Perineural Invasion in Head and Neck Cancer

Influence of Lymphangio vascular (V) and perineural (N) invasion on survival of patients with resected esophageal squamous cell carcinoma (ESCC): a single-center retrospective study

Background

Lymphangio vascular invasion (LVI) and perineural invasion (PNI) are associated with survival following resection for gastrointestinal cancer. But the relationship between LVI/PNI and survival of esophageal squamous cell carcinoma (ESCC) is still unclear. We aim to demonstrate the prognostic significance of LVI/PNI in ESCC.

Methods

A total of 195 ESCC patients underwent curative surgery from 2012 to 2018 was collected in the 2nd Affiliated Hospital of Fujian Medical University. All the patients were divided into four groups based on the status of the neurovascular invasion: (1) neither LVI nor PNI (V0N0); (2) LVI alone (V1N0); (3) PNI alone (V0N1); (4) combined LVI and PNI (V1N1). First, the analysis included the Kaplan-Meier survival estimates with the Log rank test were performed to determine median overall survival (OS) in different groups divided according to the clinical factor, respectively. And the association between OS with multi clinical factors was examined using Cox regression analysis. Next, the risk factors for recurrence in patients with V1N1 were analyzed with univariate and multivariate logistic regression analyses, respectively.

Results

The cases in V0N0, V1N0, V0N1, and V1N1 groups were 91 (46.7%), 62 (31.8%), 9 (4.6%) and 33 (16.9%), respectively. The OS in the four groups was different (P < 0.001). The 1-, 3- and 5-year OS in V0N0 group was higher than that in V1N1 group, respectively (1-year OS: 93.4% vs 75.8%, 3-year OS: 53.8 % vs 24.2%, 5-year OS: 48.1% vs 10.5%). The OS in stage I-II for patients with V1N1 was significantly lower than that in the other groups (V0N0, V1N0, V0N1) (P < 0.001). The postoperative adjuvant chemotherapy was a significant impact factor of OS for ESCC patients with V1N1 (P = 0.004). Lymphatic invasion and LVI were significantly prognosis factors associated (P = 0.036, P = 0.030, respectively). The ulcerative type is a risk factor for V1N1 occurance (P = 0.040).

Conclusions

The LVI and PNI are important prognosis factors for ESCC patients. ESCC patients with simultaneous lymphangio vascular and perineural invasion (V1N1) showed worse OS than patients with either lymphangio vascular or perineural invasion alone (V1N0 or V0N1) or none (V0N0). In addition, adjuvant chemotherapy may prolong the OS for ESCC patients with V1N1.

Prognostic impact of perineural invasion in oral cancer: a systematic review

Introduction

Numerous studies have evaluated the prognostic significance of perineural invasion (PNI) in oral cancer; however, the results are inconclusive.

Purpose

To identify the prognostic value of PNI in oral cancer through a metanalysis.

Methods

A literature review was carried out, searching the MedLine databases via Pubmed, Scielo, Lilacs, Cochrane and Websco.

Results

A total of 56 studies were included. The results indicate that PNI in oral cancer has an incidence of 28% (95% confidence interval (CI) 24-31%); 5-year survival with relative risk (RR) 0.67 (0.59-0.75); 5-year disease-free survival RR 0.71 (0.68-0.75); locoregional recurrence with RR 2.09 (1.86-2.35).

Conclusions

PNI is a negative prognostic factor in oral cancer.

Neural plasticity of the uterus: New targets for endometrial cancer?

Endometrial carcinoma is the most common gynecological malignancy in Western countries and is expected to increase in the following years because of the high index of obesity in the population. Recently, neural signaling has been recognized as part of the tumor microenvironment, playing an active role in tumor progression and invasion of different solid tumor types. The uterus stands out for the physiological plasticity of its peripheral nerves due to cyclic remodeling brought on by estrogen and progesterone hormones throughout the reproductive cycle. Therefore, a precise understanding of nerve-cancer crosstalk and the contribution of the organ-intrinsic neuroplasticity, mediated by estrogen and progesterone, of the uterine is urgently needed. The development of new and innovative medicines for patients with endometrial cancer would increase their quality of life and health. This review compiles information on the architecture and function of autonomous uterine neural innervations and the influence of hormone-dependent nerves in normal uterus and tumor progression. It also explores new therapeutic possibilities for endometrial cancer using these endocrine and neural advantages.

Perineural Invasion in Vulvar Squamous-Cell Carcinoma Is an Independent Risk Factor for Cancer-Specific Survival, but Not for Locoregional Recurrence: Results from a Single Tertiary Referral Center

Simple Summary

Vulvar squamous cell carcinoma is a rare tumor but represents a serious health issue, especially due to the increasing incidence over the past decades. Many efforts have been made to identify new prognostic and therapeutic factors and, in this context, growing evidence concerning a pivotal role of perineural invasion. With this study, we investigated the role of perineural invasion in a large cohort of FIGO stage Ib-IIIc vulvar squamous cell carcinomas and found that perineural invasion-positive tumors have more aggressive biological behaviors and showed reduced cancer-specific survival as compared to perineural invasion-negative tumors, while this feature does not appear to be related to a greater risk to develop loco-regional recurrence. Further evaluations are warranted to confirm the prognostic role of perineural invasion and its potential use to tailor adjuvant treatment.

Abstract

The aims of this study were to assess the prevalence of perineural invasion (PNI) in vulvar squamous cell carcinoma (VSCC) and its prognostic role in locoregional recurrence (LRR) and cancer-specific survival (CSS). We performed a retrospective analysis of 223 consecutive stage IB–IIIC surgically treated VSCCs at S. Anna Hospital, University of Turin, from 2000 to 2019. We identified 133/223 (59.6%) patients with PNI-positive VSCCs. PNI was associated with aggressive biological features (i.e., advanced FIGO stage, larger tumor diameter, greater depth of invasion, a higher number of metastatic lymph nodes, and lymphovascular invasion) and shorter 5-year CSS (78% vs. 90%, log-rank p = 0.02) compared with PNI-negative VSCCs. Multivariate analysis showed that PNI (HR 2.99 CI 95% 1.17–7.63; p = 0.02) and the presence of tumor cells on pathological surgical margins (HR 3.13 CI 95% 1.37–7.13; p = 0.007) are independent prognostic factors for CSS. PNI does not appear to be related to LRR, but is an independent prognostic factor for worse survival outcomes. Future studies are necessary to explore the possible value of PNI in tailoring the choice of adjuvant treatment.

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.

Molecular and Cellular Mechanisms of Perineural Invasion in Oral Squamous Cell Carcinoma: Potential Targets for Therapeutic Intervention

Simple Summary

Squamous cell carcinoma is the most common type of oral cavity cancer. It can spread along and invade nerves in a process called perineural invasion. Perineural invasion can increase the chances of tumor recurrence and reduce survival in patients with oral cancer. Understanding how oral cancer interacts with nerves to facilitate perineural invasion is an important area of research. Targeting key events that contribute to perineural invasion in oral cavity cancer may reduce tumor recurrence and improve survival. In this review, we describe the impact of perineural invasion in oral cancer and the mechanisms that contribute to perineural invasion. Highlighting the key events of perineural invasion is important for the identification and testing of novel therapies for oral cancer with perineural invasion.

Abstract

The most common oral cavity cancer is squamous cell carcinoma (SCC), of which perineural invasion (PNI) is a significant prognostic factor associated with decreased survival and an increased rate of locoregional recurrence. In the classical theory of PNI, cancer was believed to invade nerves directly through the path of least resistance in the perineural space; however, more recent evidence suggests that PNI requires reciprocal signaling interactions between tumor cells and nerve components, particularly Schwann cells. Specifically, head and neck SCC can express neurotrophins and neurotrophin receptors that may contribute to cancer migration towards nerves, PNI, and neuritogenesis towards cancer. Through reciprocal signaling, recent studies also suggest that Schwann cells may play an important role in promoting PNI by migrating toward cancer cells, intercalating, and dispersing cancer, and facilitating cancer migration toward nerves. The interactions of neurotrophins with their high affinity receptors is a new area of interest in the development of pharmaceutical therapies for many types of cancer. In this comprehensive review, we discuss diagnosis and treatment of oral cavity SCC, how PNI affects locoregional recurrence and survival, and the impact of adjuvant therapies on tumors with PNI. We also describe the molecular and cellular mechanisms associated with PNI, including the expression of neurotrophins and their receptors, and highlight potential targets for therapeutic intervention for PNI in oral SCC.

Hide-and-seek: Neurotropic squamous cell carcinoma of the periorbital region - a series of five cases and review of the literature

Squamous cell carcinoma is the second most common malignancy of the skin after basal cell carcinoma and mainly found in sun‐exposed areas such as the face. This mostly locally destructive malignancy may show invasive growth and insidious mechanisms of dissemination such as perineural invasion. Periorbital squamous cell carcinoma is associated with perineural invasion in up to 14 % of cases. Specifically in this region, the proximity to cranial nerves and therefore the associated risk of progression to the central nervous system are associated with poor prognosis. The clinically concealed character of this entity often leads to a delay in diagnosis and consequently makes complete resection and reconstruction demanding. Careful clinical evaluation often hints at perineural invasion before obtaining histology.

Aside from presenting five challenging cases, this work analyzes risk factors, clinical as well as histological features, and treatment options for periorbital squamous cell carcinoma with perineural invasion.

Hide-and-seek: Neurotropes Plattenepithelkarzinom der periorbitalen Region - eine Fallserie und Übersichtsarbeit aktueller Literatur

Das Plattenepithelkarzinom ist nach dem Basalzellkarzinom das zweithäufigste Malignom der Haut und wird vorwiegend an sonnenexponierten Stellen wie der Gesichtshaut diagnostiziert. Diese meist lokal destruktiv wachsende Malignität kann durchaus auch invasives Wachstumsverhalten, wie perineurale Ausbreitungsmechanismen, aufweisen. Das Plattenepithelkarzinom der periorbitalen Region ist in bis zu 14 % der Fälle mit perineuraler Invasion assoziiert. Vor allem in diesem Bereich birgt die anatomische Nähe zu den Hirnnerven das Risiko einer Progression Richtung zentrales Nervensystem, was mit einer schlechteren Prognose assoziiert ist. Der klinisch unauffällige Charakter dieser Entität resultiert oft in einer Verzögerung der definitiven Diagnosestellung, wodurch die vollständige Resektion und anschließende Rekonstruktion erschwert werden. Eine aufmerksame klinische Evaluierung kann bereits vor Erlangen histologischer Befunde Hinweise für ein perineurales Wachstum liefern. Neben fünf herausfordernden Fällen analysiert diese Arbeit Risikofaktoren, klinische als auch histologische Merkmale und Behandlungsoptionen des periorbitalen Plattenepithelkarzinoms mit perineuraler Invasion.

Cancer-associated keratinocytes: new members of the microenvironment in head and neck cancer

The tumor microenvironment is a complex ecosystem of malignant and nonmalignant cells and extracellular proteins that work together to enhance tumor progression. We identified a mechanism in which adjacent nonmalignant epithelium enhances invasion of squamous cell carcinoma, thereby expanding the tumor microenvironment to include cancer-associated keratinocytes.

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.

Cystatin-B Negatively Regulates the Malignant Characteristics of Oral Squamous Cell Carcinoma Possibly Via the Epithelium Proliferation/Differentiation Program

Disturbance in the proteolytic process is one of the malignant signs of tumors. Proteolysis is highly orchestrated by cysteine cathepsin and its inhibitors. Cystatin-B (CSTB) is a general cysteine cathepsin inhibitor that prevents cysteine cathepsin from leaking from lysosomes and causing inappropriate proteolysis. Our study found that CSTB was downregulated in both oral squamous cell carcinoma (OSCC) tissues and cells compared with normal controls. Immunohistochemical analysis showed that CSTB was mainly distributed in the epithelial structure of OSCC tissues, and its expression intensity was related to the grade classification. A correlation analysis between CSTB and clinical prognosis was performed using gene expression data and clinical information acquired from The Cancer Genome Atlas (TCGA) database. Patients with lower expression levels of CSTB had shorter disease-free survival times and poorer clinicopathological features (e.g., lymph node metastases, perineural invasion, low degree of differentiation, and advanced tumor stage). OSCC cell models overexpressing CSTB were constructed to assess the effects of CSTB on malignant biological behaviors and upregulation of CSTB inhibited cell proliferation, migration, and invasion in vitro. Weighted gene correlation network analysis (WGCNA) and gene set enrichment analysis (GSEA) were performed based on the TCGA data to explore potential mechanisms, and CSTB appeared to correlate with squamous epithelial proliferation-differentiation processes, such as epidermal cell differentiation and keratinization. Moreover, in WGCNA, the gene module most associated with CSTB expression (i.e., the brown module) was also the one most associated with grade classification. Upregulation of CSTB promoted the expression levels of markers (LOR, IVL, KRT5/14, and KRT1/10), reflecting a tendency for differentiation and keratinization in vitro. Gene expression profile data of the overexpressed CSTB cell line were obtained by RNA sequencing (RNA-seq) technology. By comparing the GSEA enrichment results of RNA-seq data (from the OSCC models overexpressing CSTB) and existing public database data, three gene sets (i.e., apical junction, G2/M checkpoint, etc.) and six pathways (e.g., NOTCH signaling pathway, glycosaminoglycan degradation, mismatch repair, etc.) were enriched in the data from both sources. Overall, our study shows that CSTB is downregulated in OSCC and might regulate the malignant characteristics of OSCC via the epithelial proliferation/differentiation program.

Occurrence and Prognostic Value of Perineural Invasion in Esophageal Squamous Cell Cancer: A Retrospective Study

OBJECTIVE

The aim of this study was to explore the occurrence and prognostic value of perineural invasion (PNI) as a classic tumor pathological feature in esophageal squamous cell carcinoma (ESCC).

METHODS

We retrospectively enrolled 794 ESCC patients who underwent radical esophagectomy at Shanghai Chest Hospital from 2017 to 2018. The incidence, associated factors, and prognosis of PNI were analyzed.

RESULTS

PNI was identified in 15.7% (125/794) of patients. The presence of PNI was significantly associated with depth of invasion (p < 0.001), pN stage (p = 0.008), tumor stage (p < 0.001), and lymphovascular invasion (LVI; p < 0.001). Multivariate logistic regression analysis demonstrated that advanced pT stage and LVI were independently associated with the presence of PNI, while multivariate Cox regression analysis demonstrated that PNI was not an independent risk factor for poor overall survival (OS) or recurrence-free survival (RFS) in ESCC patients (OS hazard ratio [HR] 0.688, 95% confidence interval [CI] 0.448-1.056, p = 0.087; RFS HR 0.837, 95% CI 0.551-1.273, p = 0.406). In the PNI-positive patient subgroup, adjuvant therapy was associated with better OS and RFS.

CONCLUSION

PNI correlates with, and may be a concomitant consequence of, LVI and advanced tumor invasion (T3-4) in ESCC patients. Although PNI was not identified as an independent prognostic indicator, our results suggest ESCC patients with PNI should be considered for adjuvant therapy.

Prognostic Value of Perineural Invasion in Oral Tongue Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVES

A significant number of recently published research has outlined the contribution of perineural invasion (PNI) to clinical outcomes in oral tongue squamous cell carcinoma (OTSCC), but some results remain conflicting. This study aimed to determine whether patients with OTSCC with PNI have a worse prognosis than those without PNI.

MATERIALS AND METHODS

PubMed, Embase, and the Cochrane Library were queried for potentially eligible articles published up to December 2020. The primary outcomes were the hazard ratio (HR) for locoregional recurrence, overall survival (OS), disease-free survival (DFS), and cancer-specific survival (CSS). The random-effect model was used in all analyses.

RESULTS

Seventeen studies (4445 patients) were included. Using adjusted HRs, the presence of PNI was associated with a higher risk of locoregional recurrence (HR=1.73, 95%CI: 1.07-2.79, P=0.025, I2 = 33.1%, Pheterogeneity=0.224), worse OS (HR=1.94, 95%CI: 1.39-2.72, P<0.001, I2 = 0.0%, Pheterogeneity=0.838), worse DFS (HR=2.13, 95%CI: 1.53-2.96, P<0.001, I2 = 48.4%, Pheterogeneity=0.071), and worse CSS (HR=1.93, 95%CI: 1.40-2.65, P<0.001, I2 = 25.5%, Pheterogeneity=0.251). PNI had an impact on locoregional recurrence in early-stage OTSCC but not in all stages, and on OS, DFS, and CSS in all-stage and early-stage OTSCC. The sensitivity analyses showed that the results were robust.

CONCLUSION

The presence of PNI significantly affects the locoregional recurrence and survival outcomes among patients with OTSCC.

Interactive regulation of laryngeal cancer and neuroscience

Nerve fibres are distributed throughout the body along with blood and lymphatic vessels. The intrinsic morphological characteristics of nerves and the general characteristics of secretions in the tumour microenvironment provide a solid theoretical basis for exploring how neuronal tissue can influence the progression of laryngeal cancer (LC). The central nervous system (CNS) and the peripheral nervous system (PNS) jointly control many aspects of cancer and have attracted widespread attention in the study of the progression, invasion and metastasis of tumour tissue banks. Stress activates the neuroendocrine response of the human hypothalamus-pituitary-adrenal (HPA) axis. LC cells induce nerve growth in the microenvironment by releasing neurotrophic factors (NTFs), and they can also stimulate neurite formation by secreting axons and axon guides. Conversely, nerve endings secrete factors that attract LC cells; this is known as perineural invasion (PNI) and promotes the progression of the associated cancer. In this paper, we summarize the systematic understanding of the role of neuroregulation in the LC tumour microenvironment (TME) and ways in which the TME accelerates nerve growth, which is closely related to the occurrence of LC.

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.

Multi-Site Tumour Sampling Improves the Detection of Intra-Tumour Heterogeneity in Oral and Oropharyngeal Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma (OSCC) and oropharyngeal squamous cell carcinoma (OPSCC) are very common in head and neck malignancy. Intratumour heterogeneity (ITH) may hamper their responses to treatment. Hence, novel tumour sampling methods that reflect ITH are required. In this study, we investigated the clinical significance of multi-site tumour sampling (MSTS) to detect ITH in OSCC and OPSCC.

Methods: One hundred eighty-two paired specimens were sampled by routine sampling (RS) or MSTS, respectively. Histologically, tumour grade, peri-tumoural vascular and lymphatic growth, perineural permeation, tumour necrosis, and muscle invasion were assessed. Immunohistochemically, the positive and average detection rates of P53(mutant), ki67 and CyclinD1 were detected. The exon 9 and exon 20 mutations of PIK3CA gene and the methylation status of the CDKN2A promoter were analysed.

Results: Microscopically, the detection rate of perineural permeation, the detection density of peri-tumoural vascular and lymphatic growth, necrosis and muscle invasion in MSTS were significantly more frequent than those in RP (P < 0.05, P < 0.05, P < 0.01, P < 0.01). MSTS resulted in a higher detection rate of P53 (mutant), ki67, and CyclinD1 expression than did RS, but the difference was not significant. MSTS's detection rates in PIK3CA gene mutation and gene methylation sequencing in CDKN2A gene promoter region were both higher than RP (P < 0.05, P < 0.01). To be emphasised, the hotspot mutation H1047Rwas detected in one MSTS specimen (case 24M5) but in no RS specimens.

Conclusions: This study verified that MSTS's advantage in the reflection of morphological and molecular characteristics of OSCC and OPSCC. MSTS was more representative than RP. Therefore, MSTS can compensate the RP limitations in ITH detection especially in large tumours.

The addition of chemotherapy to adjuvant radiation is associated with inferior survival outcomes in intermediate-risk HPV-negative HNSCC

BACKGROUND

Only high-risk tumors with extranodal extension (ENE) and/or positive surgical margins (PSM) benefit from adjuvant therapy (AT) with concurrent chemoradiation (CRT) compared to radiation therapy (RT) in locally advanced head and neck squamous cell carcinoma (HNSCC). Optimal treatment for intermediate-risk tumors remains controversial. We categorized patients based on their surgical pathologic risk factors and described AT treatment patterns and associated survival outcomes.

METHODS

Patients were identified from CHANCE, a population-based study, and risk was classified based on surgical pathology review. High-risk patients (n = 204) required ENE and/or PSM. Intermediate-risk (n = 186) patients had pathological T3/T4 disease, perineural invasion (PNI), lymphovascular invasion (LVI), or positive lymph nodes without ENE. Low-risk patients (n = 226) had none of these features.

RESULTS

We identified 616 HPV-negative HNSCC patients who received primary surgical resection with neck dissection. High-risk patients receiving AT had favorable OS (HR 0.50, p = 0.013) which was significantly improved with the addition of chemotherapy compared to RT alone (HR 0.47, p = 0.021). When stratified by node status, the survival benefit of AT in high-risk patients persisted only among those who were node-positive (HR: 0.17, p < 0.0005). On the contrary, intermediate-risk patients did not benefit from AT (HR: 1.26, p = 0.380) and the addition of chemotherapy was associated with significantly worse OS compared to RT (HR: 1.76, p = 0.046).

CONCLUSION

In high-risk patients, adjuvant chemoradiotherapy improved OS compared to RT alone. The greatest benefit was in node-positive cases. In intermediate-risk patients, the addition of chemotherapy to RT increased mortality risk and therefore should only be used cautiously in these patients.

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.

Role of the nervous system in cancers: a review

Nerves are important pathological elements of the microenvironment of tumors, including those in pancreatic, colon and rectal, prostate, head and neck, and breast cancers. Recent studies have associated perineural invasion with tumor progression and poor outcomes. In turn, tumors drive the reprogramming of neurons to recruit new nerve fibers. Therefore, the crosstalk between nerves and tumors is the hot topic and trend in current cancer investigations. Herein, we reviewed recent studies presenting direct supporting evidences for a better understanding of nerve-tumor interactions.

Prognostic effect of perineural invasion in surgically treated esophageal squamous cell carcinoma

Background

Although perineural invasion is a well known prognostic factor used in several cancers, its prognostic role in esophageal squamous cell carcinoma remains controversial. Here, we investigated the prognostic role of perineural invasion in surgically treated esophageal squamous cell carcinoma.

Methods

We retrospectively reviewed the medical records of 316 patients who underwent esophagectomy and lymph node dissection for esophageal squamous cell carcinoma between 2007 and 2016.

Results

Overall, 287 men (mean age: 62.73 ± 7.97 years) were included in the study. The median follow‐up period was 35.97 ± 30.99 months, perineural invasion was confirmed in 25 patients, and three‐year overall and disease‐free survival were significantly lower in the perineural invasion group than in the no‐perineural invasion group (75.9% vs. 40.0%, p < 0.001; 70.3% vs. 21.6%, p < 0.001). Cumulative incidences of locoregional recurrence and distant metastasis over three years were higher in the perineural invasion group (13.8% vs. 9.6%, p = 0.009 and 52.8% vs. 14.6%, p < 0.001). On performing multivariable analysis, perineural invasion, pathological stage, incomplete resection, and neoadjuvant therapy were adverse risk factors for disease‐free survival. The concordance index increased when perineural invasion was included in the model (0.712 vs. 0.723). On subgroup analysis, perineural invasion demonstrated a prognostic value in node‐negative patients (79.4% vs. 35.7%, p = 0.012).

Conclusions

Perineural invasion was found to be an adverse risk factor for disease‐free survival in surgically treated patients with esophageal squamous cell carcinoma. Close observation and individualized adjuvant therapy may be helpful for patients with perineural invasion.

Cancer-Associated Neurogenesis and Nerve-Cancer Cross-talk

In this review, we highlight recent discoveries regarding mechanisms contributing to nerve-cancer cross-talk and the effects of nerve-cancer cross-talk on tumor progression and dissemination. High intratumoral nerve density correlates with poor prognosis and high recurrence across multiple solid tumor types. Recent research has shown that cancer cells express neurotrophic markers such as nerve growth factor, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor and release axon-guidance molecules such as ephrin B1 to promote axonogenesis. Tumor cells recruit new neural progenitors to the tumor milieu and facilitate their maturation into adrenergic infiltrating nerves. Tumors also rewire established nerves to adrenergic phenotypes via exosome-induced neural reprogramming by p53-deficient tumors. In turn, infiltrating sympathetic nerves facilitate cancer progression. Intratumoral adrenergic nerves release noradrenaline to stimulate angiogenesis via VEGF signaling and enhance the rate of tumor growth. Intratumoral parasympathetic nerves may have a dichotomous role in cancer progression and may induce Wnt-β-catenin signals that expand cancer stem cells. Importantly, infiltrating nerves not only influence the tumor cells themselves but also impact other cells of the tumor stroma. This leads to enhanced sympathetic signaling and glucocorticoid production, which influences neutrophil and macrophage differentiation, lymphocyte phenotype, and potentially lymphocyte function. Although much remains unexplored within this field, fundamental discoveries underscore the importance of nerve-cancer cross-talk to tumor progression and may provide the foundation for developing effective targets for the inhibition of tumor-induced neurogenesis and tumor progression.

All HPV-negative head and neck cancers are not the same: Analysis of the TCGA dataset reveals that anatomical sites have distinct mutation, transcriptome, hypoxia, and tumor microenvironment profiles

PURPOSE

Head and neck squamous cell carcinoma (HNSCC) affects various anatomical sites, which often dictates whether the cancer is managed with primary surgery or radiation. This study aimed to assess differences in single nucleotide variation (SNV), copy number, mRNA abundance, methylation, and tumor microenvironment (TME) between HPV-negative oral cavity (OC), oropharyngeal (OPC), hypopharyngeal (HPC), and laryngeal (LC) cancers within The Cancer Genome Atlas (TCGA).

METHODS

We downloaded the clinical information and molecular data for the TCGA HNSCC cohort from the data portal and published literature. The TME was estimated using mRNA abundance data. We conducted our analyses within the Bioconductor statistical framework in the R environment. CNA and mRNA abundance results were correlated and grouped with SNV results for downstream pathway analysis.

RESULTS

LC had a higher mutational burden than OC and OPC (p <10^-4). LC tumors were enriched in CSMD3, NSD1, DCHS2 and ANK2 SNVs, while OC tumors were enriched in CASP8 SNVs (FDR < 0.1). LCs were enriched for neuronal and glycosylation pathways, while OCs were enriched for extracellular matrix pathways. B cells and endothelial cells were more abundant in LC while monocytes were more abundant in OC (FDR < 0.1). OPC was the most hypoxic, followed by OC then LC (FDR < 0.05). OC had greater methylation of Hox genes than LC. Subsite analysis revealed that oral tongue cancers had fewer CASP8 and FBN2 mutations and higher dendritic cell abundance than other oral cavity cancers.

CONCLUSIONS

We identified significant genomic, transcriptional, and microenvironmental differences between HPV-negative HNSCC. Further study is warranted to determine if these findings portend differential response to specific treatment modalities.

Asparagine Synthetase-Mediated l-Asparagine Metabolism Disorder Promotes the Perineural Invasion of Oral Squamous Cell Carcinoma

Dysregulated amino acids metabolism reciprocally interplays with evolutionary phenotypic characteristics of cancer cells to enhance metastasis. The high metastasis potential of oral squamous cell carcinoma (OSCC) can manifest with perineural invasion (PNI). We here aimed to determine the role of amino acids metabolism in OSCCs with different PNI statuses. Targeted metabolomics was used to quantify 48 amino acids in 20 fresh OSCC samples and 25 amino acids were successfully detected, within which 9 were significantly up-regulated in PNI positive (PNI+) samples. As its highest area under the curve value (0.9063), l-asparagine was selected as the biomarker to distinguish PNI+ from PNI negative (PNI-). Then, the key enzyme of l-asparagine, asparagine synthetase (ASNS), was investigated using immunohistochemistry with 86 OSCC patients. The results showed that ASNS mainly expressed in tumor epitheliums and positively correlated with lymph node metastasis and PNI. Moreover, subgroup survival analysis revealed that ASNS expression combined with PNI status significantly improved their prognostic value, which was confirmed by the TCGA OSCC cohort (n = 279). To validate whether ASNS promotes PNI, we determined ASNS expression levels in five OSCC cell lines and one normal oral keratinocyte, and HSC3 showed the lowest ASNS level but CAL33 had the highest. Therefore, HSC3 and CAL33 (or PBS as control) were selected and injected separately into sciatic nerves to construct the in vivo PNI mouse models. Although both models eventually developed the hind-limb paralysis, nerve dysfunction in the CAL33 model progressed significantly earlier than HSC3 (Day 9 vs. Day 24). Besides, CAL33 migrated significantly farther than HSC3 in the nerve microenvironment (P = 0.0003), indicating high ASNS expression is indispensable for OSCC progression, especially PNI formation, through l-asparagine metabolism alteration. This study provides novel insights into how amino acids metabolism disorders alter tumor neurotropism which helps cancer metastasis.

Oligometastases in head and neck carcinoma and their impact on management

Historically, patients with head and neck squamous cell carcinoma (HNSCC) with distant metastases were regarded as palliative. Oligometastasis (OM) refers to patients with a limited number of distant metastatic deposits. Treatment of patients with OMs has been reported in patients with lung, colon, breast, prostate and brain malignancies. Selected patients with oligometastatic HNSCC have a higher probability of durable disease control and cure and these patients should be treated aggressively. Treatment options for patients with HNSCC OMs include single or combinations of the three arms of cancer treatment, that is surgery, radiotherapy and chemotherapy/immunotherapy. To date, there are limited studies reporting the management of OM with head and neck malignancy. This review will give insights into the management of OMs in HNSCC.

Simultaneous Treatment with Soluble Forms of GAS1 and PTEN Reduces Invasiveness and Induces Death of Pancreatic Cancer Cells

Introduction

Pancreatic carcinoma cells exhibit a pronounced tendency to invade along and through intra and extrapancreatic nerves, even during the early stages of the disease, a phenomenon called perineural invasion (PNI). Thus, we sought to determine the effects of the simultaneous expression of soluble forms of GAS1 and PTEN (tGAS1 and PTEN-L) inhibiting tumor growth and invasiveness.

Materials and Methods

We employed a lentiviral system to simultaneously express tGAS1 and PTEN-L; in order to determine the effects of the treatments, cell viability and apoptosis as well as the expression of the transgenes by ELISA and intracellular signaling as ascertained by the activation of AKT and ERK1/2 were measured; cell invasiveness was determined using a Boyden chamber assay; and the effects of the treatment were measured in vivo in a mouse model.

Results

In the present work, we show that the combined treatment with tGAS1 and PTEN-L inhibits the growth of pancreatic cancer cells, by reducing the activities of both AKT and ERK 1/2, decreases cell invasiveness, and restrains tumor growth in a mouse model.

Conclusion

The combined administration of tGAS1 and PTEN-L could be a valuable adjunct therapy for the treatment of pancreatic cancer.

A HPV16-related prognostic indicator for head and neck squamous cell carcinoma

Background

The human papillomavirus (HPV) is emerging as an important risk factor in head and neck squamous cell carcinoma (HNSCC) patients. This has been observed particularly in the case of HPV16. The HPV16+ HNSCC subtype has distinct pathological, clinical, molecular, and prognostic characteristics. This study aimed to identify potential microRNAs (miRNAs) and their roles in HPV16+ HNSCC progression.

Method

miRNA, mRNA and the clinical data of 519 HNSCC and 44 HNSCC-negative samples were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed miRNAs (DEMs) in HPV16-related HNSCC tissues with prognostic value were selected. DEM levels were assessed based on clinicopathological parameters and overall survival (OS). Target genes were also predicted and functional analysis based on Gene Set Enrichment Analysis (GSEA) were then performed.

Results

In HPV16+ HNSCC tissues, miR-99a-3p and miR-4746-5p were significantly upregulated. In contrast, miR-411-5p was shown to be downregulated. miR-99a-3p^highmiR-411-5p^lowmiR-4746-5p^high expression could estimate improved OS and low frequent perineural invasion (PNI). Predicted target genes were enriched in cell growth, neuroepithelial cell differentiation, MAPK and FoxO signaling pathways. Epithelial mesenchymal transition (EMT) gene set and invasion related genes were downregulated in miR-99a-3p^highmiR-411-5p^lowmiR-4746-5p^high HNSCC patients.

Conclusion

miR-99a-3p, miR-411-5p and miR-4746-5p might participate in HPV16+ HNSCC progression through EMT related pathways and affect prognosis.

Stage-dependent angiopoietin-Tie2 and nitric oxide signaling of erythrocytes in response to surgical trauma in head and neck cancer

Background

Angiopoietin-Tie2 and nitric oxide pathway is crucial in tumor angiogenesis and closely correlates with tumor development, growth, and metastasis. This study aimed to investigate the angiopoietin-Tie2 and nitric oxide signaling of the erythrocyte membrane in response to surgical trauma in head and neck cancer.

Methods

We prospectively enrolled the patients with histology-proven head and neck squamous cell carcinoma undergoing surgical resection of primary tumors at the medical center between August and November 2019. We measured the preoperative and postoperative levels of angiopoietin-1, angiopoietin-2 in plasma using enzyme-linked immunosorbent assays, nitric oxide in plasma using nitrate/nitrite colorimetric assays, and Tie2 phosphorylation in erythrocyte membrane using Western blotting.

Results

The plasma angiopoietin-1 was downregulated from the median 971.3 pg/mL (interquartile range [IQR] 532.1–1569.3) to 417.9 (IQR 270.5–597.3) after tumor resection (p = 0.0020). Conversely, the plasma angiopoietin-2 was enhanced from 1173.6 pg/mL (IQR 977.7–1450.2) to 2353.7 (IQR 1352.4–2954.3) after surgery (p = 0.0021), with a concomitant increase in plasma nitric oxide level from 7.73 μM (IQR 5.39–10.06) to 10.50 (IQR 7.65–14.18) after surgical resection (p = 0.0093). Subgroup analyses further showed the angiopoietin-Tie2 and nitric oxide signaling was significant only in stage III and IV cancer.

Conclusions

The dynamic change of angiopoietin-Tie2 signaling in the erythrocyte membrane along with the enhanced nitric oxide in plasma after tumor resection suggests erythrocytes play a significant role in modulating surgery-induced angiogenesis, which may provide a novel marker for cancer surveillance and control.

Histological features and survival in young patients with HPV-negative oral squamous cell carcinoma

OBJECTIVES

The frequency of oral squamous cell carcinoma in young adults has increased in the last decades, and there are conflicting results in literature about its prognosis in young subjects. The aim of this study was to analyse the clinical and pathological features of oral squamous cell carcinoma in a cohort of young adults in order to investigate the presence of new independent prognostic markers.

MATERIALS AND METHODS

Only HPV-negative young patients (under 40-year-old) affected by oral squamous cell carcinoma were considered in this study. Clinical and pathological data were collected. Patients were re-staged according to the 8th edition of AJCC.

RESULTS

Overall, 66 patients were considered in this study. Perineural invasion significant correlated with both 7th and 8th edition of AJCC, and lymphovascular invasion (p-value < .05). The multivariate survival analysis showed that patients with perineural invasion had a significant worse prognosis (HR = 6.384 95% C.I. 1.304-31.252; p-value = .022).

CONCLUSIONS

Perineural invasion emerged as an independent prognostic factor for disease-specific survival in young patients with oral squamous cell carcinoma. Furthermore, the evaluation of this parameter is simple, inexpensive and can be used to augment the risk stratification of oral cancer based on the 8th edition of AJCC.

Perineural invasion in oral squamous cell carcinoma: Incidence, prognostic impact and molecular insight

BACKGROUND

The objective of this study was to characterise the incidence and prognostic correlation of perineural invasion (PNI) in oral squamous cell carcinoma and determine whether nerve growth factor and its receptor tyrosine Kinase A expression could be used as biological markers for PNI.

METHODS

A retrospective review of pathology reports of 430 patients with oral squamous cell carcinoma who were treated from 1992 to 2014 in Tayside, Scotland, was carried out. The expression of nerve growth factor and tyrosine kinase A was assessed with immunohistochemistry in 132 tissue sections of oral squamous cell carcinoma.

RESULTS

Perineural invasion was identified in 17.4% of oral squamous cell carcinomas. High expression of nerve growth factor and tyrosine kinase A was seen in 84% and 92% of oral squamous cell carcinoma, respectively. Tumours with PNI expressed nerve growth factor and tyrosine kinase A with a greater frequency than tumours without PNI. PNI and high expression of nerve growth factor were significantly associated with pain. PNI was significantly associated with stage IV tumours and poor disease-specific survival.

CONCLUSIONS

A higher level of expression of nerve growth factor and tyrosine kinase A may predict PNI and therefore may be considered as biological markers for PNI in oral squamous cell carcinoma. PNI and nerve growth factor overexpression may contribute to the pain generation in oral cancer patients. PNI and nerve growth factor expression can predict the aggressiveness and prognosis of oral squamous cell carcinoma patients.

Benefit from surgery with additional radiotherapy in N1 head and neck cancer at the time of IMRT: A population-based study on recent developments

BACKGROUND

Currently, the role of adjuvant irradiation in head and neck cancer (HNC) patients with N1-lymph node status is not clarified.

OBJECTIVES

To assess the population-based effect of recent developments in radiotherapy such as intensity-modulated radiotherapy (IMRT) in relation to overall survival (OS) together with surgery in N1 HNC patients.

MATERIALS AND METHODS

We used 9,318 HNC cases with pT1/2 N0/1 disease from German cancer registries. Time of diagnosis ranged from January 2000 to December 2014, which we divided into three periods: (low [LIA] vs intermediate [IA] vs high [HIA] IMRT availability period) based on usage of IMRT in Germany. For each period, we examined a possible association between treatment (surgery vs. surgery and radiotherapy) in terms of OS. Statistical analyses included Kaplan-Meier and multivariate Cox regression (models adjusted for HPV-related cancer site).

RESULTS

Temporal analysis revealed increasing usage of IMRT in Germany. In patients with N1 tumours, a comparison of patients treated with and without radiotherapy during the HIA period showed a superiority of the combined treatment as opposed to surgery alone (HR 0.54, 95%CI: 0.35-0.85, p = 0.003). The survival analyses related to treatments in terms of period underlined the superiority of surgery plus radiotherapy between periods IA and HIA (p = 0.03).

CONCLUSION

The advent of IMRT, additional radiotherapy may present a survival advantage in patients with N1 HNC when combined with surgery.

Recent Advances in Head and Neck Tumor Microenvironment-Based Therapy

Head and neck squamous cell carcinomas (HNSCCs) are a group of heterogeneous aggressive tumors affecting more than half a million patients worldwide annually. While the tobacco- and alcohol-associated HNSCC tumors are declining, human papillomavirus (HPV)-induced tumors are on rise. Despite recent advances in multimodality therapeutic interventions including surgery in combination with chemoradiation therapy (CRT), the overall 5-year survival has not improved more than 50%. The underlying reasons for this dismal prognosis is the intrinsic or acquired resistance to CRT. While previous studies were focused to target tumor cells, recent findings have implicated the involvement of tumor microenvironment (TME) on tumor progression and response to therapy. HNSCC TME includes cancer-associated fibroblasts (CAFs), endothelial cells, immune cells, endocrine cells, and the extracellular matrix (ECM) proteins including collagen and fibronectin. Understanding the crosstalk between TME and cancer cells is important to formulate more effective novel therapies and to overcome resistance mechanisms. Here, we summarized the current literature on recent advances on HNSCC TME with special emphasis on novel cell-cell interactions and therapies currently under development.

Nerve growth factor-induced migration in oral and salivary gland tumour cells utilises the PI3K/Akt signalling pathway: Is there a link to perineural invasion?

OBJECTIVES

The aims of this study were to investigate the role of nerve growth factor on perineural invasion in oral and salivary gland tumour cell lines and whether there is an involvement of PI3K/Akt pathway.

MATERIALS AND METHODS

Four cell lines were investigated: HSG and TYS (salivary gland tumours), SAS-H1 (oral squamous cell carcinoma) and HaCaT (human skin keratinocyte). Initially, Boyden chamber assay was done to examine the effect of different concentration of nerve growth factor on cell migration. Western blot/ immunofluorescence techniques were used to investigate the phosphorylation status of the Akt pathway within the cells in response to nerve growth factor. The effect of this growth factor and the addition of an Akt inhibitor on cell morphology and migration were also examined using scatter/scratch assays.

RESULTS

Nerve growth factor triggered the PI3K/Akt pathway in oral and salivary tumour cells and induced oral and salivary tumour cell scattering and migration. Inhibitor assays confirmed that oral and salivary gland tumour cell scattering and migration is Akt dependent.

CONCLUSIONS

Nerve growth factor can stimulate scattering and migration in cells derived from oral and salivary gland tumours, thereby potentially enhancing perineural invasion. Phosphorylated Akt controls cancer cell migration and scattering. Blocking the Akt pathway may inhibit cell migration and therefore perineural invasion and metastasis.

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.

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.

Integrating Clinical and Genetic Analysis of Perineural Invasion in Head and Neck Squamous Cell Carcinoma

Introduction: Perineural invasion (PNI), a key pathological feature of head and neck squamous cell carcinoma (HNSCC), predicts poor survival. However, the associated clinical characteristics remain uncertain, and the molecular mechanisms are largely unknown. Materials and methods: HNSCC gene expression and corresponding clinical data were downloaded from The Cancer Genome Atlas (TCGA). Prognostic subgroup analysis was performed, and potential PNI risk factors were assessed with logistic regression. PNI-associated gene coexpression modules were identified with weighted gene coexpression network analysis (WGCNA), and key module gene functions and the roles of non-malignant cells in PNI were evaluated with a single-cell transcriptomic dataset (GSE103322). Results: PNI was significantly inversely associated with overall survival (HR, 2.08; 95% CI, 1.27 to 3.40; P = 0.004), especially in advanced patients (HR, 2.62; 95% CI, 1.48 to 4.64; P < 0.001). Age, gender, smoking history, and alcohol history were not risk factors. HPV-positive cases were less likely than HPV-negative cases to develop PNI (OR, 0.28; 95% CI, 0.09 to 0.76; P = 0.017). WGCNA identified a unique significantly PNI-associated coexpression module containing 357 genes, with 12 hub genes (TIMP2, MIR198, LAMA4, FAM198B, MIR4649, COL5A1, COL1A2, OLFML2B, MMP2, FBN1, ADAM12, and PDGFRB). Single-cell transcriptomic data analysis revealed that the genes in the PNI-associated module correlated with the signatures "EMT," "metastasis," and "invasion." Among non-malignant cells, fibroblasts had relatively high expression of the key genes. Conclusion: At the molecular and omic levels, we verified that PNI in HNSCC is a process of invasion rather than simple diffusion. Fibroblasts probably play an important role in PNI. Novelty & Impact Statements  The study is a thorough analysis of PNI in HNSCC from the clinical level to the molecular level and presents the first description of cancer-related PNI from the omics perspective to date as far as we know. We verified that PNI in HNSCC is a process of invasion rather than simple diffusion, at the molecular and omic levels. Fibroblasts were found to probably play an important role in PNI by analyzing single-cell transcriptomic data.

Immune-relevant aspects of murine models of head and neck cancer

Head and neck cancers (HNCs) cause significant mortality and morbidity. There have been few advances in therapeutic management of HNC in the past 4 to 5 decades, which support the need for studies focusing on HNC biology. In recent years, increased recognition of the relevance of the host response in cancer progression has led to novel therapeutic strategies and putative biomarkers of tumor aggressiveness. However, tumor-immune interactions are highly complex and vary with cancer type. Pre-clinical, in vivo models represent an important and necessary step in understanding biological processes involved in development, progression and treatment of HNC. Rodents (mice, rats, hamsters) are the most frequently used animal models in HNC research. The relevance and utility of information generated by studies in murine models is unquestionable, but it is also limited in application to tumor-immune interactions. In this review, we present information regarding the immune-specific characteristics of the murine models most commonly used in HNC research, including immunocompromised and immunocompetent animals. The particular characteristics of xenograft, chemically induced, syngeneic, transgenic, and humanized models are discussed in order to provide context and insight for researchers interested in the in vivo study of tumor-immune interactions in HNC.

Significance of perineural and lymphovascular invasion in locally advanced rectal cancer treated by preoperative chemoradiotherapy and radical surgery: Can perineural invasion be an indication of adjuvant chemotherapy?

PURPOSE

To investigate the prognostic significance of lymphovascular space invasion (LVI) and perineural invasion (PNI) in rectal cancer.

METHODS AND MATERIALS

Clinical data of 1,232 stage II-III rectal cancer patients from six tertiary institutions were analyzed. All patients were treated by long-course preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME). Adjuvant systemic chemotherapy was performed for 962 (78.1%) patients according to the multidisciplinary team's decision. Treatment outcomes and prognostic factors were evaluated according to the lymphovascular invasion (LVI) and perineural invasion (PNI) status.

RESULTS

Five-year overall survival (OS) and recurrence-free survival (RFS) rates of the entire cohort were 84.1% and 71.1%, respectively. There is a significant difference in 5-year OS among both-absent, LVI+ only, PNI+ only, and both-present groups (89.1% vs. 77.9% vs. 67.6% vs. 56.2%; p < 0.001). RFS at five years was significantly different among both-absent, LVI+ only, PNI+ only, and both-present groups (78.7% vs. 58.7% vs. 44.6% vs. 38.6%; p < 0.001). The 5-year distant failure-free survival (DFFS) rate was also significantly different among four groups (84.6% vs. 61.4% vs. 54.2% vs 48.6%; p < 0.001). Although adjuvant chemotherapy did not affect 5-year DFFS in the entire cohort, adjuvant chemotherapy significantly reduced the distant failure rate in patients with PNI+ patients (44.9% vs. 54.6%, p = 0.048), not LVI+ patients (65.0% vs. 56.1%, p = 0.487).

CONCLUSION

Compared to LVI, PNI is a more significant prognostic factor in stage II-III rectal patients treated by preoperative CRT and TME surgery. The status of PNI rather than LVI could be an indicator for identifying patients who could benefit from adjuvant systemic chemotherapy.

Perineural invasion of cancer: a complex crosstalk between cells and molecules in the perineural niche

Perineural invasion (PNI) can be found in a variety of malignant tumors. It is a sign of tumor metastasis and invasion and portends the poor prognosis of patients. The pathological description and clinical significance of PNI are clearly understood, but exploration of the underlying molecular mechanism is ongoing. It was previously thought that the low-resistance channel in the anatomic region led to the occurrence of PNI. However, with rapid development of precision medicine and molecular biology, we have gradually realized that the occurrence of PNI is not the result of a single factor. The latest study suggests that PNI of cancer is a continuous and multistep process. A specific peripheral microenvironment, also called the perineural niche, is formed by neural cells, supporting cells, recruited inflammatory cells, altered extracellular matrix, blood vessels, and immune components in the background of carcinoma. Various soluble signaling molecules and their receptors comprise a complex signal network, which achieves the interaction between nerve and tumor. Nerve cells and tumor cells can interact directly or through the opening and closing of the signal transduction pathways and/or the recognition and response of the ligands and receptors. The information is transferred to the targets accurately and effectively, leading to the specific interactions between the nerve cells and the malignant tumor cells. PNI occurs through changes in nerve cells and supporting cells in the background of cancer; change and migration of the perineural matrix; enhancement of the viability, mobility, and invasiveness of the tumor cells; injury and regeneration of nerve cells; interaction, chemotactic movement, contact, and adherence of the nerve cells and the tumor cells; escape from autophagy, apoptosis, and immunological surveillance of tumor cells; and so on. Certainly, exploring the mechanism of PNI clearly has great significance for blocking tumor progression and improving patient survival. The current review aims to elucidate the cellular and molecular mechanisms of PNI, which may help us find a strategy for improving the prognosis of malignant tumors.

A gene expression profile associated with perineural invasion identifies a subset of HNSCC at risk of post-surgical recurrence

OBJECTIVES

Perineural invasion (PNI) is a common histopathological finding in head and neck squamous cell carcinoma (HNSCC). We aimed to explore the molecular mechanisms involved in PNI and the role of PNI as an aggressive pathological feature.

MATERIALS AND METHODS

We used data from The Cancer Genome Atlas (TCGA) to relate the histological presentation of 528 HNSCC tumours to clinical, whole genome expression and proteomic data.

RESULTS

We identified a specific gene expression profile highly enriched in genes related to muscle differentiation/function and associated with PNI in HNSCC. We explored the clinical significance of this profile in three groups of HNSCC tumours stratified according to their low, intermediate or high risk of post-surgical recurrence. In the "low-risk" group, defined as tumours indicated for surgery without adjuvant radiotherapy (n = 51), the PNI gene expression profile identified a subset of HNSCC with a higher rate of tumour recurrence, decreased Disease Free Survival (DFS) and Overall Survival (OS) (p < 0.0001 and p = 0.0064, respectively). Comparable results were observed in "intermediate risk" tumours (n = 112), but not in "high risk" tumours (n = 147), whose prognosis was driven by the presence of lymph node extracapsular spread. Finally, we found that tumours with histological PNI had increased activation levels of the Akt/PKB and mTOR (mammalian Target Of Rapamycin) kinases.

CONCLUSION

PNI is characterised by a specific gene expression profile and distinct biological characteristics. Analysing the PNI gene expression profile holds potential for therapeutic stratification of HNSCC and identification of a subset of tumours with a higher risk of recurrence.