porous nature along with gradual swelling and erosion over time. Curcumin (Cur) and apatinib (Apa) were loaded into CT gel (CT-CA), and a sustained release behavior was observed at pH 7.4 and 6.4 at 37 °C. The preclinical studies indicated that the mouse weight and tissue exhibited no apparent change after administration of the GS-CT compared with the control. The in vivo fluorescence images showed that GS-CT has the capability to regulate the release of Cur and Apa, facilitating the accumulation of these two agents at the surgical tumor site. Moreover, GS-CT loaded Cur and Apa (GS-CT-CA) delayed postoperative residual tumor growth in intraperitoneal and subcutaneous postoperative mouse models. These findings demonstrated that our gel carrier system significantly prevents postoperative residual tumor growth because of enhanced drug accumulation and sustained drug release at the tumor site.

Surgery-related change in cancer cell adhesion associates with recurrence in patients undergoing colorectal cancer surgery

OBJECTIVES

This study aimed to investigate the effect of pre- and postoperative serum on the adhesion of cultured colon cancer cells and their relationship with colorectal cancer recurrence.

BACKGROUND

Colorectal cancer is common, and surgery is the primary treatment choice. However, surgical procedures may be associated with an increased risk of recurrence.

METHOD

434 patients undergoing curatively intended colorectal cancer surgery at Copenhagen University Hospital, Herlev, Denmark, between July 15, 2014, and March 31, 2019, were included in the study. Pre- and postoperative serum samples were collected, and the effect on cellular adhesion was analyzed using a novel high-throughput approach based on CRISPR/Cas9 modified Caco-2 cells and secreted luciferase, named the AdhesionScore assay. The relative risk of postoperative recurrence was estimated using Cox proportional regression analysis.

RESULTS

The difference in adhesion between modified Caco-2 cells seeded in the pre- and postoperative serum showed a significant increase in postoperative adhesion in patients with a recurrence event (p=0.0293). Modeling the adhesion data using multiple logistic regression and Cox proportional regression analyses showed a statistically significant association between increased postoperative adhesion and recurrence (p=0.0155 and p=0.0126, respectively). Patients with the highest AdhesionScore showed the greatest risk of recurrence (HR=7, 95% CI 1.6-37.8, p=0.0130).

CONCLUSIONS

The study found that a difference in the adhesion of Caco-2 cells seeded in pre- and postoperative serum was associated with cancer recurrence following intended curative surgery. This suggests that increased postoperative adhesion may serve as a novel biological marker of recurrence in patients undergoing surgery for colorectal cancer.

Anesthetic Techniques and Cancer Outcomes: What Is the Current Evidence?

It is almost 2 decades since it was first hypothesized that anesthesia technique might modulate cancer biology and thus potentially influence patients' long-term outcomes after cancer surgery. Since then, research efforts have been directed towards elucidating the potential pharmacological and physiological basis for the effects of anesthetic and perioperative interventions on cancer cell biology. In this review, we summarize current laboratory and clinical data. Taken together, preclinical studies suggest some biologic plausibility that cancer cell function could be influenced. However, available clinical evidence suggests a neutral effect. Observational studies examining cancer outcomes after surgery of curative intent for many cancer types under a variety of anesthetic techniques have reported conflicting results, but warranting prospective randomized clinical trials (RCTs). Given the large patient numbers and long follow-up times required for adequate power, relatively few such RCTs have been completed to date. With the sole exception of peritumoral lidocaine infiltration in breast cancer surgery, these RCTs have indicated a neutral effect of anesthetic technique on long-term oncologic outcomes. Therefore, unless there are significant new findings from a few ongoing trials, future investigation of how perioperative agents interact with tumor genes that influence metastatic potential may be justified. In addition, building multidisciplinary collaboration to optimize perioperative care of cancer patients will be important.

Targeting tumor angiogenesis and metabolism with photodynamic nanomedicine

Photodynamic therapy (PDT) holds considerable promise as a tumor treatment modality, characterized by its targeted action, compatibility with other therapeutic approaches, and non - invasive features. PDT can achieve remarkable spatiotemporal precision in tumor ablation through the generation of reactive oxygen species (ROS). Nevertheless, despite its potential in tumor treatment, PDT encounters multiple challenges in practical applications. PDT is highly oxygen - dependent, and thus the effectiveness of PDT can be markedly influenced by tumor hypoxia. The co-existence of abnormal vasculature and metabolic deregulation gives rise to a hypoxic microenvironment, which not only sustains tumor survival but also undermines the therapeutic efficacy of PDT. Consequently, targeting tumor angiogenesis and metabolism is essential for revitalizing PDT. This review emphasizes the mechanisms and strategies for revitalizing PDT in tumor treatment, predominantly concentrating on interfering with tumor angiogenesis and reprogramming tumor cell metabolism. Lastly, the outlining future perspectives and current limitations of PDT are also summarized. This could provide new insights and methodologies for overcoming the challenges associated with PDT in tumor treatment, ultimately advancing the field of PDT.

Sesquiterpene Lactones as Promising Phytochemicals to Cease Metastatic Propagation of Cancer

Cancer metastasis remains the most challenging issue in cancer therapy. Recent reports show that cancer metastasis accounts for over 90% of cancer-associated deaths in the world. Metastasis is a multi-step process by which cancer cells spread to distant tissues and organs beyond the primary site. The metastatic propagation of different cancers is under the surveillance of several regulating processes and factors related to cellular signaling pathways. Plant-derived phytochemicals are bioactive components of plants with a variety of biological and medicinal activities. Several phytochemicals have been shown to target various molecular factors in cancer cells to tackle metastasis. Sesquiterpene lactones, as a diverse group of plant-derived phytochemicals with a variety of biological activities, have been shown to suppress the promotion and progression of different cancer types by acting on multiple cell-signaling pathways. This review article briefly describes the process of metastasis and its components. Then, sesquiterpene lactones with the ability to target and inhibit invasion, migration, and metastasis along with the molecular mechanisms of their effects on different cancers are described in detail.

Lung bronchiectasisas a paradigm of the interplay between infection and colonization on plastic modulation of the pre-metastatic niche

The lungs are most often a preferential target organ for malignant spreading and growth. It is well known that chronic parenchymal inflammation and prolonged injuries represents an independent risk factor for cancer onset. Growing evidence supports the implication of lung microbiota in the pathogenesis of lung cancer. However, the full interplay between chronic inflammation, bacterial colonization, pathologic condition as bronchiectasis and malignant growth deserves better clarification. We here aim at presenting and analyzing original data and discussing the state-of-the-art on the knowledge regarding how this complex milieu acts on the plasticity of the lung pre-metastatic niche to point out the rationale for early diagnosis and therapeutic targeting.

Perioperative Immunosuppressive Factors during Cancer Surgery: An Updated Review

Surgical excision of the primary tumor represents the most frequent and curative procedure for solid malignancies. Compelling evidence suggests that, despite its beneficial effects, surgery may impair immunosurveillance by triggering an immunosuppressive inflammatory stress response and favor recurrence by stimulating minimal residual disease. In addition, many factors interfere with the immune effectors before and after cancer procedures, such as malnutrition, anemia, or subsequent transfusion. Thus, the perioperative period plays a key role in determining oncological outcomes and represents a short phase to circumvent anesthetic and surgical deleterious factors by supporting the immune system through the use of synergistic pharmacological and non-pharmacological approaches. In line with this, accumulating studies indicate that anesthetic agents could drive both protumor or antitumor signaling pathways during or after cancer surgery. While preclinical investigations focusing on anesthetics' impact on the behavior of cancer cells are quite convincing, limited clinical trials studying the consequences on survival and recurrences remain inconclusive. Herein, we highlight the main factors occurring during the perioperative period of cancer surgery and their potential impact on immunomodulation and cancer progression. We also discuss patient management prior to and during surgery, taking into consideration the latest advances in the literature.

Local anaesthetics and chemotherapeutic agents: a systematic review of preclinical evidence of interactions and cancer biology

Background

Local anaesthetics are widely used for their analgesic and anaesthetic properties in the perioperative setting, including surgical procedures to excise malignant tumours. Simultaneously, chemotherapeutic agents remain a cornerstone of cancer treatment, targeting rapidly dividing cancer cells to inhibit tumour growth. The potential interactions between these two drug classes have drawn increasing attention and there are oncological surgical contexts where their combined use could be considered. This review examines existing evidence regarding the interactions between local anaesthetics and chemotherapeutic agents, including biological mechanisms and clinical implications.

Methods

A systematic search of electronic databases was performed as per Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Selection criteria were designed to capture in vitro, in vivo, and clinical studies assessing interactions between local anaesthetics and a wide variety of chemotherapeutic agents. Screening and data extraction were performed independently by two reviewers. The data were synthesised using a narrative approach because of the anticipated heterogeneity of included studies.

Results

Initial searches yielded 1225 relevant articles for screening, of which 43 met the inclusion criteria. The interactions between local anaesthetics and chemotherapeutic agents were diverse and multifaceted. In vitro studies frequently demonstrated altered cytotoxicity profiles when these agents were combined, with variations depending on the specific drug combination and cancer cell type. Mechanistically, some interactions were attributed to modifications in efflux pump activity, tumour suppressor gene expression, or alterations in cellular signalling pathways associated with tumour promotion. A large majority of in vitro studies report potentially beneficial effects of local anaesthetics in terms of enhancing the antineoplastic activity of chemotherapeutic agents. In animal models, the combined administration of local anaesthetics and chemotherapeutic agents showed largely beneficial effects on tumour growth, metastasis, and overall survival. Notably, no clinical study examining the possible interactions of local anaesthetics and chemotherapy on cancer outcomes has been reported.

Conclusions

Reported preclinical interactions between local anaesthetics and chemotherapeutic agents are complex and encompass a spectrum of effects which are largely, although not uniformly, additive or synergistic. The clinical implications of these interactions remain unclear because of the lack of prospective trials. Nonetheless, the modulation of chemotherapy effects by local anaesthetics warrants further clinical investigation in the context of cancer surgery where they could be used together.

Clinical trial registration

Open Science Framework (OSF, project link: https://osf.io/r2u4z).

Exosome-mediated tumor metastasis: Biology, molecular targets and immuno-therapeutic options

Small extracellular vesicles called exosomes play a crucial part in promoting intercellular communication. They act as intermediaries for the exchange of bioactive chemicals between cells, released into the extracellular milieu by a variety of cell types. Within the context of cancer progression, metastasis is a complex process that plays a significant role in the spread of malignant cells from their main site of origin to distant anatomical locations. This complex process plays a key role in the domain of cancer-related deaths. In summary, the trajectory of current research in the field of exosome-mediated metastasis is characterized by its unrelenting quest for more profound understanding of the molecular nuances, the development of innovative diagnostic tools and therapeutic approaches, and the unwavering dedication to transforming these discoveries into revolutionary clinical applications. This unrelenting pursuit represents a shared desire to improve the prognosis for individuals suffering from metastatic cancer and to nudge the treatment paradigm in the direction of more effective and customized interventions.

Neoadjuvant calcium electroporation for potentially curable colorectal cancer

BACKGROUND

The development of new perioperative treatment modalities to activate the immune system in colorectal cancer might have a beneficial effect on reducing the risk of recurrence after surgery. Calcium electroporation is a promising treatment modality that potentially modulates the tumor microenvironment. The aim of this study was to evaluate the safety of the procedure in the neoadjuvant setting in localized left-sided colorectal cancer (CRC).

METHODS

The study included patients with potentially curable sigmoid or rectal cancer with no indication for other neoadjuvant treatment. Patients were offered calcium electroporation as a neoadjuvant treatment before elective surgery. Follow-up visits were conducted on the preoperative day before elective surgery, POD2, POD14, and POD30, with an evaluation of adverse events, impact on elective surgery, clinical examination, and quality of recovery.

RESULTS

Endoscopic calcium electroporation was performed as an outpatient procedure in all 21 cases, with no procedure-related complications reported. At follow-up, five adverse events were registered, two of which were classified as serious adverse events. Surgery was performed as planned in 19 patients (median time to surgery, 8 days), and the final two patients underwent surgery with a delay due to adverse events (14 and 33 days). No significant impact on the quality of recovery scores nor inflammatory markers were seen before and after calcium electroporation, nor baseline and POD30.

CONCLUSIONS

Endoscopic calcium electroporation is a safe and feasible procedure in patients with potentially curable CRC. The study showed limited side effects and limited impact on the following elective surgical resection.

NETosis: Sculpting tumor metastasis and immunotherapy

The process of neutrophil extracellular traps (NETs) formation, called NETosis, is a peculiar death modality of neutrophils, which was first observed as an immune response against bacterial infection. However, recent work has revealed the unique biology of NETosis in facilitating tumor metastatic process. Neutrophil extracellular traps released by the tumor microenvironment (TME) shield tumor cells from cytotoxic immunity, leading to impaired tumor clearance. Besides, tumor cells tapped by NETs enable to travel through vessels and subsequently seed distant organs. Targeted ablation of NETosis has been proven to be beneficial in potentiating the efficacy of cancer immunotherapy in the metastatic settings. This review outlines the impact of NETosis at almost all stages of tumor metastasis. Furthermore, understanding the multifaceted interplay between NETosis and the TME components is crucial for supporting the rational development of highly effective combination immunotherapeutic strategies with anti-NETosis for patients with metastatic disease.

Is cancer an intelligent species?

Some relevant emerging properties of intelligent systems are "adaptation to a changing environment," "reaction to unexpected situations," "capacity of problem solving," and "ability to communicate." Single cells have remarkable abilities to adapt, make adequate context-dependent decision, take constructive actions, and communicate, thus theoretically meeting all the above-mentioned requirements. From a biological point of view, cancer can be viewed as an invasive species, composed of cells that move from primary to distant sites, being continuously exposed to changes in the environmental conditions. Blood represents the first hostile habitat that a cancer cell encounters once detached from the primary site, so that cancer cells must rapidly carry out multiple adaptation strategies to survive. The aim of this review was to deepen the adaptation mechanisms of cancer cells in the blood microenvironment, particularly referring to four adaptation strategies typical of animal species (phenotypic adaptation, metabolic adaptation, niche adaptation, and collective adaptation), which together define the broad concept of biological intelligence. We provided evidence that the required adaptations (either structural, metabolic, and related to metastatic niche formation) and "social" behavior are useful principles allowing putting into a coherent frame many features of circulating cancer cells. This interpretative frame is described by the comparison with analog behavioral traits typical of various animal models.

Influence of the Anesthetic Technique on Circulating Extracellular Vesicles in Bladder Cancer Patients Undergoing Radical Cystectomy: A Prospective, Randomized Trial

Anesthetics have been shown to alter tumor progression and seem to influence surgical cancer outcome. Circulating extracellular vesicles as mediators of intercellular communication are involved in cancer progression and may be influenced by anesthetics. In this prospective, randomized study, effects of anesthetics on extracellular vesicles and associated micro-RNAs in bladder cancer patients undergoing radical cystectomy were tested. Extracellular vesicles from 51 patients at four perioperative time points receiving Propofol or Sevoflurane were extracted with polymer-based methods and quantified with a nanoparticle-tracking analysis. Vesicle-associated micro-RNAs were analyzed with a real-time polymerase chain reaction using array cards and single assays for tumor-associated miR-21-5p, miR-15a-5p, miR-17-5p and miR-451a. Plasma extracellular vesicle concentration (suture: fold change (fc) in Propofol at 4.1 ± 3.9 vs. Sevoflurane at 0.8 ± 0.5; p = 0.003) and associated miRNAs increased significantly (+30% post induction, +9% 30 Min surgery) in the Propofol group. Tumor-associated miRNAs increased during surgery in both groups (fc in miR-21-5p: 24.3 ± 10.2, p = 0.029; fc in miR-15a-5p: 9.7 ± 3.8, p = 0.027; fc in miR-17-5p: 5.4 ± 1.7, p = 0.014), whereas antitumor miR-451a increased in the Propofol group only (fc: 2.5 ± 0.6 vs. 1.0 ± 0.2; p = 0.022). Anesthetics influence extracellular vesicles and associated micro-RNAs of bladder cancer patients during surgery. Increased expression of antitumor micro-RNA may be an explanatory approach for decreased tumor cell viability after Propofol.

The impacts of exosomes on bone metastatic progression and their potential clinical utility

Bone is one of the most common sites of cancer metastasis. Once cancer metastasizes to the bone, the mortality rate of cancer patients dramatically increases. Although the exact mechanisms for this observation remain elusive, recent studies have revealed that the complex crosstalk between bone marrow microenvironment and bone metastatic cancer cells is responsible for the induction of treatment resistance. Consequently, bone metastasis is currently considered incurable. Bone metastasis not only impairs the patients' survival, but also negatively affects their quality of life by causing painful complications. It has recently been implicated the regulatory role of exosomes in cancer development and/or progression as a delivery biomaterial between cancer cells and tumor microenvironment. However, little is known as to how exosomes contribute to the progression of bone metastasis by impaction on the crosstalk between bone metastatic cancer cells and bone marrow microenvironment. Here, we highlighted the emerging roles of cancer-derived exosomes in (i) the process of dissemination and bone colonization of bone metastatic cancer cells, (ii) the enhancement of crosstalk between bone marrow microenvironment and bone metastatic cancer cells, (iii) the development of its resultant painful complications, and (iv) the clinical applications of exosomes in the bone metastatic setting.

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Cancer-derived exosomes facilitate cancer dissemination and colonization to bone.

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Cancer-derived exosomes are crucial for controlling bone metastatic phenotype.

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Cancer-derived exosomes prime bone marrow microenvironment for further metastasis.

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Cancer-derived exosomes are involved in development of cancer-induced bone pain.

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Exosomes can be used as therapies and/or diagnostic tools for bone metastasis.

Neoadjuvant chemotherapy in patients undergoing colonic resection for locally advanced nonmetastatic colon cancer: A nationwide propensity score matched cohort study

AIM

Neoadjuvant chemotherapy (NCT) for nonmetastatic colon cancer is not routinely used, and is currently only recommended as a treatment option for a subgroup of patients with T4b colon cancers in clinical guidelines. However, NCT may cause downstaging of the tumour, increase resectability, eradicate micrometastases and thereby improve long-term outcomes for patients with nonmetastatic colon cancer. The aim of this study was to investigate the short-term postoperative outcomes in a nationwide cohort of patients with locally advanced colon cancer (LACC) receiving NCT.

METHOD

Using the Danish Colorectal Cancer Group Database, data were retrieved on patients diagnosed with LACC (defined as clinical T3 with extramural tumour invasion >5 mm or T4) and treated with resection with a curative intent between 2015 and 2019. Propensity score matching (PSM) in a 1:1 ratio was performed to compare short-term surgical and oncological outcomes in patients receiving NCT with patients operated on without receiving NCT.

RESULTS

A total of 179 LACC patients were treated with NCT and 1131 were not. After PSM, 145 patients remained in each group. We found no significant differences in any short-term postoperative outcomes between the two groups. We found significant differences in favour of NCT regarding radicality and pathological N category [86% vs. 81% R0 (P = 0.029) and 51% vs. 46% pN0 (P = 0.017), respectively].

CONCLUSION

Neoadjuvant chemotherapy for LACC does not result in worse short-term postoperative outcomes and may increase the R0 rate as well as node-negative disease. Results on long-term benefits including survival are awaited from several ongoing randomized controlled trials.

Cancer Stem Cells and Circulatory Tumor Cells Promote Breast Cancer Metastasis

Breast cancer (BC) is a highly metastatic, pathological cancer that significantly affects women worldwide. The mortality rate of BC is related to its heterogeneity, aggressive phenotype, and metastasis. Recent studies have highlighted that the tumor microenvironment (TME) is critical for the interplay between metastasis mediators in BC. BC stem cells, tumor-derived exosomes, circulatory tumor cells (CTCs), and signaling pathways dynamically remodel the TME and promote metastasis. This review examines the cellular and molecular mechanisms governing the epithelial to mesenchymal transition (EMT) that facilitate metastasis. This review also discusses the role of cancer stem cells (CSCs), tumor-derived exosomes, and CTs in promoting BC metastasis. Furthermore, the review emphasizes major signaling pathways that mediate metastasis in BC. Finally, the interplay among CSCs, exosomes, and CTCs in mediating metastasis have been highlighted. Therefore, understanding the molecular cues that mediate the association of CSCs, exosomes, and CTCs in TME helps to optimize systemic therapy to target metastatic BC.

Molecular and Immune Phenotypic Modifications during Metastatic Dissemination in Lung Carcinogenesis

Simple Summary

Metastatic cancer is a multifaceted complex disease. It is mainly characterized by a strong invasive potential, metastasis, resistance to therapy, and poor clinical prognosis. Although the use of immune checkpoint inhibitors (ICI) has substantially improved cancer treatment and therapy, there are many significant challenges to be addressed. In this review, we provide an overview of the mechanisms used by metastatic or disseminating tumor cells (DTCs) in order to understand cancer progression to metastasis, and establish new strategies for novel therapeutic interventions.

Abstract

The tumor microenvironment plays a key role in the progression of lung tumorigenesis, progression, and metastasis. Recent data reveal that disseminated tumor cells (DTCs) appear to play a key role in the development and progression of lung neoplasiaby driving immune system dysfunction and established immunosuppression, which is vital for evading the host immune response. As a consequence, in this review we will discuss the role and function of DTCs in immune cell signaling routes which trigger drug resistance and immunosuppression. We will also discuss the metabolic biology of DTCs, their dormancy, and their plasticity, which are critical for metastasis and drive lung tumor progression. Furthermore, we will consider the crosstalk between DTCs and myeloid cells in tumor-related immunosuppression. Specifically, we will investigate the molecular immune-related mechanisms in the tumor microenvironment that lead to decreased drug sensitivity and tumor relapse, along with strategies for reversing drug resistance and targeting immunosuppressive tumor networks. Deciphering these molecular mechanisms is essential for preclinical and clinical investigations in order to enhance therapeutic efficacy. Furthermore, a better understanding of these immune cell signaling pathways that drive immune surveillance, immune-driven inflammation, and tumor-related immunosuppression is necessary for future personalized therapeutic approaches.

Molecular Mechanisms and Cellular Contribution from Lung Fibrosis to Lung Cancer Development

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease (ILD) of unknown aetiology, with a median survival of 2-4 years from the time of diagnosis. Although IPF has unknown aetiology by definition, there have been identified several risks factors increasing the probability of the onset and progression of the disease in IPF patients such as cigarette smoking and environmental risk factors associated with domestic and occupational exposure. Among them, cigarette smoking together with concomitant emphysema might predispose IPF patients to lung cancer (LC), mostly to non-small cell lung cancer (NSCLC), increasing the risk of lung cancer development. To this purpose, IPF and LC share several cellular and molecular processes driving the progression of both pathologies such as fibroblast transition proliferation and activation, endoplasmic reticulum stress, oxidative stress, and many genetic and epigenetic markers that predispose IPF patients to LC development. Nintedanib, a tyrosine-kinase inhibitor, was firstly developed as an anticancer drug and then recognized as an anti-fibrotic agent based on the common target molecular pathway. In this review our aim is to describe the updated studies on common cellular and molecular mechanisms between IPF and lung cancer, knowledge of which might help to find novel therapeutic targets for this disease combination.

Natural Killer Cells in Cancer and Cancer Immunotherapy

The detection and killing of neoplastic cells require coordination of a variety of antitumor effector cells. Natural killer (NK) cells of the innate immune system are at the forefront of the body's defense systems and evidence suggests that the infiltration and cytotoxicity of NK cells in the cancer tissue influence treatment efficacy and survival. As powerful effectors in the anticancer immune response, NK cells rapidly recognize and kill transformed cells with little reactivity against healthy self-tissues, which highlights their potential role in cancer immunotherapy. Modern immunotherapeutic approaches include immune checkpoint inhibitors to revitalize dysfunctional T cells and adoptive cell transfer using CD8⁺ T cells with chimeric antigen receptors to enhance their functionality. However, treatment responses may be short-lived and risk of discontinuation due to adverse effects necessitates the development of safer immuno-oncologic therapies with improved outcomes. To this end, novel combinatorial interventions using T cells and NK cells and strategies for overcoming associated challenges are currently being investigated. This review summarizes the advances in the research on NK cells in cancer and cancer immunotherapy and discusses the possible implications for future cancer treatment.

Cancer: a mirrored room between tumor bulk and tumor microenvironment

It has been well documented that the tumor microenvironment (TME) plays a key role in the promotion of drug resistance, the support of tumor progression, invasiveness, metastasis, and even the maintenance of a cancer stem-like phenotype. Here, we reviewed TME formation presenting it as a reflection of a tumor’s own organization during the different stages of tumor development. Interestingly, functionally different groups of stromal cells seem to have specific spatial distributions within the TME that change as the tumor evolves into advanced stage progression which correlates with the fact that cancer stem-like cells (CSCs) are located in the edges of solid tumor masses in advanced tumors.

We also focus on the continuos feedback that is established between a tumor and its surroundings. The “talk” between tumor mass cells and TME stromal cells, marks the evolution of both interlocuting cell types. For instance, the metabolic and functional transformations that stromal cells undergo due to tumor corrupting activity.

Moreover, the molecular basis of metastatic spread is also approached, making special emphasis on the site-specific pre-metastatic niche formation as another reflection of the primary tumor molecular signature.

Finally, several therapeutic approaches targeting primary TME and pre-metastatic niche are suggested. For instance, a systematic analysis of the TME just adjacent to the tumor mass to establish the proportion of myofibroblasts-like cancer-associated fibroblasts (CAFs) which may in turn correspond to stemness and metastases-promotion. Or the implementation of “re-education” therapies consisting of switching tumor-supportive stromal cells into tumor-suppressive ones. In summary, to improve our clinical management of cancer, it is crucial to understand and learn how to manage the close interaction between TME and metastasis.

Cancer-Associated Fibroblasts and Tumor-Associated Macrophages in Cancer and Cancer Immunotherapy

Our understanding of the tumor microenvironment (TME), including the interplay between tumor cells, stromal cells, immune cells, and extracellular matrix components, is mandatory for the innovation of new therapeutic approaches in cancer. The cell-cell communication within the TME plays a pivotal role in the evolution and progression of cancer. Cancer-associated fibroblasts (CAF) and tumor-associated macrophages (TAM) are major cell populations in the stroma of all solid tumors and often exert protumorigenic functions; however, the origin and precise functions of CAF and TAM are still incompletely understood. CAF and TAM hold significant potential as therapeutic targets to improve outcomes in oncology when combined with existing therapies. The regulation of CAF/TAM communication and/or their differentiation could be of high impact for improving the future targeted treatment strategies. Nevertheless, there is much scope for research and innovation in this field with regards to the development of novel drugs. In this review, we elaborate on the current knowledge on CAF and TAM in cancer and cancer immunotherapy. Additionally, by focusing on their heterogenous functions in different stages and types of cancer, we explore their role as potential therapeutic targets and highlight certain aspects of their functions that need further research.

Clinical Implications of Exosomes: Targeted Drug Delivery for Cancer Treatment

Exosomes are nanoscale vesicles generated by cells for intercellular communication. Due to their composition, significant research has been conducted to transform these particles into specific delivery systems for various disease states. In this review, we discuss the common isolation and loading methods of exosomes, some of the major roles of exosomes in the tumor microenvironment, as well as discuss recent applications of exosomes as drug delivery vessels and the resulting clinical implications.

Rationale for Early Detection of EWSR1 Translocation-Associated Sarcoma Biomarkers in Liquid Biopsy

Sarcomas are mesenchymal tumours that often arise and develop as a result of chromosomal translocations, and for several forms of sarcoma the EWSR1 gene is a frequent translocation partner. Sarcomas are a rare form of malignancy, which arguably have a proportionally greater societal burden that their prevalence would suggest, as they are more common in young people, with survivors prone to lifelong disability. For most forms of sarcoma, histological diagnosis is confirmed by molecular techniques such as FISH or RT-PCR. Surveillance after surgical excision, or ablation by radiation or chemotherapy, has remained relatively unchanged for decades, but recent developments in molecular biology have accelerated the progress towards routine analysis of liquid biopsies of peripheral blood. The potential to detect evidence of residual disease or metastasis in the blood has been demonstrated by several groups but remains unrealized as a routine diagnostic for relapse during remission, for disease monitoring during treatment, and for the detection of occult, residual disease at the end of therapy. An update is provided on research relevant to the improvement of the early detection of relapse in sarcomas with EWSR1-associated translocations, in the contexts of biology, diagnosis, and liquid biopsy.

Anesthesia Options and the Recurrence of Cancer: What We Know so Far?

Surgery is a critical period in the survival of patients with cancer. While resective surgery of primary tumors has shown to prolong the life of these patients, it can also promote mechanisms associated with metastatic progression. During surgery, patients require general and sometimes local anesthetics that also modulate mechanisms that can favor or reduce metastasis. In this narrative review, we summarized the evidence about the impact of local, regional and general anesthesia on metastatic mechanisms and the survival of patients. The available evidence suggests that cancer recurrence is not significantly impacted by neither regional anesthesia nor volatile or total intravenous anesthesia.

Molecular principles of metastasis: a hallmark of cancer revisited

Metastasis is the hallmark of cancer that is responsible for the greatest number of cancer-related deaths. Yet, it remains poorly understood. The continuous evolution of cancer biology research and the emergence of new paradigms in the study of metastasis have revealed some of the molecular underpinnings of this dissemination process. The invading tumor cell, on its way to the target site, interacts with other proteins and cells. Recognition of these interactions improved the understanding of some of the biological principles of the metastatic cell that govern its mobility and plasticity. Communication with the tumor microenvironment allows invading cancer cells to overcome stromal challenges, settle, and colonize. These characteristics of cancer cells are driven by genetic and epigenetic modifications within the tumor cell itself and its microenvironment. Establishing the biological mechanisms of the metastatic process is crucial in finding open therapeutic windows for successful interventions. In this review, the authors explore the recent advancements in the field of metastasis and highlight the latest insights that contribute to shaping this hallmark of cancer.