Dual S-100-AE1/3 Immunohistochemistry to Detect Perineural Invasion in Nonmelanoma Skin Cancers

Perineural invasion in cervical cancer

Perineural invasion (PNI), the neoplastic infiltration of peripheral nerves, is recognized as the fourth mode of tumor metastasis and invasion. PNI is defined as a critical pathological feature observed across various cancers and is associated with poor prognosis. Recent studies have demonstrated that PNI also occurs in cervical cancer. Nerve-sparing radical hysterectomy (NSRH) has been promoted as the preferred approach for radical surgical resection of cervical cancer, as it reduces postoperative complications such as bladder, rectal, and sexual dysfunction. However, the presence of PNI has become a contraindication for NSRH. Despite the increasing volume of studies on PNI, the underlying mechanisms of its pathogenesis remain largely unclear. In this review, we discuss the innervation, characteristics, preoperative prediction and diagnosis of PNI in cervical cancer, along with its underlying mechanism, paving the way for advancements in treatment strategies and improving the prognosis for cervical cancer patients.

Understanding the role of nerves in head and neck cancers - a review

Worldwide, head and neck cancers (HNCs) account for approximately 900,000 cases and 500,000 deaths annually, with their incidence continuing to rise. Carcinogenesis is a complex, multidimensional molecular process leading to cancer development, and in recent years, the role of nerves in the pathogenesis of various malignancies has been increasingly recognized. Thanks to the abundant innervation of the head and neck region, peripheral nervous system has gained considerable interest for its possible role in the development and progression of HNCs. Intratumoral parasympathetic, sympathetic, and sensory nerve fibers are emerging as key players and potential targets for novel anti-cancer and pain-relieving medications in different tumors, including HNCs. This review explores nerve-cancer interactions, including perineural invasion (PNI), cancer-related axonogenesis, neurogenesis, and nerve reprogramming, with an emphasis on their molecular mechanisms, mediators and clinical implications. PNI, an adverse histopathologic feature, has been widely investigated in HNCs. However, its prognostic value remains debated due to inconsistent results when classified dichotomously (present/absent). Emerging evidence suggests that quantitative and qualitative descriptions of PNI may better reflect its clinical usefulness. The review also examines therapies targeting nerve-cancer crosstalk and highlights the influence of HPV status on tumor innervation. By synthesizing current knowledge, challenges, and future perspectives, this review offers insights into the molecular basis of nerve involvement in HNCs and the potential for novel therapeutic approaches.

Perineural Invasion in Cervical Cancer: A Hidden Trail for Metastasis

Perineural invasion (PNI), the neoplastic invasion of nerves, is an often overlooked pathological phenomenon in cervical cancer that is associated with poor clinical outcomes. The occurrence of PNI in cervical cancer patients has limited the promotion of Type C1 surgery. Preoperative prediction of the PNI can help identify suitable patients for Type C1 surgery. However, there is a lack of appropriate preoperative diagnostic methods for PNI, and its pathogenesis remains largely unknown. Here, we dissect the neural innervation of the cervix, analyze the molecular mechanisms underlying the occurrence of PNI, and explore suitable preoperative diagnostic methods for PNI to advance the identification and treatment of this ominous cancer phenotype.

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.

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.

Squamous and basal cell carcinoma with perineural invasion: pathophysiology and presentations

Squamous and basal cell carcinomas with perineural invasion are typically difficult to treat because of their propensity to metastasize, their aggressive nature, and the concept of skip lesions. Perineural invasion is an under-recognized and underdiagnosed condition even though the literature points to its high rate of incidence in squamous cell carcinoma and a nonnegligible incidence rate in basal cell carcinoma. Perineural invasion has been linked to higher recurrence rates and poorer prognosis. This review has been written to aid clinicians in identifying and managing the condition as early as possible by describing the clinical and microscopic manifestations of perineural invasion.

Integrin β4 Is an Effective and Efficient Marker in Synchronously Highlighting Lymphatic and Blood Vascular Invasion, and Perineural Aggression in Malignancy

Lymphovascular invasion (LVI) and perineural invasion (PNI) are 2 important pathologic parameters and need to be accurately assessed in multiple malignancies. Integrin β4, a member of the integrin family, has been reported to be positively expressed in vascular endothelia, peripheral nerves, and a collection of epithelia. However, little is known about the effectiveness of β4 immunostaining on the recognition of LVI and PNI. Herein, we explored the applicability of β4 immunostaining in stomach, thyroid, and breast cancers. Parallel immunostaining of D2-40, CD34, and S-100 was performed as controls for lymphatic endothelia, vascular endothelia, and neural fibers, respectively. The results demonstrated that β4 concurrently stained the lymphatic and vascular endothelia, and the peripheral nerves. Both LVI and PNI were clearly and accurately outlined by β4 immunostaining. β4 was also expressed in the majority of tumor cells, enabling recognition of LVI and PNI encroached by small tumor clusters. In contrast to D2-40 and CD34, β4 staining was not observed in stromal cells, and therefore it facilitated differentiation between the shrinkage cleft and LVI. According to our results, β4 staining strikingly increased the diagnostic accuracy and interobserver concordance for LVI and PNI compared with hematoxylin and eosin staining alone. Finally, the applicability of β4 was confirmed in 9 other types of malignancies, including cancers of the colon, prostate, esophagus, lung, kidney, uterus, tongue, bladder, and liver. Collectively, β4 is a reliable marker for synchronous detection and diagnosis of LVI and PNI.

Neurotrophin Receptors and Perineural Invasion: Analyses in Select Lineage-Unrelated Cutaneous Malignancies With a Propensity for Perineural Invasion

In this chapter, we parse the literature on neurotrophins that have been implicated in the pathogenesis of perineural invasion (PNI) in select lineage-unrelated malignancies. We also detail evidence linking neurotrophins and their receptors (TrkA, RET, p75NGFR, and NCAM) to the pathogenesis of PNI in desmoplastic melanoma and cutaneous squamous cell carcinoma-both malignancies with an established propensity for PNI. Lastly, the clinical potential of neurotrophins as receptors for targeted therapies is explored.

Interobserver Variation Among Pathologists in Evaluating Perineural Invasion for Oral Squamous Cell Carcinoma

The aims of this study are as follows: (1) to assess variations among pathologists in evaluating perineural invasion (PNI) in oral squamous cell carcinoma (OSCC), (2) to survey PNI criteria used by pathologists and how they came to adopt those criteria. An electronic survey was sent to 363 oral and/or surgical pathologists. Eligibility criteria included pathology board certification. The survey participants were asked to rate whether PNI was present, absent, or uncertain for 15 provided photomicrographs, which depicted various types of tumor-nerve relationships without excessive desmoplasia or lymphocytic host response. The survey obtained information regarding demographics, whether PNI criteria were taught during residency, criteria used by participants to evaluate PNI, how the participants developed their criteria, and agreement with six proposed PNI definitions. 88 pathologists completed the survey. The participants included 47 males and 41 females, with average age = 49 years and average practice experience = 17 years. Practice settings included dental school (40 %), medical school (36 %), private pathology lab (13 %), and other (11 %). Agreement between participants in rating PNI status for the provided images was fair (κ = .38, 95 % CI .37-.39). 56 % of respondents indicated that they were taught PNI criteria during residency training. The basis for criteria currently used by participants included residency training (n = 42), published literature (n = 29), and own experience/views (n = 32). Agreement regarding six proposed PNI definitions was slight (κ = .10, 95 % CI .08-.11). In conclusion, interobserver agreement in assessing PNI status was fair. Our results suggest that more widely accepted, objective, and reproducible criteria are needed for evaluating PNI in OSCC.

Intracranial Management of Perineural Spread in the Trigeminal Nerve

Since the mid-1960s surgeons have attempted to cure intracranial perineural spread (PNS) of cutaneous malignancies. Untreated patients with trigeminal PNS die from brainstem invasion and leptomeningeal disease. It was understood that resection with clear margins was potentially curative, but early surgical attempts were unsuccessful. The prevailing wisdom considered that this surgery failed to improve the results achieved with radiation therapy alone and was associated with high morbidity. However, with improved imaging, surgical equipment, and better understanding of cavernous sinus (CS) anatomy and access, contemporary surgeons can improve outcomes for this disease. The aim of this paper is to describe a technique to access the interdural compartment of the CS and treat PNS of cutaneous squamous cell carcinoma (cSCC) in the intracranial trigeminal nerve and ganglion. It is based on the experience of the Queensland Skull Base Unit, Australia in managing PNS of cutaneous squamous cell carcinoma of the head and neck (cSCCHN).

Perineural invasion in cutaneous squamous cell carcinoma: role of immunohistochemistry, anatomical site, and the high-affinity nerve growth factor receptor TrkA

Perineural invasion (PNI) has been recently added to the American Joint Committee on Cancer cutaneous squamous cell carcinoma (cSCC) staging criteria as a high-risk tumor characteristic and is purportedly more common in cSCCs of the head and neck (H&N). Expression of the high-affinity nerve growth factor receptor TrkA has been shown to be associated with PNI in noncutaneous neoplasms. Given this, we sought to ascertain the incidence of PNI in cSCCs using double immunostaining (DIS) and to investigate PNI's relationship with TrkA and established histopathologic prognosticators. Fifty-seven cSCCs from the H&N and 53 from non-H&N areas were immunohistochemically analyzed for PNI (DIS with S-100 and p63) and TrkA expression. Comparing H&N versus non-H&N areas, using hematoxylin and eosin, PNI was detected in 11% versus 6% cases, respectively, and, using DIS, in 23% versus 15%, respectively, with significant disagreement between both methods (κ = 0.47; P = .002). There was a 2.33-fold increase in PNI detection with DIS compared to hematoxylin and eosin (95% confidence interval, 1.12-4.87; P = .02). TrkA expression was 1.96 times more frequently observed in cSCCs from the H&N compared to those from non-H&N areas (P = .01). Regardless of site, TrkA expression was associated with decreased degree of differentiation (odds ratio, 6.46; P = .0006) and high-risk morphologic variants (odds ratio, 6.53; P = .002) but not significantly associated with PNI (P = .33). Increased PNI detection with DIS underscores the adjunctive utility of immunohistochemistry in microstaging. Significantly more common TrkA expression in cSCCs of the H&N argues in favor of heterogeneity among SCCs from different anatomical sites.