Redefining Perineural Invasion: Integration of Biology With Clinical Outcome

Tumor innervation in cervical cancer: Prognostic insights from myelin-associated risk signatures

The reported frequencies of perineural invasion (PNI) in human cervical cancer, ranging from 7.0% to 35.1%, may underestimate the significant role that nerves play in cervical cancer progression. Neurosecretory factors can promote tumor migration and invasion, even in cases classified as "PNI-negative". This study aimed to clarify whether tumor innervation influences tumor progression and cervical cancer patient outcomes. We first evaluated the gene signatures of human myelinating Schwann cells (SCs) using the Inferring Pathway Activity and Suppression (IPAS) scoring system to predict the degree of tumor innervation in 304 cervical cancer patients from The Cancer Genome Atlas (TCGA) database. Subsequently, we constructed a myelin-associated risk prognostic signature using LASSO regression analysis. Finally, we obtained a risk score using a quantitative formula and categorized all samples into high- and low-risk score groups. Our results indicated that tumor innervation in cervical cancer is associated with poor patient survival. Higher levels of innervation were correlated with an impaired immune response and reduced expression of immune checkpoints, including PD-L1. The prognostic model demonstrated excellent consistency between predicted and actual survival outcomes. Overall, tumor innervation plays a crucial role in regulating cervical cancer prognosis. The identified prognostic risk signatures offer a valuable tool for risk stratification and prognostic prediction in clinical practice.

Cancer neuroscience in head and neck: interactions, modulation, and therapeutic strategies

Head and neck cancer (HNC) is an aggressive malignancy with significant effects on the innervation. Not only is it at the top of the cancer spectrum with a dismal prognosis, but it also imposes considerable stress on patients and society owing to frequent neurological symptoms. With progress in cancer neuroscience, the interactions between HNC and the nervous system, as well as the underlying mechanisms, have become increasingly clear. Compelling evidence suggests communication of information between cancer and nerve cells and devastation of the neurological system with tumor growth. However, the thorough grasp of HNC in cancer neuroscience has been severely constrained by the intricacy of HNC and fragmented research. This review comprehensively organizes and summarizes the latest research on the crosstalk between HNC and the nervous system. It aims to clarify various aspects of the neurological system in HNC, including the physiology, progression, and treatment of cancer. Furthermore, the opportunities and challenges of cancer neuroscience in HNC are discussed, which offers fresh perspectives on the neurological aspects of HNC diagnosis and management.

Perineural spread evaluation of cranial nerves in nasopharyngeal carcinoma: superiority and reliability of isovolumetric MR imaging

Purpose

The purpose of this study was to investigate the advantage of three-dimensional liver acquisition with volume acceleration-flexible (3D LAVA_Flex) for perineural spread (PNS) status of nasopharyngeal carcinoma (NPC) in comparison with two-dimensional magnetic resonance sequences.

Materials and methods

Sixty pathological proved NPC patients were prospective enrolled. A protocol included T2-weighted imaging with fat suppression (T2WI fs), T1-weighted imaging (T1WI) without and with contrast enhancement (T1WI ce), and 3D LAVA_Flex was applied for the recruited subject. After determining radiologic diagnostic criteria, the PNS status of cranial nerves (CNs) was carefully interpreted and recorded at the nerve level, anterior and posterior subgroup level, and individual level, respectively. Chi-square test [or McNemar-Bowker (MB) test], Fisher test, and intraclass correlation analysis were used. A P < 0.05 indicated statistical significance.

Results

PNS rates of the CNs in the advanced T3 to T4 stage subgroup were significantly different in evaluations performed with 3D LAVA_Flex, T2WI fs, T1WI, and T1WI ce at the patient level (n = 51, MB test, all P ≤ 0.031) and posterior CN level (MB test, all P ≤ 0.016). At the nerve level, 3D LAVA_Flex showed greater PNS detectability than T2WI fs, T1WI, and T1WI ce for CN V3 division (P = 0.031, 0.016, and 0.016, respectively), hypoglossal nerve (P = 0.002, 0.016, and 0.008, respectively), and external posterior CN IX-XII in carotid space (all P = 0.001), and T2WI fs and T1WI for CN IX-XI (P = 0.031, 0.001).

Conclusions

3D LAVA_Flex could improve both accuracy and reliability of PNS evaluation of CNs in the advanced NPC cohort and may facilitate decision making for therapeutic strategies.

Neuroscience in peripheral cancers: tumors hijacking nerves and neuroimmune crosstalk

Cancer neuroscience is an emerging field that investigates the intricate relationship between the nervous system and cancer, gaining increasing recognition for its importance. The central nervous system governs the development of the nervous system and directly affects brain tumors, and the peripheral nervous system (PNS) shapes the tumor microenvironment (TME) of peripheral tumors. Both systems are crucial in cancer initiation and progression, with recent studies revealing a more intricate role of the PNS within the TME. Tumors not only invade nerves but also persuade them through remodeling to further promote malignancy, creating a bidirectional interaction between nerves and cancers. Notably, immune cells also contribute to this communication, forming a triangular relationship that influences protumor inflammation and the effectiveness of immunotherapy. This review delves into the intricate mechanisms connecting the PNS and tumors, focusing on how various immune cell types influence nerve‒tumor interactions, emphasizing the clinical relevance of nerve‒tumor and nerve‒immune dynamics. By deepening our understanding of the interplay between nerves, cancer, and immune cells, this review has the potential to reshape tumor biology insights, inspire innovative therapies, and improve clinical outcomes for cancer patients.

Risk Factors and Prognostic Factors in GBC

Background: Gallbladder cancer (GBC) is a rare entity with a poor prognosis, usually discovered late due to nonspecific symptoms; therefore, over the last years, attention has been focused on identifying the risk factors for developing this malignancy in order to provide an early diagnosis, as well as new prognostic factors in order to modulate the long-term evolution of such cases. The aim of this review is to discuss both major risk factors and prognostic factors in GBC for a better understanding and integration of relevant and currently available information. Methods: A literature search was performed using Cochrane Library, PubMed, Google Scholar, Elsevier, and Web of Science; studies published after the year of 2000, in English, were reviewed. Results: Over time, risk factors associated with the development of GBC have been identified, which outline the profile of patients with this disease. The most important prognostic factors in GBC remain TNM staging, safety margin, and R0 status, along with perineural invasion and lymphovascular invasion. Both the technique and experience of the surgeons and a pathological examination that ensures final staging are particularly important and increase the chances of survival of the patients. Conclusions: improvements in surgical techniques and pathological analyses might provide better and more consistent guidance for medical staff in the management of patients with GBC.

Neuroimmune cell interactions and chronic infections in oral cancers

Inflammation is a process that is associated with the activation of distal immunosuppressive pathways that have evolved to restore homeostasis and prevent excessive tissue destruction. However, long-term immunosuppression resulting from systemic and local inflammation that may stem from dysbiosis, infections, or aging poses a higher risk for cancers. Cancer incidence and progression dramatically increase with chronic infections including HIV infection. Thus, studies on pro-tumorigenic effects of microbial stimulants from resident microbiota and infections in the context of inflammation are needed and underway. Here, we discuss chronic infections and potential neuro-immune interactions that could establish immunomodulatory programs permissive for tumor growth and progression.

Placental growth factor promotes neural invasion and predicts disease prognosis in resectable pancreatic cancer

BACKGROUND

Surgery represents the only curative treatment option for pancreatic ductal adenocarcinoma (PDAC), but recurrence in more than 85% of patients limits the success of curative-intent tumor resection. Neural invasion (NI), particularly the spread of tumor cells along nerves into extratumoral regions of the pancreas, constitutes a well-recognized risk factor for recurrence. Hence, monitoring and therapeutic targeting of NI offer the potential to stratify recurrence risk and improve recurrence-free survival. Based on the evolutionary conserved dual function of axon and vessel guidance molecules, we hypothesize that the proangiogenic vessel guidance factor placental growth factor (PlGF) fosters NI. To test this hypothesis, we correlated PlGF with NI in PDAC patient samples and functionally assessed its role for the interaction of tumor cells with nerves.

METHODS

Serum levels of PlGF and its soluble receptor sFlt1, and expression of PlGF mRNA transcripts in tumor tissues were determined by ELISA or qPCR in a retrospective discovery and a prospective validation cohort. Free circulating PlGF was calculated from the ratio PlGF/sFlt1. Incidence and extent of NI were quantified based on histomorphometric measurements and separately assessed for intratumoral and extratumoral nerves. PlGF function on reciprocal chemoattraction and directed neurite outgrowth was evaluated in co-cultures of PDAC cells with primary dorsal-root-ganglia neurons or Schwann cells using blocking anti-PlGF antibodies.

RESULTS

Elevated circulating levels of free PlGF correlated with NI and shorter overall survival in patients with PDAC qualifying for curative-intent surgery. Furthermore, high tissue PlGF mRNA transcript levels in patients undergoing curative-intent surgery correlated with a higher incidence and greater extent of NI spreading to tumor-distant extratumoral nerves. In turn, more abundant extratumoral NI predicted shorter disease-free and overall survival. Experimentally, PlGF facilitated directional and dynamic changes in neurite outgrowth of primary dorsal-root-ganglia neurons upon exposure to PDAC derived guidance and growth factors and supported mutual chemoattraction of tumor cells with neurons and Schwann cells.

CONCLUSION

Our translational results highlight PlGF as an axon guidance factor, which fosters neurite outgrowth and attracts tumor cells towards nerves. Hence, PlGF represents a promising circulating biomarker of NI and potential therapeutic target to improve the clinical outcome for patients with resectable PDAC.

Impact of Adjuvant Radiotherapy in Squamous Cell Carcinoma of the Oral Cavity with Perineural Invasion

OBJECTIVE

Current guidelines indicate postoperative radiotherapy (PORT) in oral squamous cell carcinoma (OSCC) with perineural invasion (PNI), however, its real benefit has never been proven. The aim of our study is to investigate the benefit of PORT in OSCC patients with PNI in terms of survival and disease control.

DATA SOURCES

The Pubmed/MEDLINE, Cochrane Library, and Scopus databases.

REVIEW METHODS

Patients with PNI + OSCC treated with primary surgery were extracted from the included studies. The pooled logHR was calculated by comparing patients who underwent PORT to those who underwent only observation for overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and locoregional control (LRC).

RESULTS

About 690 patients with primary OSCC and PNI were included from nine studies. 374 (54.2%) patients underwent PORT, while 316 (45.8%) underwent observation. Analyses showed non-significant difference between the two groups for OS (HR: 1.01; 95% CI: 0.38-2.69), DSS (HR: 2.03; 95% CI: 0.54-7.56), and LRC (HR: 0.89; 95% CI: 0.53-1.50). They showed a significant difference in terms of DFS (HR: 0.86; 95% CI: 0.77-0.97).

CONCLUSION

The real benefit of PORT in OSCC patients with PNI is still unclear, although it may have a positive impact on DFS. Clinicians should consider individual patient's characteristics, tumor factors, and treatment goals when deciding whether to recommend PORT. Further studies are needed to clarify which entity of PNI really benefits from PORT.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:2019-2027, 2024.

From pain to tumor immunity: influence of peripheral sensory neurons in cancer

The nervous and immune systems are the primary sensory interfaces of the body, allowing it to recognize, process, and respond to various stimuli from both the external and internal environment. These systems work in concert through various mechanisms of neuro-immune crosstalk to detect threats, provide defense against pathogens, and maintain or restore homeostasis, but can also contribute to the development of diseases. Among peripheral sensory neurons (PSNs), nociceptive PSNs are of particular interest. They possess a remarkable capability to detect noxious stimuli in the periphery and transmit this information to the brain, resulting in the perception of pain and the activation of adaptive responses. Pain is an early symptom of cancer, often leading to its diagnosis, but it is also a major source of distress for patients as the disease progresses. In this review, we aim to provide an overview of the mechanisms within tumors that are likely to induce cancer pain, exploring a range of factors from etiological elements to cellular and molecular mediators. In addition to transmitting sensory information to the central nervous system, PSNs are also capable, when activated, to produce and release neuropeptides (e.g., CGRP and SP) from their peripheral terminals. These neuropeptides have been shown to modulate immunity in cases of inflammation, infection, and cancer. PSNs, often found within solid tumors, are likely to play a significant role in the tumor microenvironment, potentially influencing both tumor growth and anti-tumor immune responses. In this review, we discuss the current state of knowledge about the degree of sensory innervation in tumors. We also seek to understand whether and how PSNs may influence the tumor growth and associated anti-tumor immunity in different mouse models of cancer. Finally, we discuss the extent to which the tumor is able to influence the development and functions of the PSNs that innervate it.

Measurement of the Association of Pain with Clinical Characteristics in Oral Cancer Patients at Diagnosis and Prior to Cancer Treatment

Aim

Oral cancer patients suffer pain at the site of the cancer, which degrades quality of life (QoL). The University of California San Francisco Oral Cancer Pain Questionnaire (UCSFOCPQ), the only validated instrument specifically designed for measuring oral cancer pain, measures the intensity and nature of pain and the level of functional restriction due to pain.

Purpose

The aim of this study was to compare pain reported by untreated oral cancer patients on the UCSFOCPQ with pain they reported on the Brief Pain Inventory (BPI), an instrument widely used to evaluate cancer and non-cancer pain.

Patients and Methods

The correlation between pain measured by the two instruments and clinical characteristics were analyzed. Thirty newly diagnosed oral cancer patients completed the UCSFOCPQ and the BPI.

Results

Pain severity measurements made by the UCSFOCPQ and BPI were concordant; however, the widely used BPI average pain over 24 hours score appeared less sensitive to detect association of oral cancer pain with clinical characteristics of patients prior to treatment (nodal status, depth of invasion, DOI). A BPI average score that includes responses to questions that measure both pain severity and interference with function performs similarly to the UCSFOCPQ in detection of associations with nodal status, pathologic T stage (pT stage), stage and depth of invasion (DOI).

Conclusion

Pain assessment instruments that measure sensory and interference dimensions of oral cancer pain correlate with biologic features and clinical behavior.

Tumor Neurobiology in the Pathogenesis and Therapy of Head and Neck Cancer

The neurobiology of tumors has attracted considerable interest from clinicians and scientists and has become a multidisciplinary area of research. Neural components not only interact with tumor cells but also influence other elements within the TME, such as immune cells and vascular components, forming a polygonal relationship to synergistically facilitate tumor growth and progression. This review comprehensively summarizes the current state of the knowledge on nerve-tumor crosstalk in head and neck cancer and discusses the potential underlying mechanisms. Several mechanisms facilitating nerve-tumor crosstalk are covered, such as perineural invasion, axonogenesis, neurogenesis, neural reprogramming, and transdifferentiation, and the reciprocal interactions between the nervous and immune systems in the TME are also discussed in this review. Further understanding of the nerve-tumor crosstalk in the TME of head and neck cancer may provide new nerve-targeted treatment options and help improve clinical outcomes for patients.

Immunohistochemical Expression of Epithelial Cell Adhesion Molecule (EpCAM) in Salivary Gland Cancer: Correlation with the Biological Behavior

Salivary gland neoplasms comprise a diverse group of tumors with different biological behaviors and clinical outcomes. Understanding the underlying molecular alterations associated with these malignancies is critical for accurate diagnosis, prognosis, and treatment strategies. Among the many biomarkers under investigation, epithelial cell adhesion molecule (EpCAM) has emerged as a promising candidate in salivary gland cancer research. This article aims to provide a comprehensive overview of the differential expression of EpCAM in salivary gland cancer and its potential correlation with the biological behavior of these tumors. The clinical characteristics of 65 patients with salivary gland malignancy of different histopathological subtypes were included. We report the differential expression of EpCAM and the relationship between the clinical and histopathologic features of these tumors. Regarding the evaluation of the effect of EpCAM expression on survival, in our study, we showed that tumors with high EpCAM expression had reduced disease-free survival (DFS) and overall survival (OS) (p < 0.001) compared to patients with cancers with low EpCAM expression. In addition, the concurrent presence of perineural invasion and positive EpCAM expression appeared to be associated with shorter disease-free survival and overall survival. In conclusion, our study confirmed the prognostic value of detecting perineural invasion and EpCAM expression.

Increased Nerve Density Adversely Affects Outcome in Oral Cancer

PURPOSE

Perineural invasion (PNI) in oral cavity squamous cell carcinoma (OSCC) is associated with poor survival. Because of the risk of recurrence, patients with PNI receive additional therapies after surgical resection. Mechanistic studies have shown that nerves in the tumor microenvironment promote aggressive tumor growth. Therefore, in this study, we evaluated whether nerve density (ND) influences tumor growth and patient survival. Moreover, we assessed the reliability of artificial intelligence (AI) in evaluating ND.

EXPERIMENTAL DESIGN

To investigate whether increased ND in OSCC influences patient outcome, we performed survival analyses. Tissue sections of OSCC from 142 patients were stained with hematoxylin and eosin and IHC stains to detect nerves and tumor. ND within the tumor bulk and in the adjacent 2 mm was quantified; normalized ND (NND; bulk ND/adjacent ND) was calculated. The impact of ND on tumor growth was evaluated in chick chorioallantoic-dorsal root ganglia (CAM-DRG) and murine surgical denervation models. Cancer cells were grafted and tumor size quantified. Automated nerve detection, applying the Halo AI platform, was compared with manual assessment.

RESULTS

Disease-specific survival decreased with higher intratumoral ND and NND in tongue SCC. Moreover, NND was associated with worst pattern-of-invasion and PNI. Increasing the number of DRG, in the CAM-DRG model, increased tumor size. Reduction of ND by denervation in a murine model decreased tumor growth. Automated and manual detection of nerves showed high concordance, with an F1 score of 0.977.

CONCLUSIONS

High ND enhances tumor growth, and NND is an important prognostic factor that could influence treatment selection for aggressive OSCC. See related commentary by Hondermarck and Jiang, p. 2342.

Basal Cell Carcinoma Perineural Invasion and Suggestive Signs of Perineural Invasion-Findings and Perspectives

Basal cell carcinoma (BCC) is a malignant tumor with a rising incidence and is the beneficiary of several innovative evaluation techniques. Histopathology remains the gold standard for assessment, having the possibility of addressing multiple high-risk factors such as perineural invasion (PNI). The current study included a number of 244 BCC patients and targeted the identification of positive PNI and its suggestive signs, and whether they correlated or not with other high-risk tumor signs. PNI was found in 20.1% of patients, with 30.7% of patients having perineural chronic inflammation (PCI), which is a suggestive sign of PNI. PNI was also found in larger tumors, with deeper Clark levels, in high-risk BCCs and high-grade tumors. PNI and PCI are both important for pathology reporting, aiding in treatment choice and further patient management, with possibly positive outcomes concerning morbidity and mortality.

The 3D's of Neural Phenotypes in Oral Cancer: Distance, Diameter, and Density

Squamous cell carcinoma of the oral cavity (OSCC) is the most common type of head and neck cancer; survival is poor, and response to treatment varies. Metastasis or recurrence in the regional lymph nodes is associated with poor survival. Consequently, overt or occult spread to the lymph nodes is used to identify patients who will receive adjuvant radiation therapy. Perineural invasion and the diameter of nerves exhibiting perineural invasion have also been suggested to be of prognostic significance. The explosion of interest in cancer neuroscience in the last two decades has led to novel biological insights into interactions between nerves and tumor cells. However, the criteria for defining perineural invasion have lagged behind current knowledge. It is important to re-evaluate the concept of perineural invasion and identify other neural phenotypes in OSCC that can impact treatment selection and prognosis. In addition to perineural invasion, neural phenotypes that are of potential relevance to tumor progression include nerve-tumor distance, nerve diameter, and nerve density. This manuscript discusses the translational significance of recent mechanistic studies on the progression of oral cancer.

YAP1-TEAD1 mediates the perineural invasion of prostate cancer cells induced by cancer-associated fibroblasts

Perineural invasion (PNI) driven by the tumor microenvironment (TME) has emerged as a key pattern of metastasis of prostate cancer (PCa), while its underlying mechanism is still elusive. Here, we identified increased CAFs and YAP1 expression levels in patients with metastatic PCa. In the cultured PCa cell line LNCaP, co-culture with cancer-associated fibroblasts (CAFs) could upregulate YAP1 protein expression. Either ectopic overexpression of YAP1 or co-culture with CAFs could promote the infiltration of LNCaPs towards dorsal root ganglia (DRG). This effect could be blocked using an YAP1 inhibitor. In vivo, overexpression of YAP1 could increase PNI in a mouse model of sciatic nerve tumor invasion. Mechanistically, TEAD1 binds to the NGF promotor and YAP1/TEAD1 activates its transcription and consequently increases NGF secretion. In turn, PCa cells treated with CM from CAFs or stable YAP1 overexpression can stimulate DRG to secrete CCL2. The epithelial-to-mesenchymal transition (EMT) of PCa cells is thus activated via CCL2/CCR2. Overall, our data demonstrate that CAFs can activate YAP1/TEAD1 signaling and increase the secretion of NGF, therefore promoting PCa PNI. In addition, EMT induced by PNI suggests a feedback loop is present between neurons and PCa cells.

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.

Spatial and Transcriptomic Analysis of Perineural Invasion in Oral Cancer

PURPOSE

Perineural invasion (PNI), a common occurrence in oral squamous cell carcinomas, is associated with poor survival. Consequently, these tumors are treated aggressively. However, diagnostic criteria of PNI vary and its role as an independent predictor of prognosis has not been established. To address these knowledge gaps, we investigated spatial and transcriptomic profiles of PNI-positive and PNI-negative nerves.

EXPERIMENTAL DESIGN

Tissue sections from 142 patients were stained with S100 and cytokeratin antibodies. Nerves were identified in two distinct areas: tumor bulk and margin. Nerve diameter and nerve-to-tumor distance were assessed; survival analyses were performed. Spatial transcriptomic analysis of nerves at varying distances from tumor was performed with NanoString GeoMx Digital Spatial Profiler Transcriptomic Atlas.

RESULTS

PNI is an independent predictor of poor prognosis among patients with metastasis-free lymph nodes. Patients with close nerve-tumor distance have poor outcomes even if diagnosed as PNI negative using current criteria. Patients with large nerve(s) in the tumor bulk survive poorly, suggesting that even PNI-negative nerves facilitate tumor progression. Diagnostic criteria were supported by spatial transcriptomic analyses of >18,000 genes; nerves in proximity to cancer exhibit stress and growth response changes that diminish with increasing nerve-tumor distance. These findings were validated in vitro and in human tissue.

CONCLUSIONS

This is the first study in human cancer with high-throughput gene expression analysis in nerves with striking correlations between transcriptomic profile and clinical outcomes. Our work illuminates nerve-cancer interactions suggesting that cancer-induced injury modulates neuritogenesis, and supports reclassification of PNI based on nerve-tumor distance rather than current subjective criteria.

Efficient Perineural Invasion Detection of Histopathological Images Using U-Net

Perineural invasion (PNI), a sign of poor diagnosis and tumor metastasis, is common in a variety of malignant tumors. The infiltrating patterns and morphologies of tumors vary by organ and histological diversity, making PNI detection difficult in biopsy, which must be performed manually by pathologists. As the diameters of PNI nerves are measured on a millimeter scale, the PNI region is extremely small compared to the whole pathological image. In this study, an efficient deep learning-based method is proposed for detecting PNI regions in multiple types of cancers using only PNI annotations without detailed segmentation maps for each nerve and tumor cells obtained by pathologists. The key idea of the proposed method is to train the adopted deep learning model, U-Net, to capture the boundary regions where two features coexist. A boundary dilation method and a loss combination technique are proposed to improve the detection performance of PNI without requiring full segmentation maps. Experiments were conducted with various combinations of boundary dilation widths and loss functions. It is confirmed that the proposed method effectively improves PNI detection performance from 0.188 to 0.275. Additional experiments were also performed on normal nerve detection to validate the applicability of the proposed method to the general boundary detection tasks. The experimental results demonstrate that the proposed method is also effective for general tasks, and it improved nerve detection performance from 0.511 to 0.693.

Galanin mediates tumor-induced immunosuppression in head and neck squamous cell carcinoma

Purpose

Galanin receptor 2 (GALR2) plays a significant role in the progression of head and neck squamous cell carcinomas (HNSCC). Since there is virtually no information on immunomodulation mediated by its ligand in the tumor microenvironment, we assessed the effects of galanin on peripheral blood mononuclear cells (PBMCs).

Methods

After verification of GALR2 expression and it activity in PBMCs we evaluated the effect of galanin and conditioned media from HNSCC cell lines silenced for galanin or antibody-depleted, on proliferation, apoptosis, cytokine expression and activation/differentiation of immune cells.

Results

We found that galanin alone and as a component of the HNSCC secretome decreased HNSCC cell proliferation and expression of pro-inflammatory cytokines (IFNγ, IL-12, IL-17A, IL-1α, IL-6 and TNF-α), whilst increasing apoptosis and expression of pro-tumoral cytokines/growth factors (IL-10, IL-4, PDGF and GM-CSF). T cell activation (using CD69 as activation marker) and anti-tumoral phenotypes in CD4⁺ T cells (Th1 and Th17) were found to be suppressed. In vivo, tumor growth was found to be increased in the presence of galanin-stimulated PBMCs. Data from The Cancer Genome Atlas (TCGA) revealed that high expression of galanin was associated with a reduced overall survival of patients with HNSCC.

Conclusion

Our data indicate that galanin secreted by HNSCC cells exhibits immune-suppressive and pro-tumoral effects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-021-00631-y.

Cross Talk Between Macrophages and Cancer Cells in the Bone Metastatic Environment

The skeleton is a common site for cancer metastases with the bone microenvironment providing the appropriate conditions for cancer cell colonization. Once in bone, cancer cells effectively manipulate their microenvironment to support their growth and survival. Despite previous efforts to improve treatment modalities, skeletal metastases remain with poor prognoses. This warrants an improved understanding of the mechanisms leading to bone metastasis that will aid development of effective treatments. Macrophages in the tumor microenvironment are termed tumor associated macrophages (TAMs) and their crosstalk with cancer cells is critical in regulating tumorigenicity in multiple cancers. In bone metastases, this crosstalk is also being increasingly implicated but the specific signaling pathways remain incompletely understood. Here, we summarize the reported functions, interactions, and signaling of macrophages with cancer cells during the metastatic cascade to bone. Specifically, we review and discuss how these specific interactions impact macrophages and their profiles to promote tumor development. We also discuss the potential of targeting this crosstalk to inhibit disease progression. Finally, we identify the remaining knowledge gaps that will need to be addressed in order to fully consider therapeutic targeting to improve clinical outcomes in cancer patients.

Nerve density in cancer: Less is better

The density of nerves in cancer is emerging as a relevant clinical parameter for patient survival. Nerves in the tumor microenvironment have been associated with poor survival and recurrence, particularly if involved in perineural invasion. However, usually only a few nerves inside a tumor are affected by perineural invasion, while most nerves are not. Mechanistic studies have shown nerve-secreted factors promote tumor growth and invasion thereby making tumors more aggressive. Therefore, the overall number of nerves in the tumor microenvironment should be more representative of the nerve-tumor biological interaction than perineural invasion. This review summarizes the available clinical information about nerve density as a measure of clinical outcome in cancer and explores the mechanisms underlying nerve density in cancer, specifically, neurogenesis, axonogenesis, and neurotropism.

Review of Perineural Invasion in Keratinocyte Carcinomas

Perineural invasion is an infiltrative process of peripheral nerves by the primary neoplasm within the immediate vicinity. Aggressive forms of keratinocyte carcinomas, such as basal cell and squamous cell carcinomas, may feature perineural invasion, which is often associated with tumor recurrence and poorer prognosis. Diagnosis requires a high clinical suspicion. Imaging and histopathology are used to assess for extent of disease while surgical excision with complete circumferential peripheral and margin assessment is the treatment goal. However, there is still significant uncertainty about adjuvant chemotherapy and definitive management guidelines. Here, we summarize the current understanding of this complex pathogenic process, the clinical presentation, and the significance of perineural inflammation. We also discuss the recommendations about staging, prognosis, adjuvant radiotherapy, and general guidelines for managing keratinocyte carcinomas with perineural invasion. A better understanding of perineural invasion is essential to improve diagnosis, tailor interventions, and mitigate patient morbidity and mortality.

Interobserver Variation in Evaluating Perineural Invasion for Oral Squamous Cell Carcinoma: Phase 2 Survey Study

In a previous study, we found interobserver agreement among 88 board-certified pathologists evaluating perineural invasion (PNI) in oral squamous cell carcinoma (OSCC) was fair, and participants most often used the following criteria: (1) tumor invading the perineurium, (2) tumor surrounding a nerve. In this study, we aimed to determine whether application of these most commonly used criteria may improve interobserver agreement. 512 pathologists were invited to participate in a web-based survey. Participants were asked to assess the presence/absence of PNI in a set of OSCC photomicrographs by applying each of the two criteria above. The survey was completed by 84 board-certified pathologists [mean age: 52 years (range 31-81), mean years in practice: 19 (range 1-56)]. Interobserver agreement was moderate (k = 0.46, 95% CI 0.45-0.46) when using definition #1 (tumor invading the perineurium) and fair (k = 0.24, 95% CI 0.23-0.25) when using definition #2 (tumor surrounding a nerve). By comparison, interobserver agreement was fair (k = 0.36, 95% CI 0.35-0.37) among phase 1 participants asked to evaluate these photomicrographs as they would in their pathology practice. Differences in kappa between definition #1 and phase 1, definition #2 and phase 2, and definition #1 and #2 were statistically significant (p < 0.001). Compared to our prior study based on pathologists' personal views, the current study shows improved interobserver agreement with application of the criterion, "tumor invading the perineurium." However, further work is needed to delineate concise, objective, and more reproducible criteria for histopathologic assessment of PNI.

Prognostic value of lymphovascular and perineural invasion in squamous cell carcinoma of the tongue

OBJECTIVE

The objective of this study was to investigate the association between survival rate and lymphovascular invasion (LVI) and perineural invasion (PNI) in the tumor invasive front (TIF) of squamous cell carcinoma of the tongue (TSCC).

STUDY DESIGN

Seventy patients with TSCC were included. The retrospective analysis included demographic, clinical, and histopathologic data. Tissue blocks containing the TIF were stained with anti-α-smooth muscle actin and anti-S100 to detect LVI and PNI, respectively. Overall survival (OS) and disease-specific survival (DSS) were assessed using Pearson's chi-square test, Kaplan-Meier method, and Cox regression.

RESULTS

LVI and PNI were detected in 61.4% and 78.6% of the TSCC samples at the TIF, respectively. LVI and PNI were present in 54.3% of the cases and were associated with advanced clinical stage, lymph node resection, metastatic nodes, and lower survival (P < .05). The 5-year OS and DSS rates were 44% and 52%, respectively. Multivariate analysis showed that primary tumors >3.0 cm (hazard ratio = 4.29; P = .004) and a concomitant presence of LVI and PNI at the TIF (hazard ratio = 4.0; P = .012) were independent predictors for worse DSS.

CONCLUSION

LVI and PNI, identified by immunostaining at the TIF, are potential prognostic markers of TSCC.

The Diagnosis of Perineural Invasion: A Crucial Factor in Novel Algorithm of Coexistence of Conventional and Nerve-Sparing Radical Hysterectomy

Nerve-sparing radical hysterectomy (NSRH) was introduced to mitigate adverse effects associated with conventional radical hysterectomy (CRH) in cervical cancer. However, the introduction of NSRH was compromised by possible existence of perineural invasion (PNI). Additionally, the coexistence of NSRH and CRH is currently the fact. The aim of the study was to review the literature and attempt to construct a novel and preliminary PNI diagnostic algorithm that would establish the coexistence of NSRH and CRH in one system of early-stage cervical cancer (ESCC) surgical treatment. This algorithm takes into account the PNI risk factors and current and future diagnostic methods such as imaging and biopsy.

Squamous cell carcinoma subverts adjacent histologically normal epithelium to promote lateral invasion

Recurrent and new tumors, attributed in part to lateral invasion, are frequent in squamous cell carcinomas and lead to poor survival. We identified a mechanism by which cancer subverts adjacent histologically normal epithelium to enable small clusters of cancer cells to burrow undetected under adjacent histologically normal epithelium. We show that suppression of DMBT1 within cancer promotes aggressive invasion and metastasis in vivo and is associated with metastasis in patients. Cancer cells via TGFβ1 and TNFα also suppress DMBT1 in adjacent histologically normal epithelium, thereby subverting it to promote invasion of a small population of tumor cells. The sufficiency of DMBT1 in this process is demonstrated by significantly higher satellite tumor nests in Dmbt1-/- compared with wild-type mice. Moreover, in patients, invasion of small tumor nests under adjacent histologically normal epithelium is associated with increased risk for recurrence and shorter disease-free survival. This study demonstrates a crucial role of adjacent histologically normal epithelium in invasion and its important role in the tumor microenvironment and opens new possibilities for therapeutic strategies that reduce tumor recurrence.

Clinical and pathological risk factors for worse stage and mortality of eyelid and periocular squamous cell carcinoma

BACKGROUND

The clinical and pathological risk factors for worse T stage and prognosis in eyelid and periocular squamous cell carcinomas (SCCs) remain unclear. P63 was reported to predict a worse prognosis in other SCCs; however, this correlation was not validated in eyelid and periocular SCCs.

METHODS

We reported on a retrospective case series of 85 consecutive patients with eyelid and periocular SCCs from 1995 to 2019. Cox proportional hazards regression models and logistic regression models were applied for risk factor analysis.

RESULTS

Thirty-nine (45.8%) patients were diagnosed with T4 SCCs. Four (5.1%) patients developed nodal metastasis, and five (6.4%) patients developed distant metastasis during the follow-up. 2-year and 5-year disease-specific survival rates were 95.3% and 86.4%, respectively. Poorly or moderately differentiated eyelid and periocular SCCs were associated with worse T stage (p=0.001; p=0.008). Poor differentiation was associated with a higher risk of recurrence (p=0.024). Disease-specific death was more common in patients with T4 stage SCCs (p=0.038, HR=9.05). P63 expression was more common in patients with T3c or worse stage (p=0.008, OR=3.77). P63 expression alone was associated with worse differentiation (p=0.029), higher risk of perineural invasion (p=0.042, OR=4.61) and metastasis (p=0.009, HR=3.99). P63 expression (p=0.012, HR=7.80), coexpression of P63 and Ki67 (p=0.007, HR=9.21) and distant metastasis (p=0.001, HR=11.23) were associated with disease-specific death.

CONCLUSION

Patients presented with more aggressive orbital invasion features and a higher rate of distant metastasis in this cohort. P63 and coexpression of Ki67 predicted a worse stage, differentiation and prognosis, including metastasis and death due to disease.

Contribution of Genomics to the Surgical Management and Study of Oral Cancer

Background

Oral squamous cell carcinoma (OSCC) is the most frequent type of tumor arising from the oral cavity. Surgery is the cornerstone of the treatment of these cancers. Tumor biology has long been overlooked as an important contributor to the outcome of surgical procedures, but recent studies are challenging this concept. Molecular analyses of tumor DNA or RNA provide a rich source of information about the biology of OSCC.

Methods

We searched for relevant articles using PubMed. We examined in particular the prospect of applying molecular methods for minimally invasive exploration of OSCC biology.

Results

We examined five potential applications of genomics to the surgical management and study of OSCC: i) assessing oral potentially malignant lesions; ii) tumor staging prior to surgery; iii) predicting postoperative risk in locally advanced tumors; iv) measuring minimal residual disease and optimizing the longitudinal monitoring of OSCC; and v) predicting the efficacy of medical treatment.

Conclusions

Genomic information can be harnessed in order to identify new biomarkers that could improve the staging, choice of therapy and management of OSCC. The identification of new biomarkers is awaited for better personalization of the surgical treatment of OSCC.

Perineural invasion in head and neck squamous cell carcinoma: background, mechanisms, and prognostic implications

PURPOSE OF REVIEW

Perineural invasion (PNI) is a pathological feature frequently observed in head and neck squamous cell carcinoma (HNSCC). The difficulties of pathological standardization and the lack of a simple validated experimental model to study PNI render its analysis complex. Here, we aim to summarize the recent advances in the understanding of the biology of PNI in HNSCC and their potential clinical implications.

RECENT FINDINGS

PNI is a multistep process leading to a dialogue between cancer cells and nerve fibers in HNSCC. Recent studies have identified some of the active molecular mechanisms involved in PNI. Comprehensive studies addressing the transcriptional regulation of PNI bring interesting perspectives for a standardized molecular diagnosis of PNI and a better assessment of its contribution to the aggressiveness of HNSCC.

SUMMARY

Perineural invasion is a complex process that reflects specific tumor biology. In addition to unveiling new fundamental concepts about the tumor microenvironment, research on PNI promises to identify new biomarkers, enabling progress in therapeutic development against HNSCC.

The Histopathology of Oral Cancer Pain in a Mouse Model and a Human Cohort

Oral cancer patients often have severe, chronic, and mechanically induced pain at the site of the primary cancer. Oral cancer pain is initiated and maintained in the cancer microenvironment and attributed to release of mediators that sensitize primary sensory nerves. This study was designed to investigate the histopathology associated with painful oral cancers in a preclinical model. The relationship of pain scores with pathologic variables was also investigated in a cohort of 72 oral cancer patients. Wild-type mice were exposed to the carcinogen, 4-nitroquinoline 1-oxide (4NQO). Nociceptive (pain) behavior was measured with the dolognawmeter, an operant device and assay for measuring functional and mechanical allodynia. Lesions developed on the tongues and esophagi of the 4NQO-treated animals and included hyperkeratoses, papillomas, dysplasias, and cancers. Papillomas included lesions with benign and dysplastic pathological features. Two histologic subtypes of squamous cell carcinomas (SCCs) were identified-SCCs with exophytic and invasive components associated with papillary lesions (pSCCs) and invasive SCCs without exophytic histology (iSCCs). Only the pSCC subtype of tongue cancer was associated with nociceptive behavior. Increased tumor size was associated with greater nociceptive behavior in the mouse model and more pain experienced by oral cancer patients. In addition, depth of invasion was associated with patient-reported pain. The pSCC histology identifies 4NQO-induced tongue cancers that are expected to be enriched for expression and release of nociceptive mediators.

The biology and engineered modeling strategies of cancer-nerve crosstalk

A recent finding critical to cancer aggravation is the interaction between cancer cells and nerves. There exist two main modes of cancer-nerve interaction: perineural invasion (PNI) and tumor innervation. PNI occurs when cancer cells infiltrate the adjacent nerves, and its relative opposite, tumor innervation, occurs when axons extend into tumor bodies. Like most cancer studies, these crosstalk interactions have mostly been observed in patient samples and animal models at this point, making it difficult to understand the mechanisms in a controlled manner. As such, in recent years in vitro studies have emerged that have helped identify various microenvironmental factors responsible for cancer-nerve crosstalk, including but not limited to neurotrophic factors, neurotransmitters, chemokines, cancer-derived exosomes, and Schwann cells. The versatility of in vitro systems warrants continuous development to increase physiological relevance to study PNI and tumor innervation, for example by utilizing biomimetic three-dimensional (3D) culture systems. Despite the wealth of 3D in vitro cancer models, comparatively there exists a lack of 3D in vitro models of nerve, PNI, and tumor innervation. Native-like 3D in vitro models of cancer-nerve interactions may further help develop therapeutic strategies to curb nerve-mediated cancer aggravation. As such, we provide an overview of the key players of cancer-nerve crosstalk and current in vitro models of the crosstalk, as well as cancer and nerve models. We also discuss a few future directions in cancer-nerve crosstalk research.

Oral Cancer: Integration of Studies for Diagnostic and Therapeutic Precision

Head and neck cancers are among the 10 most common cancers in the world and include cancers of the oral cavity, hypopharynx, larynx, nasopharynx, and oropharynx. At least 90% of head and neck cancers are squamous cell carcinomas (SCCs). This summary discusses the integration of clinical and mechanistic studies in achieving diagnostic and therapeutic precision in the context of oral cancer. Specifically, based on recent mechanistic studies, a subsequent study reevaluated current diagnostic criteria of perineural invasion in patients with oral cavity SCC showing that overall survival could be associated with nerve-tumor distance; validation of the findings of this study from a small group of patients could lead to a personalized approach to treatment selection in patients with oral cavity SCC. Moreover, delineation of key pathways in SCC revealed novel treatment targets that can be exploited to develop personalized treatment strategies to achieve long-term remission.

Axon Guidance Molecules Promote Perineural Invasion and Metastasis of Orthotopic Pancreatic Tumors in Mice

BACKGROUND & AIMS

Little is known about mechanisms of perineural invasion (PNI) by pancreatic ductal adenocarcinomas (PDAs) or other tumors. Annexin A2 (ANXA2) regulates secretion of SEMA3D, an axon guidance molecule, which binds and activates the receptor PLXND1 to promote PDA invasion and metastasis. We investigated whether axon guidance molecules promote PNI and metastasis by PDA cells in mice.

METHODS

We performed studies in a dorsal root ganglion (DRG) invasion system, wild-type C57BL/6 mice (controls), mice with peripheral sensory neuron-specific disruption of PlxnD1 (PLAC mice), LSL-KRASG12D/+;LSL-TP53R172H/+;PDX-1-CRE+/+ (KPC) mice, and KPC mice crossed with ANXA2-knockout mice (KPCA mice). PDA cells were isolated from KPC mice and DRG cells were isolated from control mice. Levels of SEMA3D or ANXA2 were knocked down in PDA cells with small hairpin and interfering RNAs and cells were analyzed by immunoblots in migration assays, with DRGs and with or without antibodies against PLXND1. PDA cells were injected into the pancreas of control and PLAC mice, growth of tumors was assessed, and tumor samples were analyzed by histology. DRG cells were incubated with SEMA3D and analyzed by live imaging. We measured levels of SEMA3D and PLXND1 in PDA specimens from patients with PNI and calculated distances between tumor cells and nerves.

RESULTS

DRG cells increase the migration of PDC cells in invasion assays; knockdown of SEMA3D in PDA cells or antibody blockade of PLXND1 on DRG cells reduced this invasive activity. In mice, orthotopic tumors grown from PDA cells with knockdown of SEMA3D, and in PLAC mice, orthotopic tumors grown from PDA cells, had reduced innervation and formed fewer metastases than orthotopic tumors grown from PDA cells in control mice. Increased levels of SEMA3D and PLXND1 in human PDA specimens associated with PNI.

CONCLUSIONS

DRG cells increase the migratory and invasive activities of pancreatic cancer cells, via secretion of SEMA3D by pancreatic cells and activation of PLXND1 on DRGs. Knockdown of SEMA3D and loss of neural PLXND1 reduces innervation of orthotopic PDAs and metastasis in mice. Increased levels of SEMA3D and PLXND1 in human PDA specimens associated with PNI. Strategies to disrupt the axon guidance pathway mediated by SEMA3D and PLXND1 might be developed to slow progression of PDA.

The Chick Chorioallantoic Membrane In Vivo Model to Assess Perineural Invasion in Head and Neck Cancer

Perineural invasion is a phenotype in which cancer surrounds or invades the nerves. It is associated with poor clinical outcome for head and neck squamous cell carcinoma and other cancers. Mechanistic studies have shown that the molecular crosstalk between nerves and tumor cells occurs prior to physical interaction. There are only a few in vivo models to study perineural invasion, especially to investigate early progression, before physical nerve-tumor interactions occur. The chick chorioallantoic membrane model has been used to study cancer invasion, because the basement membrane of the chorionic epithelium mimics that of human epithelial tissue. Here we repurposed the chick chorioallantoic membrane model to investigate perineural invasion, grafting rat dorsal root ganglia and human head and neck squamous cell carcinoma cells onto the chorionic epithelium. We have demonstrated how this model can be useful to evaluate the ability of cancer cells to invade neural tissue in vivo.

Prognostic Score Predicts Survival in HPV-Negative Head and Neck Squamous Cell Cancer Patients

Although patients having head and neck squamous cell carcinoma (HNSCC) have high mortality, standardized prognostic tools are unavailable. As such, having a validated simple prognostic scoring system to help predict mortality in these high-risk patients is urgently needed. The current study aimed to develop and internally validate a prognostic scoring system for overall mortality in human papillomavirus (HPV)-independent HNSCC patients. Data on 400 consecutive patients from the Cancer Genome Atlas database with a known HPV-RNA negative status were analyzed. A prognostic model to predict patient overall mortality was developed using the logistic regression beta coefficients and a simple risk score was created. The model was internally validated using bootstrap validation with 2000 replications. Five covariates (age, pT, pN, perineural invasion, and EAp53 score) were used in the development of the mortality risk score in the final model. Three risk groups were stratified based on the prognostic scores: low-risk (<96 points), medium-risk (96-121 points), and high-risk (≥122 points) with a survival of 76%, 62% and 35%, respectively. The proposed model presented good discrimination in both the development (AUC = 0.76; 95% CI 0.70, 0.81) and bootstrap validation (AUC = 0.76; 95% CI 0.70, 0.81) with a non-significant Hosmer-Lemeshow chi-square of 6.17 (p = 0.63). The proposed prognostic scoring system is easy to use to predict patient overall mortality and could also help in the appropriate allocation of medical resources while managing HNSCC patients. External validation (including re-calibration if needed) should be conducted to test the model's generalizability in different populations.

Perineural invasion in cervical cancer: pay attention to the indications of nerve-sparing radical hysterectomy

Perineural invasion (PNI) in early-stage cervical cancer, is associated with multiple high-risk factors and represents a poor outcome in the patients. For nerve-sparing radical hysterectomy (NSRH) to become a standard and widely used treatment for cervical cancer, we need to define its oncological safety, and to establish standardized surgical procedures and indications of NSRH. Here, we review the definition and mechanisms, and clinical significance of PNI in cervical cancer, and discuss the indications of NSRH. PNI should be regarded as one of the main pathological features of cervical cancer and a factor affecting prognosis. A deeper understanding of PNI in cervical cancer, hopefully, will provide clear indications of NSRH.

Lactate Transporter Monocarboxylate Transporter 4 Induces Bone Pain in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) poses a significant challenge clinically, as it can invade facial bones and cause bone pain that is undertreated and poorly understood. Here we studied HNSCC bone pain (HNSCC-BP) in an intratibial mouse xenograft model that uses a human HNSCC cell line (SAS cells). These mice develop HNSCC-BP associated with an upregulation of phosphorylated ERK1/2 (pERK1/2), which is a molecular indicator of neuron excitation in the dorsal root ganglia (DRGs) of sensory nerve cell bodies. Our experiments demonstrated that the inhibition of monocarboxylate transporter 4 (MCT4) by short hairpin (shRNA) transduction suppressed the HNSCC-BP, the lactate level in bone marrow, and the pERK1/2 expression in DRG. The sensory nerves also expressed increased levels of the acid-sensing receptor TRPV1. DRG neurons co-cultured with SAS cells showed increased neurite outgrowth, and were inhibited by MCT4 silencing with shRNA. Collectively, our results show that HNSCC induced an acidic bone microenvironment that evokes HNSCC-BP via MCT4 expression.