Nerve fibers in the tumor microenvironment in neurotropic cancer-pancreatic cancer and cholangiocarcinoma

Application of imaging technology for the diagnosis of malignancy in the pancreaticobiliary duodenal junction (Review)

The pancreaticobiliary duodenal junction (PBDJ) is the connecting area of the pancreatic duct, bile duct and duodenum. In a broad sense, it refers to a region formed by the head of the pancreas, the pancreatic segment of the common bile duct and the intraduodenal segment, the descending and the horizontal part of the duodenum, and the soft tissue around the pancreatic head. In a narrow sense, it refers to the anatomical Vater ampulla. Due to its complex and variable anatomical features, and the diversity of pathological changes, it is challenging to make an early diagnosis of malignancy at the PBDJ and define the histological type. The unique anatomical structure of this area may be the basis for the occurrence of malignant tumors. Therefore, understanding and subclassifying the anatomical configuration of the PBDJ is of great significance for the prevention and treatment of malignant tumors at their source. The present review comprehensively discusses commonly used imaging techniques and other new technologies for diagnosing malignancy at the PBDJ, offering evidence for physicians and patients to select appropriate examination methods.

Neural Circuitries between the Brain and Peripheral Solid Tumors

The recent discovery of the pivotal role of the central nervous system in controlling tumor initiation and progression has opened a new field of research. Increasing evidence suggests a bidirectional interaction between the brain and tumors. The brain influences the biological behavior of tumor cells through complex neural networks involving the peripheral nervous system, the endocrine system, and the immune system, whereas tumors can establish local autonomic and sensory neural networks to transmit signals into the central nervous system, thereby affecting brain activity. This review aims to summarize the latest research in brain-tumor cross-talk, exploring neural circuitries between the brain and various peripheral solid tumors, analyzing the roles in tumor development and the related molecular mediators and pathologic mechanisms, and highlighting the critical impact on the understanding of cancer biology. Enhanced understanding of reciprocal communication between the brain and tumors will establish a solid theoretical basis for further research and could open avenues for repurposing psychiatric interventions in cancer treatment.

Neuroscience of cancer: Research progress and emerging of the field

Cancer cells immediately expand and penetrate adjoining tissues, as opposed to metastasis, that is the spread of cancer cells through the circulatory or lymphatic systems to more distant places via the invasion process. We found that a lack of studies discussed tumor development with the nervous system, by the aspects of cancer-tissue invasion (biological) and chemical modulation of growth that cascades by releasing neural-related factors from the nerve endings via chemical substances known as neurotransmitters. In this review, we aimed to carefully demonstrate and describe the cancer invasion and interaction with the nervous system, as well as reveal the research progress and the emerging neuroscience of cancer. An initial set of 160 references underwent systematic review and summarization. Through a meticulous screening process, these data were refined, ultimately leading to the inclusion of 98 studies that adhered to predetermined criteria. The outcomes show that one formidable challenge in the realm of cancer lies in its intrinsic heterogeneity and remarkable capacity for rapid adaptation. Despite advancements in genomics and precision medicine, there is still a need to identify new molecular targets. Considering cancer within its molecular and cellular environment, including neural components, is crucial for addressing this challenge. In conclusion, this review provides good referential data for direct, indirect, biological, and chemical interaction for nerve tissue-tumor interaction, suggesting the establishment of new therapy techniques and mechanisms by controlling and modifying neuron networks that supply signals to tumors.

Hallmarks of perineural invasion in pancreatic ductal adenocarcinoma: new biological dimensions

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor with a high metastatic potential. Perineural invasion (PNI) occurs in the early stages of PDAC with a high incidence rate and is directly associated with a poor prognosis. It involves close interaction among PDAC cells, nerves and the tumor microenvironment. In this review, we detailed discuss PNI-related pain, six specific steps of PNI, and treatment of PDAC with PNI and emphasize the importance of novel technologies for further investigation.

γ-aminobutyric acid receptor B signaling drives glioblastoma in females in an immune-dependent manner

Sex differences in immune responses impact cancer outcomes and treatment response, including in glioblastoma (GBM). However, host factors underlying sex specific immune-cancer interactions are poorly understood. Here, we identify the neurotransmitter γ-aminobutyric acid (GABA) as a driver of GBM-promoting immune response in females. We demonstrated that GABA receptor B (GABBR) signaling enhances L-Arginine metabolism and nitric oxide synthase 2 (NOS2) expression in female granulocytic myeloid-derived suppressor cells (gMDSCs). GABBR agonist and GABA analog promoted GBM growth in females in an immune-dependent manner, while GABBR inhibition reduces gMDSC NOS2 production and extends survival only in females. Furthermore, female GBM patients have enriched GABA transcriptional signatures compared to males, and the use of GABA analogs in GBM patients is associated with worse short-term outcomes only in females. Collectively, these results highlight that GABA modulates anti-tumor immune response in a sex-specific manner, supporting future assessment of GABA pathway inhibitors as part of immunotherapy approaches.

Neurotransmitters: Impressive regulators of tumor progression

In contemporary times, tumors have emerged as the primary cause of mortality in the global population. Ongoing research has shed light on the significance of neurotransmitters in the regulation of tumors. It has been established that neurotransmitters play a pivotal role in tumor cell angiogenesis by triggering the transformation of stromal cells into tumor cells, modulating receptors on tumor stem cells, and even inducing immunosuppression. These actions ultimately foster the proliferation and metastasis of tumor cells. Several major neurotransmitters have been found to exert modulatory effects on tumor cells, including the ability to restrict emergency hematopoiesis and bind to receptors on the postsynaptic membrane, thereby inhibiting malignant progression. The abnormal secretion of neurotransmitters is closely associated with tumor progression, suggesting that focusing on neurotransmitters may yield unexpected breakthroughs in tumor therapy. This article presents an analysis and outlook on the potential of targeting neurotransmitters in tumor therapy.

The Crosstalk between Nerves and Cancer-A Poorly Understood Phenomenon and New Possibilities

INTRODUCTION

Crosstalk occurs between nerve and cancer cells. These interactions are important for cancer homeostasis and metabolism. Nerve cells influence the tumor microenvironment (TME) and participate in metastasis through neurogenesis, neural extension, and axonogenesis. We summarized the past and current literature on the interaction between nerves and cancer, with a special focus on pancreatic ductal adenocarcinoma (PDAC), prostate cancer (PCa), and the role of the nerve growth factor (NGF) in cancer.

MATERIALS/METHODS

We reviewed PubMed and Google Scholar for the relevant literature on the relationship between nerves, neurotrophins, and cancer in general and specifically for both PCa and PDAC.

RESULTS

The NGF helped sustain cancer cell proliferation and evade immune defense. It is a neuropeptide involved in neurogenic inflammation through the activation of several cells of the immune system by several proinflammatory cytokines. Both PCa and PDAC employ different strategies to evade immune defense. The prostate is richly innervated by both the sympathetic and parasympathetic nerves, which helps in both growth control and homeostasis. Newly formed autonomic nerve fibers grow into cancer cells and contribute to cancer initiation and progression through the activation of β-adrenergic and muscarinic cholinergic signaling. Surgical or chemical sympathectomy prevents the development of prostate cancer. Beta-blockers have a high therapeutic potential for cancer, although current clinical data have been contradictory. With a better understanding of the beta-receptors, one could identify specific receptors that could have an effect on prostate cancer development or act as therapeutic agents.

CONCLUSION

The bidirectional crosstalk between the nervous system and cancer cells has emerged as a crucial regulator of cancer and its microenvironment. Denervation has been shown to be promising in vitro and in animal models. Additionally, there is a potential relationship between cancer and psychosocial biology through neurotransmitters and neurotrophins.

Cholinergic Mechanisms in Gastrointestinal Neoplasia

Acetylcholine-activated receptors are divided broadly into two major structurally distinct classes: ligand-gated ion channel nicotinic and G-protein-coupled muscarinic receptors. Each class encompasses several structurally related receptor subtypes with distinct patterns of tissue expression and post-receptor signal transduction mechanisms. The activation of both nicotinic and muscarinic cholinergic receptors has been associated with the induction and progression of gastrointestinal neoplasia. Herein, after briefly reviewing the classification of acetylcholine-activated receptors and the role that nicotinic and muscarinic cholinergic signaling plays in normal digestive function, we consider the mechanics of acetylcholine synthesis and release by neuronal and non-neuronal cells in the gastrointestinal microenvironment, and current methodology and challenges in measuring serum and tissue acetylcholine levels accurately. Then, we critically evaluate the evidence that constitutive and ligand-induced activation of acetylcholine-activated receptors plays a role in promoting gastrointestinal neoplasia. We focus primarily on adenocarcinomas of the stomach, pancreas, and colon, because these cancers are particularly common worldwide and, when diagnosed at an advanced stage, are associated with very high rates of morbidity and mortality. Throughout this comprehensive review, we concentrate on identifying novel ways to leverage these observations for prognostic and therapeutic purposes.

The coexistence of myosteatosis and the creatinine/cystatin C ratio are determinants of outcomes in cholangiocarcinoma patients undergoing curative surgery

Background

Myosteatosis is a well-established predictor of poor prognosis in many types of cancer, and a decreased Creatinine/Cystatin C ratio (CCR) is a known indicator of unfavorable outcomes in patients with metabolic disorders and cancer. Despite this knowledge, the significance of concurrent CCR and myosteatosis in predicting the prognosis of patients with cholangiocarcinoma (CCA) who undergo radical surgery remains uncertain.

Method

Data from 757 patients with cholangiocarcinoma who underwent the first radical resection in the Affiliated Hospital of Qingdao University from January 2017 to March 2022 were collected. According to the inclusion and exclusion criteria, 149 patients were finally included in the retrospective study cohort. Various clinicopathological, serological, and radiological data were collected at admission. Myosteatosis was evaluated using sliceOmatic software on computed tomography (CT) images. The study used receiver operating characteristic (ROC) curve analysis to determine the critical value of CCR, which predicts overall survival (OS) based on the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were employed to identify the risk factors associated with OS and RFS confidently.

Results

The group identified as the myosteatosis cohort consisted of 79 patients with an average age of 64.3 ± 7.8 years. The ROC curve analysis revealed an optimal critical CCR value of 10.834. A low CCR ≤ 10.834 and myosteatosis were found to be associated with poor OS and RFS outcomes (P = 0.022; P = 0.017; P = 0.038; P = 0.030 respectively). Moreover, patients with myosteatosis and a CCR ≤ 10.834 had the worst OS and RFS outcomes (P = 0.035; P = 0.027).

Conclusion

After radical excision in CCA patients, the presence of myosteatosis and CCR had a negative correlation with prognosis. A more accurate prediction of OS and RFS was possible by combining CCR and myosteatosis, compared to CCR alone.

Cellular interactions in tumor microenvironment during breast cancer progression: new frontiers and implications for novel therapeutics

The breast cancer tumor microenvironment (TME) is dynamic, with various immune and non-immune cells interacting to regulate tumor progression and anti-tumor immunity. It is now evident that the cells within the TME significantly contribute to breast cancer progression and resistance to various conventional and newly developed anti-tumor therapies. Both immune and non-immune cells in the TME play critical roles in tumor onset, uncontrolled proliferation, metastasis, immune evasion, and resistance to anti-tumor therapies. Consequently, molecular and cellular components of breast TME have emerged as promising therapeutic targets for developing novel treatments. The breast TME primarily comprises cancer cells, stromal cells, vasculature, and infiltrating immune cells. Currently, numerous clinical trials targeting specific TME components of breast cancer are underway. However, the complexity of the TME and its impact on the evasion of anti-tumor immunity necessitate further research to develop novel and improved breast cancer therapies. The multifaceted nature of breast TME cells arises from their phenotypic and functional plasticity, which endows them with both pro and anti-tumor roles during tumor progression. In this review, we discuss current understanding and recent advances in the pro and anti-tumoral functions of TME cells and their implications for developing safe and effective therapies to control breast cancer progress.

Cholangiocarcinoma Malignant Traits Are Promoted by Schwann Cells through TGFβ Signaling in a Model of Perineural Invasion

The term cholangiocarcinoma (CCA) defines a class of epithelial malignancies originating from bile ducts. Although it has been demonstrated that CCA patients with perineural invasion (PNI) have a worse prognosis, the biological features of this phenomenon are yet unclear. Our data show that in human intrahepatic CCA specimens with documented PNI, nerve-infiltrating CCA cells display positivity of the epithelial marker cytokeratin 7, lower with respect to the rest of the tumor mass. In an in vitro 3D model, CCA cells move towards a peripheral nerve explant allowing contact with Schwann cells (SCs) emerging from the nerve. Here, we show that SCs produce soluble factors that favor the migration, invasion, survival and proliferation of CCA cells in vitro. This effect is accompanied by a cadherin switch, suggestive of an epithelial-mesenchymal transition. The influence of SCs in promoting the ability of CCA cells to migrate and invade the extracellular matrix is hampered by a specific TGFβ receptor 1 (TGFBR1) antagonist. Differential proteomic data indicate that the exposure of CCA cells to SC secreted factors induces the upregulation of key oncogenes and the concomitant downregulation of some tumor suppressors. Taken together, these data concur in identifying SCs as possible promoters of a more aggressive CCA phenotype, ascribing a central role to TGFβ signaling in regulating this process.

Survival analysis of laparoscopic surgery and open surgery for hilar cholangiocarcinoma: a retrospective cohort study

BACKGROUND/PURPOSE

This study compared the clinical efficacy and safety of laparoscopic versus open resection for hilar cholangiocarcinoma (HCCA) and analyzed potential prognostic factors.

METHODS

The study included patients who underwent HCCA resection at our center from March 2012 to February 2022. Perioperative complications and postoperative prognosis were compared between the laparoscopic surgery (LS) and open surgery (OS) groups.

RESULTS

After screening 313 HCCA patients, 68 patients were eligible for the study in the LS group (n = 40) and OS group (n = 28). Kaplan-Meier survival curve analysis revealed that overall survival > 2 years and 3-year disease-free survival (DFS) were more common in the LS than OS group, but the rate of 2-year DFS was lower in the LS group than OS group. Cox multivariate regression analysis revealed age (< 65 years), radical resection, and postoperative adjuvant therapy were associated with reduced risk of death (hazard ratio [HR] = 0.380, 95% confidence interval [CI] = 0.150-0.940, P = 0.036; HR = 0.080, 95% CI = 0.010-0.710, P = 0.024 and HR = 0.380, 95% CI = 0.150-0.960, P = 0.040), whereas preoperative biliary drainage was an independent factor associated with increased risk of death (HR = 2.810, 95% CI = 1.130-6.950, P = 0.026). Perineuronal invasion was identified as an independent risk factor affecting DFS (HR = 5.180, 95% CI = 1.170-22.960, P = 0.030).

CONCLUSIONS

Compared with OS, laparoscopic HCCA resection does not significantly differ in terms of clinical efficacy. Age (<65 years), radical resection, and postoperative adjuvant therapy reduce the risk of death, and preoperative biliary drainage increases the risk of death.

Noninvasive prediction of perineural invasion in intrahepatic cholangiocarcinoma by clinicoradiological features and computed tomography radiomics based on interpretable machine learning: a multicenter cohort study

BACKGROUND

Perineural invasion (PNI) of intrahepatic cholangiocarcinoma (ICC) is a strong independent risk factor for tumour recurrence and long-term patient survival. However, there is a lack of noninvasive tools for accurately predicting the PNI status. The authors develop and validate a combined model incorporating radiomics signature and clinicoradiological features based on machine learning for predicting PNI in ICC, and used the Shapley Additive explanation (SHAP) to visualize the prediction process for clinical application.

METHODS

This retrospective and prospective study included 243 patients with pathologically diagnosed ICC (training, n =136; external validation, n =81; prospective, n =26, respectively) who underwent preoperative contrast-enhanced computed tomography between January 2012 and May 2023 at three institutions (three tertiary referral centres in Guangdong Province, China). The ElasticNet was applied to select radiomics features and construct signature derived from computed tomography images, and univariate and multivariate analyses by logistic regression were used to identify the significant clinical and radiological variables with PNI. A robust combined model incorporating radiomics signature and clinicoradiological features based on machine learning was developed and the SHAP was used to visualize the prediction process. A Kaplan-Meier survival analysis was performed to compare prognostic differences between PNI-positive and PNI-negative groups and was conducted to explore the prognostic information of the combined model.

RESULTS

Among 243 patients (mean age, 61.2 years ± 11.0 (SD); 152 men and 91 women), 108 (44.4%) were diagnosed as PNI-positive. The radiomics signature was constructed by seven radiomics features, with areas under the curves of 0.792, 0.748, and 0.729 in the training, external validation, and prospective cohorts, respectively. Three significant clinicoradiological features were selected and combined with radiomics signature to construct a combined model using machine learning. The eXtreme Gradient Boosting exhibited improved accuracy and robustness (areas under the curves of 0.884, 0.831, and 0.831, respectively). Survival analysis showed the construction combined model could be used to stratify relapse-free survival (hazard ratio, 1.933; 95% CI: 1.093-3.418; P =0.021).

CONCLUSIONS

We developed and validated a robust combined model incorporating radiomics signature and clinicoradiological features based on machine learning to accurately identify the PNI statuses of ICC, and visualize the prediction process through SHAP for clinical application.

The significance of peri-neural invasion in patients with resected hilar cholangiocarcinoma: A single-center experience in China

BACKGROUND

The significance of peri-neural invasion (PNI) in resected patients with hilar cholangiocarcinoma (HCCA) has been rarely explored. Our study was performed to evaluate the significance of PNI in resected HCCA patients in terms of tumor biological features and long-term survival.

METHODS

We retrospectively reviewed surgically-treated HCCA patients between June, 2000 and June 2018. SPSS 25.0 software was used for statistical analysis.

RESULTS

A total of 239 resected HCCA patients were included (No. PNI: 138). PNI indicated more aggressive tumor biological features. Major vascular reconstruction was more frequently performed in patients with PNI (34.8% vs 24.8%, P = 0.064). Patients with PNI shared a significantly higher percentage of surgical margin width <5 mm (29.0% vs 16.8%, P = 0.02). The proportion of patients with T1-2 disease (31.2% vs 40.6%, P = 0.085) or I-II disease (21% vs 34.7%, P = 0.014) was significantly lower in patients with PNI. The overall morbidity rate was significantly higher in patients with PNI (P = 0.042). A much worse overall survival (OS) (P = 0.0003) or disease-free survival (DFS) (P = 0.0011) in patients with PNI. Even after matching vital prognostic factors, a significantly worse OS (P = 0.0003) or DFS (P = 0.0002) was still observed in patients with PNI. PNI was an independent prognostic factor in both OS (P = 0.011) and DFS (P = 0.024).

CONCLUSION

PNI indicated more aggressive tumor biological features and more advanced tumor stage in patients with resected HCCA. PNI can be an independent prognostic factor in both OS and DFS. Future multi-center studies covering various races or populations are required for further validation.

The immunological landscape in pancreatic ductal adenocarcinoma and overcoming resistance to immunotherapy

Pancreatic ductal adenocarcinoma is associated with a poor prognosis and there are few treatment options. The development of immunotherapy in pancreatic ductal adenocarcinoma has been difficult, and immune checkpoint inhibitors are only effective in a very small subset of patients. Most obstacles for treatment have been related to intertumoural and intratumoural heterogeneity, the composition of tumour stroma, and crosstalk with cancer cells. Improved molecular characterisation of pancreatic ductal adenocarcinoma and a better understanding of its microenvironment have paved the way for novel immunotherapy strategies, including the identification of predictive biomarkers, the development of rational combinations to optimise effectiveness, and the targeting of new mechanisms. Future immunotherapy strategies should consider individual characteristics to move beyond the traditional immune targets and circumvent the resistance to therapies that have been developed so far.

Immune evasion on the nanoscale: Small extracellular vesicles in pancreatic ductal adenocarcinoma immunity

Pancreatic ductal adenocarcinoma (PDAC) is a type of cancer alarmingly expanding in our modern societies that is still proving to be very challenging to counteract. This disease constitutes a quintessential example of the multiple interactions existing between the tumour and its surrounding microenvironment. In particular, PDAC is characterized by a very immunosuppressive environment that favours cancer growth and makes this cancer type very resistant to immunotherapy. The primary tumour releases many factors that influence both the microenvironment and the immune landscape. Extracellular vesicles (EVs), recently identified as indispensable entities ensuring cell-to-cell communication in both physiological and pathological processes, seem to play a pivotal function in ensuring the delivery of these factors to the tumour-surrounding tissues. In this review, we summarize the present understanding on the crosstalk among tumour cells and the cellular immune microenvironment emphasizing the pro-malignant role played by extracellular vesicles. We also discuss how a greater knowledge of the roles of EVs in tumour immune escape could be translated into clinical applications.

Targeting the Cancer-Neuronal Crosstalk in the Pancreatic Cancer Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) represents one of the most aggressive solid tumors with a dismal prognosis and an increasing incidence. At the time of diagnosis, more than 85% of patients are in an unresectable stage. For these patients, chemotherapy can prolong survival by only a few months. Unfortunately, in recent decades, no groundbreaking therapies have emerged for PDAC, thus raising the question of how to identify novel therapeutic druggable targets to improve prognosis. Recently, the tumor microenvironment and especially its neural component has gained increasing interest in the pancreatic cancer field. A histological hallmark of PDAC is perineural invasion (PNI), whereby cancer cells invade surrounding nerves, providing an alternative route for metastatic spread. The extent of PNI has been positively correlated with early tumor recurrence and reduced overall survival. Multiple studies have shown that mechanisms involved in PNI are also involved in tumor spread and pain generation. Targeting these pathways has shown promising results in alleviating pain and reducing PNI in preclinical models. In this review, we will describe the mechanisms and future treatment strategies to target this mutually trophic interaction between cancer cells to open novel avenues for the treatment of patients diagnosed with PDAC.

Assessment of the level III of Inoue by preoperative endoscopic ultrasound and elastography: a novel approach to predict a periarterial divestment technique in borderline resectable (BR) or locally advanced (LA) pancreatic adenocarcinoma-How I do it

BACKGROUND

Periarterial divestment is a surgical technique to approach borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC) with arterial involvement. There are no reports in the literature regarding the role of endoscopic ultrasound and elastography (EUS-EG) in exploring the integrity of Inoue's level III and its correlation with the periarterial divestment technique feasibility. Our research is aimed at exploring the role of EUS-EG in this scenario.

METHODS

We describe our approach to Inoue's level II by EUS-EG in patients with BR and LA pancreatic cancer patients after neoadjuvant chemotherapy.

RESULTS

Between June 2019 and December 2020, four patients out of 25 were eligible to perform a preoperative EUS-EG. In all cases, Inoue's level III integrity was corroborated by EUS-EG and confirmed posteriorly in the surgical scenario where a periarterial divestment technique was feasible. Vein resections were necessary in all cases, with no need for arterial resection. An R0 (> 1 mm) margin was achieved in all patients, and the histopathological assessment showed the presence of neurovascular tissue at the peripheral arterial margin.

CONCLUSION

Preoperatively, EUS-EG is a novel approach to explore the integrity of Inoue's level III and could be helpful to preclude a periarterial divestment technique in borderline resectable or locally advanced pancreatic adenocarcinoma with arterial involvement.

Quantification of perineural invasion in pancreatic ductal adenocarcinoma: proposal of a severity score system

Perineural invasion (PNI) is a common feature in pancreatic ductal adenocarcinoma (PDAC) and correlates with an aggressive tumor behavior already at early stages of disease. PNI is currently considered as a "present vs. absent" feature, and a severity score system has not yet been established. The aim of the present study was thus to develop and validate a score system for PNI and to correlate it with other prognostic features. In this monocentric retrospective study, 356 consecutive PDAC patients (61.8% upfront surgery patients, 38.2% received neoadjuvant therapy) were analyzed. PNI was scored as follows: 0: absent; 1: the presence of neoplasia along nerves < 3 mm in caliber; and 2: neoplastic infiltration of nerve fibers ≥ 3 mm and/or massive perineural infiltration and/or the presence of necrosis of the infiltrated nerve bundle. For every PNI grade, the correlation with other pathological features, disease-free survival (DFS), and disease-specific survival (DSS) were analyzed. Uni- and multivariate analysis for DFS and DSS were also performed. PNI was found in 72.5% of the patients. Relevant trends between PNI score and tumor differentiation grade, lymph node metastases, vascular invasion, and surgical margins status were found. The latter was the only parameter statistically correlated with the proposed score. The agreement between pathologists was substantial (Cohen's K 0.61). PNI severity score significantly correlated also with decreased DFS and DSS at univariate analysis (p < 0.001). At multivariate analysis, only the presence of lymph node metastases was an independent predictor of DFS (HR 2.235 p < 0.001). Lymph node metastases (HR 2.902, p < 0.001) and tumor differentiation grade (HR 1.677, p = 0.002) were independent predictors of DSS. Our newly developed PNI score correlates with other features of PDAC aggressiveness and proved to have a prognostic role though less robust than lymph nodes metastases and tumor differentiation grade. A prospective validation is needed.

Radical Tumor Denervation Activates Potent Local and Global Cancer Treatment

This preliminary study seeks to determine the effect of R&P denervation on tumor growth and survival in immunocompetent rats bearing an aggressive and metastatic breast solid tumor. A novel microsurgical approach was applied "in situ", aiming to induce R&P denervation through the division of every single nerve fiber connecting the host with the primary tumor via its complete detachment and re-attachment, by resecting and reconnecting its supplying artery and vein (anastomosis). This preparation, known as microsurgical graft or flap, is radically denervated by definition, but also effectively delays or even impedes the return of innervation for a significant period of time, thus creating a critical and therapeutic time window. Mammary adenocarcinoma cells (HH-16.cl4) were injected into immunocompetent Sprague Dawley adult rats. When the tumors reached a certain volume, the subjects entered the study. The primary tumor, including a substantial amount of peritumoral tissue, was surgically isolated on a dominant artery and vein, which was resected and reconnected using a surgical microscope (orthotopic tumor auto-transplantation). Intending to simulate metastasis, two or three tumors were simultaneously implanted and only one was treated, using the surgical technique described herein. Primary tumor regression was observed in all of the microsurgically treated subjects, associated with a potent systemic anticancer effect and prolonged survival. In stark contrast, the subjects received a close to identical surgical operation; however, with the intact neurovascular connection, they did not achieve the therapeutic result. Animals bearing multiple tumors and receiving the same treatment in only one tumor exhibited regression in both the "primary" and remote- untreated tumors at a clinically significant percentage, with regression occurring in more than half of the treated subjects. A novel therapeutic approach is presented, which induces the permanent regression of primary and, notably, remote tumors, as well as, evidently, the naturally occurring metastatic lesions, at a high rate. This strategy is aligned with the impetus that comes from the current translational research data, focusing on the abrogation of the neuro-tumoral interaction as an alternative treatment strategy. More data regarding the clinical significance of this are expected to come up from a pilot clinical trial that is ongoing.

Inflammation induced by tumor-associated nerves promotes resistance to anti-PD-1 therapy in cancer patients and is targetable by interleukin-6 blockade

While the nervous system has reciprocal interactions with both cancer and the immune system, little is known about the potential role of tumor associated nerves (TANs) in modulating anti-tumoral immunity. Moreover, while peri-neural invasion is a well establish poor prognostic factor across cancer types, the mechanisms driving this clinical effect remain unknown. Here, we provide clinical and mechniastic association between TANs damage and resistance to anti-PD-1 therapy. Using electron microscopy, electrical conduction studies, and tumor samples of cutaneous squamous cell carcinoma (cSCC) patients, we showed that cancer cells can destroy myelin sheath and induce TANs degeneration. Multi-omics and spatial analyses of tumor samples from cSCC patients who underwent neoadjuvant anti-PD-1 therapy demonstrated that anti-PD-1 non-responders had higher rates of peri-neural invasion, TANs damage and degeneration compared to responders, both at baseline and following neoadjuvant treatment. Tumors from non-responders were also characterized by a sustained signaling of interferon type I (IFN-I) - known to both propagate nerve degeneration and to dampen anti-tumoral immunity. Peri-neural niches of non-responders were characterized by higher immune activity compared to responders, including immune-suppressive activity of M2 macrophages, and T regulatory cells. This tumor promoting inflammation expanded to the rest of the tumor microenvironment in non-responders. Anti-PD-1 efficacy was dampened by inducing nerve damage prior to treatment administration in a murine model. In contrast, anti-PD-1 efficacy was enhanced by denervation and by interleukin-6 blockade. These findings suggested a potential novel anti-PD-1 resistance drived by TANs damage and inflammation. This resistance mechanism is targetable and may have therapeutic implications in other neurotropic cancers with poor response to anti-PD-1 therapy such as pancreatic, prostate, and breast cancers.

The significance of peri-neural invasion in patients with gallbladder carcinoma after curative surgery: a 10 year experience in China

The significance of peri-neural invasion (PNI) in patients with gallbladder carcinoma (GBC) after curative surgery remains unknown. Current study was performed to evaluate the significance of PNI in resected GBC patients in terms of tumor-related biological features and long-term survival. Patients with GBC between September 2010 and September 2020 were reviewed and analyzed. SPSS 25.0 software were used for statistical analysis. A total of 324 resected GBC patients were identified (No. PNI: 64). An elevated preoperative Ca19.9 level (P = 0.001), obstructive jaundice (P = 0.001), liver invasion (P < 0.0001), lymph-vascular invasion (P < 0.0001), lymph-node metastasis (P < 0.0001), and poor or moderate differentiation status (P = 0.036) were more frequently detected in patients with PNI. Major hepatectomy (P = 0.019), bile duct resection (P < 0.0001), combined multi-visceral resections (P = 0.001), and combined major vascular resections and reconstructions (P = 0.002) were also more frequently detected. However, a significantly lower R0 rate (P < 0.0001) was acquired in patients with PNI. Patients with PNI were generally more advanced disease and shared a much worse prognosis even after matching. PNI was an independent prognostic factor of disease-free survival as well as an independent predictor of early recurrence. Postoperative adjuvant chemotherapy has brought an obvious survival benefit in resected GBC patients with PNI. PNI could be regarded as an indicator of worse prognosis and could serve as an independent predictor of early recurrence. Postoperative adjuvant chemotherapy was correlated with an improved survival for resected GBC patients with PNI. Upcoming multicenter studies covering various races are warranted for further validation.

Perineural Invasion of Pancreatic Ductal Adenocarcinoma is Associated with Early Recurrence after Neoadjuvant Therapy Followed by Resection

BACKGROUND

Neoadjuvant therapy (NAT) is increasingly utilized in the treatment of pancreatic ductal adenocarcinoma (PDAC). However, there are limited data on risk factors and patterns of recurrence after surgical resection. This study aimed to analyze timing and recurrence patterns of PDAC after NAT followed by curative resection.

METHODS

The medical charts of patients with PDAC treated with NAT followed by curative-intent surgical resection at a single health system from January 1, 2012 to January 1, 2020 were retrospectively reviewed. Early recurrence was defined as recurrence within 12 months of surgical resection.

RESULTS

91 patients were included and median follow up was 20.1 months. Recurrence occurred in 50 (55%) patients, with median recurrence free survival (RFS) of 11.9 months. Overall, 18 (36%) patients had local and 32 (64%) had distant recurrences. Median RFS and overall survival (OS) between local and distant recurrence were similar. Perineural invasion (PNI) and the presence of a T2 + tumor was significantly higher in recurrence group than in no recurrence group. PNI was a significant risk factor for early recurrence.

CONCLUSION

After NAT and surgical resection of PDAC, disease recurrence was common, with distant metastasis being the most common. PNI was significantly higher in the recurrence group.

In Vitro Effects of Photon Beam and Carbon Ion Radiotherapy on the Perineural Invasion of Two Cell Lines of Neurotropic Tumours

Primary mucosal melanoma (PMM) and pancreatic ductal adenocarcinoma (PDAC) are two aggressive malignancies, characterized by intrinsic radio-chemoresistance and neurotropism, a histological feature resulting in frequent perineural invasion (PNI), supported by neurotrophic factors secreted in the tumour microenvironment (TME), such as neurotrophin-3 (NT-3). Carbon-ion radiotherapy (CIRT) could represent an effective option in unresectable PMM and PDAC. Only a few data about the effects of CIRT on PNI in relation to NT-3 are available in the literature, despite the numerous pieces of evidence revealing the peculiar effects of this type of radiation on tumour cell migration. This in vitro study investigated for the first time the response of PMM and PDAC cells to NT-3 and evaluated the effects of conventional photon beam radiotherapy (XRT) and CIRT on cell viability, proliferation, and migration. Our results demonstrated the greater capacity of C-ions to generally decrease cell viability, proliferation, and migration, while the addition of NT-3 after both types of irradiation determined an increase in these features, maintaining a dose-dependent trend and acting more effectively as a chemoattractant than inductor in the case of migration.

Important Cells and Factors from Tumor Microenvironment Participated in Perineural Invasion

Perineural invasion (PNI) as the fourth way for solid tumors metastasis and invasion has attracted a lot of attention, recent research reported a new point that PNI starts to include axon growth and possible nerve "invasion" to tumors as the component. More and more tumor-nerve crosstalk has been explored to explain the internal mechanism for tumor microenvironment (TME) of some types of tumors tends to observe nerve infiltration. As is well known, the interaction of tumor cells, peripheral blood vessels, extracellular matrix, other non-malignant cells, and signal molecules in TME plays a key role in the occurrence, development, and metastasis of cancer, as to the occurrence and development of PNI. We aim to summarize the current theories on the molecular mediators and pathogenesis of PNI, add the latest scientific research progress, and explore the use of single-cell spatial transcriptomics in this invasion way. A better understanding of PNI may help to understand tumor metastasis and recurrence and will be beneficial for improving staging strategies, new treatment methods, and even paradigm shifts in our treatment of patients.

Genetic Contribution of the Adrenergic, Cholinergic, and Serotonergic Systems to Leiomyoma Development and Treatment

The link between the autonomic nervous system and tumor biology is being unfold. We aim to study the contribution of genes of the adrenergic (ADBR2 - rs1042713, NM_000024.6:c.46G>A, NP_000015.2:p. Gly16Arg), cholinergic (CHRNA5 - rs16969968, NM_000745.3:c.1192G>A, NP_000736.2:p.Asp398Asn), and serotonergic systems (SLC6A4 - 5-HTTVNTR-intron2, HTR2A - rs6313, NM_000621.5:c.102C>T, NP_ 001365853 .1: p. Ser 34=) to gynecological tumorigenesis and their treatment by embolization. A total of 517 DNA samples from women were analyzed. Samples were genotyped by PCR, PCR-RFLP and EndPoint genotyping. Results show a statistically significant association between the AA genotype of the ADBR2 gene and GG genotype of the CHRNA5 gene with leiomyoma (OR = 2.311; p = 0.003 and OR = 2.165; p = 0.001, respectively), and the epistatic interaction between genotypes increases the risk (OR = 2.458; p= 0.043). The GG genotype (CHRNA5) shows a lower reduction of the volume of the main leiomyoma after treatment (p=0.015). Combination of the genotypes 12/12-AA (SLC6A4 - ADBR2) increases the risk to leiomyoma (OR = 2.540, p= 0.030). TT genotype of HTR2A gene in combination with any of the two risk genotypes (of ADBR2 or CHRNA5) increases substantially the risk (OR = 5.266, p = 0.006; OR = 6.364, p=0.007, respectively). We conclude that ADBR2 and CHRNA5 genes have a relevant role that is enhanced by the epistatic relationship with the genes HTR2A and SLC6A4. CHRNA5 gene may also be a modulator of the success of embolization. We confirm the contribution of the genetics of Autonomous Nervous System to tumor biology.

The connection between innervation and metabolic rearrangements in pancreatic cancer through serine

Pancreatic cancer is a kind of aggressive tumor famous for its lethality and intractability, and pancreatic ductal adenocarcinoma is the most common type. Patients with pancreatic cancer often suffer a rapid loss of weight and abdominal neuropathic pain in their early stages and then go through cachexia in the advanced stage. These features of patients are considered to be related to metabolic reprogramming of pancreatic cancer and abundant nerve innervation responsible for the pain. With increasing literature certifying the relationship between nerves and pancreatic ductal adenocarcinoma (PDAC), more evidence point out that innervation's role is not limited to neuropathic pain but explore its anti/pro-tumor functions in PDAC, especially the neural-metabolic crosstalks. This review aims to unite pancreatic cancer's innervation and metabolic rearrangements with terminated published articles. Hopefully, this article could explore the pathogenesis of PDAC and further promote promising detecting or therapeutic measurements for PDAC according to the lavish innervation in PDAC.

The clinical implications and molecular features of intrahepatic cholangiocarcinoma with perineural invasion

BACKGROUND

Perineural invasion (PNI) is associated with metastasis in malignancies, including intrahepatic cholangiocarcinoma (ICC), and is correlated with poor prognosis.

METHODS

The study included three large cohorts: ZS-ICC and TMA cohorts from our team, MSK cohort from a public database, and a small cohort named cohort 4. Prognostic implications of PNI were investigated in MSK cohort and TMA cohort. PNI-related genomic and transcriptomic profiles were analyzed in MSK and ZS-ICC cohorts. GO, KEGG, and ssGSEA analyses were performed. Immunohistochemistry was used to investigate the relationship between PNI and markers of neurons, hydrolases, and immune cells. The efficacy of adjuvant therapy in ICC patients with PNI was also assessed.

RESULTS

A total of 30.6% and 20.7% ICC patients had PNI in MSK and TMA cohorts respectively. Patients with PNI presented with malignant phenotypes such as high CA19-9, the large bile duct type, lymph node invasion, and shortened overall survival (OS) and relapse-free survival (RFS). Nerves involved in PNI positively express tyrosine hydroxylase (TH), a marker of sympathetic nerves. Patients with PNI showed high mutation frequency of KRAS and an immune suppressive metastasis prone niche of decreased NK cell, increased neutrophil, and elevated PD-L1, CD80, and CD86 expression. Patients with PNI had an extended OS after adjuvant therapy with TEGIO, GEMOX, or capecitabine.

CONCLUSION

Our study deciphered the genomic features and the immune suppressive metastasis-prone niche in ICC with PNI. Patients with PNI showed a poor prognosis after surgery but a good response to adjuvant chemotherapy.

Risk factors of positive resection margin differ in pancreaticoduodenectomy and distal pancreatosplenectomy for pancreatic ductal adenocarcinoma undergoing upfront surgery

OBJECTIVE

Positive resection margin indicates worse prognosis. The present study identified the independent risk factors of R1 resection in pancreaticoduodenectomy (PD) and distal pancreatosplenectomy (DP) for patients with pancreatic ductal adenocarcinoma (PDAC).

METHOD

Consecutive patients who were operated from 1st December 2017 to 30th December 2018 were analyzed retrospectively. A standardized pathological examination with digital whole-mount slide images (DWMSIs) was utilized for evaluation of resection margin status. R1 was defined as microscopic tumor infiltration within 1 mm to the resection margin. The potential risk factors of R1 resection for PD and DP were analyzed separately by univariate and multivariate logistic regression analyses.

RESULTS

For the 192 patients who underwent PD, and the 87 patients who underwent DP, the R1 resection rates were 31.8% and 35.6%, respectively. Univariate analysis on risk factors of R1 resection for PD were tumor location, lymphovascular invasion, N staging, and TNM staging; while those for DP were T staging and TNM staging. Multivariate logistic regression analysis showed the location of tumor in the neck and uncinate process, and N1/2 staging were independent risk factors of R1 resection for PD; while those for DP were T3 staging.

CONCLUSIONS

The clarification of the risk factors of R1 resection might clearly make surgeons take reasonable decisions on surgical strategies for different surgical procedures in patients with PDAC, so as to obtain the first attempt of R0 resection.

Low Complement Factor H-Related 3 (CFHR3) Expression Indicates Poor Prognosis and Immune Regulation in Cholangiocarcinoma

Background

Cholangiocarcinoma (CCA) is a cancerous tumor that leads to a high rate of morbidity and death. Complement factor H-related 3 (CFHR3) is a gene belonging to the CFHR gene family. In this study, we investigated the usefulness of CFHR3 in the diagnostic stage and CCA prognosis prediction. In the interim, we looked at its coexpressed genes and their roles. The correlation between CFHR3 and immunological infiltration was also investigated.

Methods

The expression of the genes data and the clinical information were obtained from the databases of The Cancer Genome Atlas (TCGA) together with the Gene Expression Omnibus (GEO). The crucial gene was found to be the overlapping gene in the two databases. The area under the curve (AUC) and the Kaplan-Meier survival curve were used to describe the usefulness of the predictive prognosis of CCA patients. Univariate regression analysis and multivariate survival analysis were performed to find the independent prognosis factors. The PPI network was constructed based on the STRING database, and the coexpression approach was utilized in predicting the coexpression genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were also performed to identify the related functions. Additionally, the probable mechanism of the important gene was examined using gene set enrichment analysis (GSEA). The correlation between CFHR3 and immune infiltration was discovered using TIMER. The LncACTdb 3.0 database was used to analyze the location of CFHR3 in the cell. The cBioPortal database was used to find the mutation in CFHR3.

Results

TCGA datasets and GEO datasets revealed an elevated expression level of CFHR3 in normal tissues as well as a lower expression level in cholangiocarcinoma tissues in the present research. The low expression level of CFHR3 was related to an unfavorable prognosis. Using CFHR3 expression in diagnosis and predicting the patient prognosis (AUC = 1.000) is valuable. Using the CFHR3 gene and a time-lapse prediction, we could estimate survival rates over 1, 2, and 3 years. The AUC values were more than 0.6(AUC = 0.808; 0.760; 0.711). Functional enrichment analysis revealed a substantial correlation between this signature and complement and coagulation cascades. The same outcomes from GSEA were achieved. We found the key gene widely exists in the nucleus, exosomes, and cytoplasm of normal cells using the LncACTdb 3.0 database. In immune regulation analysis, we identified that the expression level of CFHR3 had a positive correlation with infiltrating levels of B cells, neutrophils, and macrophages, but correlated negatively with cholangiocarcinoma cells, CD8+ T cells, and monocytes.

The Role of Nerve Fibers in the Tumor Immune Microenvironment of Solid Tumors

The importance of neurons and nerve fibers in the tumor microenvironment (TME) of solid tumors is now acknowledged after being unexplored for a long time; this is possible due to the development of new technologies that allow in situ characterization of the TME. Recent studies have shown that the density and types of nerves that innervate tumors can predict a patient's clinical outcome and drive several processes of tumor biology. Nowadays, several efforts in cancer research and neuroscience are taking place to elucidate the mechanisms that drive tumor-associated innervation and nerve-tumor and nerve-immune interaction. Assessment of neurons and nerves within the context of the TME can be performed in situ, in tumor tissue, using several pathology-based strategies that utilize histochemical and immunohistochemistry principles, hi-plex technologies, and computational pathology approaches to identify measurable histopathological characteristics of nerves. These features include the number and type of tumor associated nerves, topographical location and microenvironment of neural invasion of malignant cells, and investigation of neuro-related biomarker expression in nerves, tumor cells, and cells of the TME. A deeper understanding of these complex interactions and the impact of nerves in tumor biology will guide the design of better strategies for targeted therapy in clinical trials.

Emerging Roles of the Nervous System in Gastrointestinal Cancer Development

Simple Summary

Nerve–cancer cross-talk has increasingly become a focus of the oncology field, particularly in gastrointestinal (GI) cancers. The indispensable roles of the nervous system in GI tumorigenesis and malignancy have been dissected by epidemiological, experimental animal and mechanistic data. Herein, we review and integrate recent discoveries linking the nervous system to GI cancer initiation and progression, and focus on the molecular mechanisms by which nerves and neural receptor pathways drive GI malignancy.

Abstract

Our understanding of the fascinating connection between nervous system and gastrointestinal (GI) tumorigenesis has expanded greatly in recent years. Recent studies revealed that neurogenesis plays an active part in GI tumor initiation and progression. Tumor-driven neurogenesis, as well as neurite outgrowth of the pre-existing peripheral nervous system (PNS), may fuel GI tumor progression via facilitating cancer cell proliferation, chemoresistance, invasion and immune escape. Neurotransmitters and neuropeptides drive the activation of various oncogenic pathways downstream of neural receptors within cancer cells, underscoring the importance of neural signaling pathways in GI tumor malignancy. In addition, neural infiltration also plays an integral role in tumor microenvironments, and contributes to an environment in favor of tumor angiogenesis, immune evasion and invasion. Blockade of tumor innervation via denervation or pharmacological agents may serve as a promising therapeutic strategy against GI tumors. In this review, we summarize recent findings linking the nervous system to GI tumor progression, set the spotlight on the molecular mechanisms by which neural signaling fuels cancer aggressiveness, and highlight the importance of targeting neural mechanisms in GI tumor therapy.

Challenges and Opportunities for Immunoprofiling Using a Spatial High-Plex Technology: The NanoString GeoMx® Digital Spatial Profiler

Characterization of the tumor microenvironment through immunoprofiling has become an essential resource for the understanding of the complex immune cell interactions and the assessment of biomarkers for prognosis and prediction of immunotherapy response; however, these studies are often limited by tissue heterogeneity and sample size. The nanoString GeoMx^® Digital Spatial Profiler (DSP) is a platform that allows high-plex profiling at the protein and RNA level, providing spatial and temporal assessment of tumors in frozen or formalin-fixed paraffin-embedded limited tissue sample. Recently, high-impact studies have shown the feasibility of using this technology to identify biomarkers in different settings, including predictive biomarkers for immunotherapy in different tumor types. These studies showed that compared to other multiplex and high-plex platforms, the DSP can interrogate a higher number of biomarkers with higher throughput; however, it does not provide single-cell resolution, including co-expression of biomarker or spatial information at the single-cell level. In this review, we will describe the technical overview of the platform, present current evidence of the advantages and limitations of the applications of this technology, and provide important considerations for the experimental design for translational immune-oncology research using this tissue-based high-plex profiling approach.

Identification of a neural development gene expression signature in colon cancer stem cells reveals a role for EGR2 in tumorigenesis

Recent evidence demonstrates that colon cancer stem cells (CSCs) can generate neurons that synapse with tumor innervating fibers required for tumorigenesis and disease progression. Greater understanding of the mechanisms that regulate CSC driven tumor neurogenesis may therefore lead to more effective treatments. RNA-sequencing analyses of ALDHPositive CSCs from colon cancer patient-derived organoids (PDOs) and xenografts (PDXs) showed CSCs to be enriched for neural development genes. Functional analyses of genes differentially expressed in CSCs from PDO and PDX models demonstrated the neural crest stem cell (NCSC) regulator EGR2 to be required for tumor growth and to control expression of homebox superfamily embryonic master transcriptional regulator HOX genes and the neural stem cell and master cell fate regulator SOX2. These data support CSCs as the source of tumor neurogenesis and suggest that targeting EGR2 may provide a therapeutic differentiation strategy to eliminate CSCs and block nervous system driven disease progression.

Identification of prognostic genes in the pancreatic adenocarcinoma immune microenvironment by integrated bioinformatics analysis

PURPOSE

Pancreatic adenocarcinoma (PAAD) is one of the most common causes of death among solid tumors, and its pathogenesis remains to be clarified. This study aims to elucidate the value of immune/stromal-related genes in the prognosis of PAAD through comprehensive bioinformatics analysis based on the immune microenvironment and validated in Chinese pancreatic cancer patients.

METHODS

Gene expression profiles of pancreatic cancer patients were obtained from TCGA database. Differentially expressed genes (DEGs) were identified based on the ESTIMATE algorithm. Gene co-expression networks were constructed using WGCNA. In the key module, survival analysis was used to reveal the prognostic value. Subsequently, we performed functional enrichment analysis to construct a protein-protein interaction (PPI) network. The relationship between tumor immune infiltration and hub genes was analyzed by TIMER and CIBERSORT. Finally, it was validated in the GEO database and in tissues of Chinese pancreatic cancer patients.

RESULTS

In the TCGA pancreatic cancer cohort, a low immune/stromal score was associated with a good prognosis. After bioinformatic analysis, 57 genes were identified to be significantly associated with pancreatic cancer prognosis. Among them, up-regulation of four genes (COL6A3, PLAU, MMP11 and MMP14) indicated poor prognosis and was associated with multiple immune cell infiltration. IHC results showed that PLAU protein levels from Chinese pancreatic cancer tissues were significantly higher than those from adjacent non-tumor tissues and were also associated with tumor TNM stage and lymph node metastasis.

CONCLUSION

In conclusion, this study demonstrates that PLAU may serve as a new diagnostic and therapeutic target, which is highly expressed in Chinese pancreatic cancer tissues and associated with lymph node metastasis.

Tumour invasion and dissemination

Activating invasion and metastasis are one of the primary hallmarks of cancer, the latter representing the leading cause of death in cancer patients. Whilst many advances in this area have been made in recent years, the process of cancer dissemination and the underlying mechanisms governing invasion are still poorly understood. Cancer cells exhibit multiple invasion strategies, including switching between modes of invasion and plasticity in response to therapies, surgical interventions and environmental stimuli. The ability of cancer cells to switch migratory modes and their inherent plasticity highlights the critical challenge preventing the successful design of cancer and anti-metastatic therapies. This mini-review presents current knowledge on the critical models of tumour invasion and dissemination. We also discuss the current issues surrounding current treatments and arising therapeutic opportunities. We propose that the establishment of novel approaches to study the key biological mechanisms underlying the metastatic cascade is critical in finding novel targets that could ultimately lead to complete inhibition of cancer cell invasion and dissemination.

Limitations of Nerve Fiber Density as a Prognostic Marker in Predicting Oncological Outcomes in Hepatocellular Carcinoma

It has been shown that the presence and density of nerve fibers (NFs; NFD) in the tumor microenvironment (TME) may play an important prognostic role in predicting long-term oncological outcomes in various malignancies. However, the role of NFD in the prognosis of hepatocellular carcinoma (HCC) is yet to be explored. To this end, we aimed to investigate the impact of NFs on oncological outcomes in a large European single-center cohort of HCC patients. In total, 153 HCC patients who underwent partial hepatectomy in a curative-intent setting between 2010 and 2021 at our university hospital were included in this study. Group comparisons between patients with and without NFs were conducted and the association of recurrence-free survival (RFS) and overall survival (OS) with the presence of NFs and other clinico-pathological variables were determined by univariate and multivariable Cox regression models. Patients with NFs in the TME presented with a median OS of 66 months (95% CI: 30−102) compared to 42 months (95% CI: 20−63) for patients without NFs (p = 0.804 log-rank). Further, RFS was 26 months (95% CI: 12−40) for patients with NFs compared to 18 months (95% CI: 9−27) for patients without NFs (p = 0.666 log-rank). In a subgroup analysis, patients with NFD ≤ 5 showed a median OS of 54 months (95% CI: 11−97) compared to 48 months (95% CI: 0−106) for the group of patients with NFD > 5 (p = 0.787 log-rank). Correspondingly, the RFS was 26 months (95% CI: 10−42) in patients with NFD ≤ 5 and 29 months (95% CI: 14−44) for the subcohort with NFD > 5 (p = 0.421 log-rank). Further, group comparisons showed no clinico-pathological differences between patients with NFs (n = 76) and without NFs (n = 77) and NFs were not associated with OS (p = 0.806) and RFS (p = 0.322) in our Cox regression models. In contrast to observations in various malignancies, NFs in the TME and NFD are not associated with long-term oncological outcomes in HCC patients undergoing surgery.

Characteristic of Perineural Invasion in Hilar Cholangiocarcinoma Based on Whole-Mount Histologic Large Sections of Liver

Background & Objective

Perineural invasion is an important biological feature of hilar cholangiocarcinoma (HCCA). We developed a whole-mount histologic large sections (WHLS) of the liver to evaluate peripheral nerve invasion (PNI) of HCCA.

Methods

Using sampling, fixation, dehydration, embedding, sectioning, hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining, and scanning, the characteristics of intrahepatic and extrahepatic PNI in 20 patients with Bismuth type III and type IV HCCA were analyzed with WHLS. Correlation between the characteristics of nerve invasion and tumor size, vascular invasion (artery, portal vein), degree of differentiation, microvascular invasion (MVI), carbohydrate antigen19-9 (CA19-9), and differentiation degree of HCCA was statistically evaluated.

Results

The WHLS of the liver was successfully established, which enabled us to observe intrahepatic and extrahepatic distribution of HCCA and whether surrounding tissues including nervous, blood, and lymph vessels were infiltrated. Extrahepatic and intrahepatic PNI were identified in 20 (100%) patients and 1 (5.0%) patient, respectively. Vessel density decreased in most invaded nerves presented by CD-34, which correlated with 100% of poorly differentiated and 83% of moderately differentiated tumors (P<0.008).

Conclusion

This study established a WHLS of the liver that can be used for clinical diagnosis and research, and confirmed that extrahepatic PNI is prevalent, but intrahepatic nerve invasion is rare and does not accompany the invasion scope of bile ducts in types III and IV HCCA. In addition, moderately and poorly differentiated malignant tumors are more prone to PNI, independent of blood supply.

Targeting tumor innervation: premises, promises, and challenges

A high intratumoral nerve density is correlated with poor survival, high metastasis, and high recurrence across multiple solid tumor types. Recent research has revealed that cancer cells release diverse neurotrophic factors and exosomes to promote tumor innervation, in addition, infiltrating nerves can also mediate multiple tumor biological processes via exosomes and neurotransmitters. In this review, through seminal studies establishing tumor innervation, we discuss the communication between peripheral nerves and tumor cells in the tumor microenvironment (TME), and revealed the nerve-tumor regulation mechanisms on oncogenic process, angiogenesis, lymphangiogenesis, and immunity. Finally, we discussed the promising directions of ‘old drugs newly used’ to target TME communication and clarified a new line to prevent tumor malignant capacity.

Emerging experimental models for assessing perineural invasion in human cancers

Cancer neuroscience has emerged as a burgeoning field for the investigation of cancer-nervous system interactions. Perineural invasion (PNI) is defined as the presence of cancer cells that surround and/or invade the nerves infiltrating the tumor microenvironment. PNI is closely associated with increased tumor recurrence and diminished survival in many cancer types. Based on diverse in vitro, ex vivo, and in vivo models, mounting evidence suggests that the reciprocal crosstalk between nerves and cancer cells drives PNI, which is mediated by several factors including secreted neurotrophins, chemokines, exosomes, and inflammatory cells. Typical in vitro models using dorsal root ganglia (DRG) cells cocultured with cancer cells or other cell types allow the study of isolated factors. Ex vivo PNI models created by cocultivating cancer cells with explanted vagus and sciatic nerves enable the study of neuroaffinity in a time-saving and cost-efficient manner. In vivo models such as genetically engineered mouse models (GEMMs) and the chicken embryo chorioallantoic membrane (CAM)-DRG model, provide the nerve microenvironment needed to recapitulate the complex pathophysiological processes of PNI. Here, we summarize the current methods commonly used for modeling PNI and discuss the inherent pros and cons of these approaches for understanding PNI biology.

Nanoemulsion-Assisted siRNA Delivery to Modulate the Nervous Tumor Microenvironment in the Treatment of Pancreatic Cancer

Pancreatic cancer (PC) is a fatal human cancer, whose progression is highly dependent on the nervous tumor microenvironment. In the present study, cationic perfluorocarbon nanoemulsions were employed as an intraperitoneal delivery platform to facilitate the delivery and penetration of a therapeutic small interfering RNA (siRNA) to orthotopic pancreatic tumors. The nanoemulsion was used to silence the expression of the nerve growth factor (NGF) as a way of favorably modulating the tumor-neuronal interactions in pancreatic tumors. The nanoemulsions exhibited deep tumor penetration that was dependent on exocytosis and enhanced NGF gene silencing in vitro and in vivo when compared with control polycation/siRNA polyplexes, leading to the effective and safe suppression of tumor growth in orthotopic PC. Overall, emulsion-assisted delivery of NGF siRNA is a promising treatment approach for PC by targeting the interactions between the tumor cells and the nervous microenvironment.

Schwann Cells in Digestive System Disorders

Proper functioning of the digestive system is ensured by coordinated action of the central and peripheral nervous systems (PNS). Peripheral innervation of the digestive system can be viewed as intrinsic and extrinsic. The intrinsic portion is mainly composed of the neurons and glia of the enteric nervous system (ENS), while the extrinsic part is formed by sympathetic, parasympathetic, and sensory branches of the PNS. Glial cells are a crucial component of digestive tract innervation, and a great deal of research evidence highlights the important status of ENS glia in health and disease. In this review, we shift the focus a bit and discuss the functions of Schwann cells (SCs), the glial cells of the extrinsic innervation of the digestive system. For more context, we also provide information on the basic findings regarding the function of innervation in disorders of the digestive organs. We find diverse SC roles described particularly in the mouth, the pancreas, and the intestine. We note that most of the scientific evidence concerns the involvement of SCs in cancer progression and pain, but some research identifies stem cell functions and potential for regenerative medicine.

Schwann Cells in the Tumor Microenvironment: Need More Attention

The tumor microenvironment (TME), which is composed of various cell components and signaling molecules, plays an important role in the occurrence and progression of tumors and has become the central issue of current cancer research. In recent years, as a part of the TME, the peripheral nervous system (PNS) has attracted increasing attention. Moreover, emerging evidence shows that Schwann cells (SCs), which are the most important glial cells in the PNS, are not simply spectators in the TME. In this review article, we focused on the up-to-date research progress on SCs in the TME and introduced our point of view. In detail, we described that under two main tumor-nerve interaction patterns, perineural invasion (PNI) and tumor innervation, SCs were reprogrammed and acted as important participants. We also investigated the newest mechanisms between the interactions of SCs and tumor cells. In addition, SCs can have profound impacts on other cellular components in the TME, such as immune cells and cancer-associated fibroblasts (CAFs), involving immune regulation, tumor-related pain, and nerve remodeling. Overall, these innovative statements can expand the scope of the TME, help fully understand the significant role of SCs in the tumor-nerve-immune axis, and propose enlightenments to innovate antitumor therapeutic methods and future research.

Mast Cell–Tumor Interactions: Molecular Mechanisms of Recruitment, Intratumoral Communication and Potential Therapeutic Targets for Tumor Growth

Mast cells (MCs) are tissue-resident immune cells that are important players in diseases associated with chronic inflammation such as cancer. Since MCs can infiltrate solid tumors and promote or limit tumor growth, a possible polarization of MCs to pro-tumoral or anti-tumoral phenotypes has been proposed and remains as a challenging research field. Here, we review the recent evidence regarding the complex relationship between MCs and tumor cells. In particular, we consider: (1) the multifaceted role of MCs on tumor growth suggested by histological analysis of tumor biopsies and studies performed in MC-deficient animal models; (2) the signaling pathways triggered by tumor-derived chemotactic mediators and bioactive lipids that promote MC migration and modulate their function inside tumors; (3) the possible phenotypic changes on MCs triggered by prevalent conditions in the tumor microenvironment (TME) such as hypoxia; (4) the signaling pathways that specifically lead to the production of angiogenic factors, mainly VEGF; and (5) the possible role of MCs on tumor fibrosis and metastasis. Finally, we discuss the novel literature on the molecular mechanisms potentially related to phenotypic changes that MCs undergo into the TME and some therapeutic strategies targeting MC activation to limit tumor growth.

Worst Pattern of Perineural Invasion Redefines the Spatial Localization of Nerves in Oral Squamous Cell Carcinoma

As a key histopathological characteristic of tumor invasion, perineural invasion (PNI) assists tumor dissemination, whereas the current definition of PNI by dichotomy is not accurate and the prognostic value of PNI has not reached consensus. To define PNI status in each patient when mixed types of PNI occurred simultaneously, we here further subclassified the traditional PNI in 183 patients with oral squamous cell carcinoma (OSCC). The spatial localization of nerves in OSCC microenvironment was thoroughly evaluated and successfully concluded into four types of PNI: 0, tumor cells away from nerves; 1, tumor cells encircling nerves less than 33%; 2, tumor cells encircling nerves at least 33%; and 3, tumor cells infiltrating into nerve sheathes. Sequentially, patients were stratified by single and mixed types of PNI. Traditionally, types 0 and 1 were defined as PNI^-, while types 2 and 3 were PNI⁺, which predicted shorter survival time. When multiple types of PNI existed within one tumor, patients with higher score of PNI types tended to have a relatively worse prognosis. Therefore, to define the status of PNI more precisely, the new variable worst pattern of PNI (WPNI) was proposed, which was taken as the highest score of PNI types present in each patient no matter how focal. Results showed that patients with WPNI 1 had longest survival time, and WPNI 2 correlated with better overall survival (p = 0.02), local-regional recurrence-free survival (p = 0.03), and distant metastasis-free survival (p = 0.046) than WPNI 3. Multivariate Cox analysis confirmed that only WPNI 3 could independently predict patients' prognosis, which could be explained by a more damaged immune response in WPNI 3 patients with less CD3⁺CD8⁺ T cells and CD19⁺ B cells. Conclusively, WPNI by trichotomy provide more meticulous and precise pathological information for tumor-nerve interactions in OSCC patients.

Differential Actions of Muscarinic Receptor Subtypes in Gastric, Pancreatic, and Colon Cancer

Cancers arising from gastrointestinal epithelial cells are common, aggressive, and difficult to treat. Progress in this area resulted from recognizing that the biological behavior of these cancers is highly dependent on bioactive molecules released by neurocrine, paracrine, and autocrine mechanisms within the tumor microenvironment. For many decades after its discovery as a neurotransmitter, acetylcholine was thought to be synthesized and released uniquely from neurons and considered the sole physiological ligand for muscarinic receptor subtypes, which were believed to have similar or redundant actions. In the intervening years, we learned this former dogma is not tenable. (1) Acetylcholine is not produced and released only by neurons. The cellular machinery required to synthesize and release acetylcholine is present in immune, cancer, and other cells, as well as in lower organisms (e.g., bacteria) that inhabit the gut. (2) Acetylcholine is not the sole physiological activator of muscarinic receptors. For example, selected bile acids can modulate muscarinic receptor function. (3) Muscarinic receptor subtypes anticipated to have overlapping functions based on similar G protein coupling and downstream signaling may have unexpectedly diverse actions. Here, we review the relevant research findings supporting these conclusions and discuss how the complexity of muscarinic receptor biology impacts health and disease, focusing on their role in the initiation and progression of gastric, pancreatic, and colon cancers.