The evolving molecular characterisation, histological criteria and nomenclature of adenoid ameloblastoma as a World Health Organisation tumour type.

Adenoid ameloblastoma (AA) was recently recognised as a separate tumour type in the most recent World Health Organisation (WHO) classification of head and neck tumours. This decision has been considered controversial by several groups, who have described AA as a subtype of ameloblastoma, a hybrid odontogenic tumour or to fall within the spectrum of other recognised odontogenic tumours, including dentinogenic ghost cell tumour and adenomatoid odontogenic tumour. Here we review the reasons for the WHO decision to classify AA as a separate tumour type. We also critique molecular and histological findings from recent reports published since the WHO classification. While acknowledging that the classification of tumours is constantly evolving, the balance of current evidence suggests that AA should remain a distinct tumour type, and not a subtype of ameloblastoma, pending further molecular characterisation.

Computational pathology in cancer diagnosis, prognosis, and prediction - present day and prospects.

Computational pathology refers to applying deep learning techniques and algorithms to analyse and interpret histopathology images. Advances in artificial intelligence (AI) have led to an explosion in innovation in computational pathology, ranging from the prospect of automation of routine diagnostic tasks to the discovery of new prognostic and predictive biomarkers from tissue morphology. Despite the promising potential of computational pathology, its integration in clinical settings has been limited by a range of obstacles including operational, technical, regulatory, ethical, financial, and cultural challenges. Here, we focus on the pathologists' perspective of computational pathology: we map its current translational research landscape, evaluate its clinical utility, and address the more common challenges slowing clinical adoption and implementation. We conclude by describing contemporary approaches to drive forward these techniques. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Multiscale deep learning framework captures systemic immune features in lymph nodes predictive of triple negative breast cancer outcome in large-scale studies.

The suggestion that the systemic immune response in lymph nodes (LNs) conveys prognostic value for triple-negative breast cancer (TNBC) patients has not previously been investigated in large cohorts. We used a deep learning (DL) framework to quantify morphological features in haematoxylin and eosin-stained LNs on digitised whole slide images. From 345 breast cancer patients, 5,228 axillary LNs, cancer-free and involved, were assessed. Generalisable multiscale DL frameworks were developed to capture and quantify germinal centres (GCs) and sinuses. Cox regression proportional hazard models tested the association between smuLymphNet-captured GC and sinus quantifications and distant metastasis-free survival (DMFS). smuLymphNet achieved a Dice coefficient of 0.86 and 0.74 for capturing GCs and sinuses, respectively, and was comparable to an interpathologist Dice coefficient of 0.66 (GC) and 0.60 (sinus). smuLymphNet-captured sinuses were increased in LNs harbouring GCs (p < 0.001). smuLymphNet-captured GCs retained clinical relevance in LN-positive TNBC patients whose cancer-free LNs had on average ≥2 GCs, had longer DMFS (hazard ratio [HR] = 0.28, p = 0.02) and extended GCs' prognostic value to LN-negative TNBC patients (HR = 0.14, p = 0.002). Enlarged smuLymphNet-captured sinuses in involved LNs were associated with superior DMFS in LN-positive TNBC patients in a cohort from Guy's Hospital (multivariate HR = 0.39, p = 0.039) and with distant recurrence-free survival in 95 LN-positive TNBC patients of the Dutch-N4plus trial (HR = 0.44, p = 0.024). Heuristic scoring of subcapsular sinuses in LNs of LN-positive Tianjin TNBC patients (n = 85) cross-validated the association of enlarged sinuses with shorter DMFS (involved LNs: HR = 0.33, p = 0.029 and cancer-free LNs: HR = 0.21 p = 0.01). Morphological LN features reflective of cancer-associated responses are robustly quantifiable by smuLymphNet. Our findings further strengthen the value of assessment of LN properties beyond the detection of metastatic deposits for prognostication of TNBC patients. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Does BRAF mutation status and related clinicopathological factors affect the recurrence rate of ameloblastoma? A systematic review, meta-analysis and metaregression.

OBJECTIVES: This review aims to analyse the recurrence rate in BRAFv600e+ and BRAFv600e- ameloblastomas and explore its association with clinicopathological variables. METHODS: A comprehensive search was conducted using databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, Google Scholar and grey literature, without any limitation on start date or language up to 20 June 2023. A random effect meta-analysis was conducted and Metaregression analyses were performed based on available clinicopathological factors. RESULTS: Fifteen studies met the criteria for meta-analysis of outcomes. There was no significant difference in overall recurrence rates between the two groups (risk difference = 0.001, p-value = 0.987). Increasing male:female ratio in the BRAFv600e+ group was associated with a lower reported recurrence, suggesting a higher recurrence rate in females. The odds of having mandibular lesion were four times higher in BRAFv600e+ cases compared to BRAFv600e- cases (confidence interval: 2.121-7.870, p < 0.001, I2 = 28.37%). CONCLUSION: Within the BRAFv600e+ group, females showed a higher reported recurrence rate. This specific clinical group may benefit from BRAFv600e mutation investigation and potential upscaled surgical treatment and additional BRAF inhibitor therapy, which needs validation in future studies.

Clinical outcomes in relapsed oropharyngeal cancer after definitive (chemo) radiotherapy.

OBJECTIVES: To report clinical outcomes of relapsed oropharyngeal squamous cell carcinoma (OPSCC) after definitive intensity-modulated (chemo)radiotherapy [(C)RT]. MATERIALS AND METHODS: Data for all relapsed patients treated for OPSCC with definitive (C)RT between 2010 and 2016 were collected. Primary end-point was post-failure survival (PFS). RESULTS: Overall, 273 OPSCC patients completed definitive (C)RT. Of these, 42 cases (n = 26 human papilloma virus (HPV)-negative; n = 16 HPV-positive) had relapsed (n = 23 persistent disease; n = 19 recurrent disease) and were included in the final analysis. Two-year PFS for the entire population was 30.6%; 20.5% for HPV-negative and 43.8% for HPV-positive patients. Salvage curative surgery was associated with a significantly higher 2 years PFS rate (56.2%) compared with palliative treatment (22.9%) and best supportive care (0%) (p < 0.001). A positive trend in 2 years PFS was recorded in the early complete response cases (49.5%) versus patients who did not achieve a complete response within 3 months of the end of (C)RT (23.0%) (p = 0.11). CONCLUSION: A higher PFS rate is achieved when relapsed OPSCC cases are treated with salvage curative intent. HPV-positive disease and early complete response within 3 months from the end of (C)RT may be related to better PFS.

Adenoid ameloblastoma harbors beta-catenin mutations.

Adenoid ameloblastoma is a very rare benign epithelial odontogenic tumor characterized microscopically by epithelium resembling conventional ameloblastoma, with additional duct-like structures, epithelial whorls, and cribriform architecture. Dentinoid deposits, clusters of clear cells, and ghost-cell keratinization may also be present. These tumors do not harbor BRAF or KRAS mutations and their molecular basis appears distinct from conventional ameloblastoma but remains unknown. We assessed CTNNB1 (beta-catenin) exon 3 mutations in a cohort of 11 samples of adenoid ameloblastomas from 9 patients. Two of the 9 patients were female and 7 male and in 7/9 patients the tumors occurred in the maxilla. Tumors of 4 of these 9 patients harbored CTNNB1 mutations, specifically p.Ser33Cys, p.Gly34Arg, and p.Ser37Phe. Notably, for one patient 3 samples were analyzed including the primary tumour and two consecutive recurrences, and results were positive for the mutation in all three tumors. Therefore, 6/11 samples tested positive for the mutation. In the 6 mutation-positive samples, ghost cells were present in only 2/6, indicating beta-catenin mutations are not always revealed by ghost cell formation. Dentinoid matrix deposition was observed in 5/6 mutation-positive samples and clear cells in all 6 cases. None of the cases harbored either BRAF or KRAS mutations. Beta-catenin immunoexpression was assessed in the samples of 8 patients. Except for one wild-type case, all cases showed focal nuclear expression irrespective of the mutational status. Together with the absence of BRAF mutation, the detection of beta-catenin mutation in adenoid ameloblastomas supports its classification as a separate entity, and not as a subtype of ameloblastoma. The presence of this mutation may help in the diagnosis of challenging cases.

Centralised pathology service for sentinel node biopsy in oral cavity cancer: The Southeast England Consortium experience.

BACKGROUND: Sentinel lymph node biopsy is an increasingly recognised option for accurate staging and subsequent management of the clinically negative neck in early stage oral cavity squamous cell carcinoma. However, the technique is currently underused due to several logistic constraints including increased burden on pathology services. Here, we describe the feasibility of an outsourced centralised pathology processing and reporting service for sentinel lymph node biopsies in oral cavity squamous cell carcinoma. PATIENTS AND METHODS: The Southeast England Consortium comprises four surgical centres utilising a central pathology service. Consecutive cases between January 2016 and February 2020 were retrospectively evaluated for survival outcomes and laboratory turnaround times. RESULTS: Twenty-eight per cent from a cohort of 139 patients had positive sentinel nodes. There was a trend towards greater overall, disease-free and disease-specific survival (OS, DFS and DSS, respectively) in sentinel node negative compared to sentinel node positive patients, but these differences were not statistically significant. The sensitivity, negative predictive value and false negative rate were 92.8%, 97.0% and 6.8%, respectively. The mean and mode laboratory TAT were 5 and 4 working days, respectively. CONCLUSION: An outsourced centralised pathology service is a feasible option to widen the availability of sentinel node biopsy in oral cavity squamous cell carcinoma.

Candidalysin is a fungal peptide toxin critical for mucosal infection.

Cytolytic proteins and peptide toxins are classical virulence factors of several bacterial pathogens which disrupt epithelial barrier function, damage cells and activate or modulate host immune responses. Such toxins have not been identified previously in human pathogenic fungi. Here we identify the first, to our knowledge, fungal cytolytic peptide toxin in the opportunistic pathogen Candida albicans. This secreted toxin directly damages epithelial membranes, triggers a danger response signalling pathway and activates epithelial immunity. Membrane permeabilization is enhanced by a positive charge at the carboxy terminus of the peptide, which triggers an inward current concomitant with calcium influx. C. albicans strains lacking this toxin do not activate or damage epithelial cells and are avirulent in animal models of mucosal infection. We propose the name 'Candidalysin' for this cytolytic peptide toxin; a newly identified, critical molecular determinant of epithelial damage and host recognition of the clinically important fungus, C. albicans.

RNA in situ hybridization for human papillomavirus testing in oropharyngeal squamous cell carcinoma on a routine clinical diagnostic platform.

BACKGROUND: The current diagnostic standard for detection of high-risk human papillomavirus (HPV) in oropharyngeal squamous cell carcinoma is via a two-stage algorithm, namely p16 immunohistochemistry followed by HPV DNA in situ hybridization in p16 positive cases. This study evaluated the feasibility of automated RNA in situ hybridization on a clinical platform as a single-step alternative to the two-stage algorithm within a routine diagnostic histopathology setting. METHODS: Thirty-eight cases positive for both p16 and DNA in situ hybridization, 42 p16 negative cases and 20 cases positive for p16 but negative for DNA in situ hybridization were randomly selected. High-risk HPV RNA in situ hybridization was undertaken on all cases on an automated clinical platform. Manufacturer-recommended and on-slide additional p16/HPV positive and negative controls were used. Test quality assurance and diagnostic RNA in situ hybridization were independently assessed by two observers. A consensus diagnosis was reached in the presence of a third observer on discordant cases. All RNA in situ hybridization results were then correlated against p16 and DNA ISH status. RESULTS: Inter-slide RNA in situ hybridization staining variation was observed in control sections. RNA in situ hybridization demonstrated a high inter-observer agreement rate (κ = .897, P < .001). Following consensus review, there was full concordance between RNA in situ hybridization and the current standard. CONCLUSION: Human papillomavirus testing by standalone automated RNA in situ hybridization on a clinical diagnostic platform currently available in routine diagnostic histopathology laboratories is a feasible alternative to the two-step algorithm of p16 and DNA in situ hybridization. Control tissue staining procedures need to be adapted to achieve the most accurate results.

MAPK pathway control of stem cell proliferation and differentiation in the embryonic pituitary provides insights into the pathogenesis of papillary craniopharyngioma.

Despite the importance of the RAS-RAF-MAPK pathway in normal physiology and disease of numerous organs, its role during pituitary development and tumourigenesis remains largely unknown. Here, we show that the over-activation of the MAPK pathway, through conditional expression of the gain-of-function alleles BrafV600E and KrasG12D in the developing mouse pituitary, results in severe hyperplasia and abnormal morphogenesis of the gland by the end of gestation. Cell-lineage commitment and terminal differentiation are disrupted, leading to a significant reduction in numbers of most of the hormone-producing cells before birth, with the exception of corticotrophs. Of note, Sox2+ stem cells and clonogenic potential are drastically increased in the mutant pituitaries. Finally, we reveal that papillary craniopharyngioma (PCP), a benign human pituitary tumour harbouring BRAF p.V600E also contains Sox2+ cells with sustained proliferative capacity and disrupted pituitary differentiation. Together, our data demonstrate a crucial function of the MAPK pathway in controlling the balance between proliferation and differentiation of Sox2+ cells and suggest that persistent proliferative capacity of Sox2+ cells may underlie the pathogenesis of PCP.

The impact of intensity-modulated radiation treatment on dento-alveolar microvasculature in pharyngeal cancer implant patients.

OBJECTIVES: Dental rehabilitation post-radiotherapy often requires the consideration of dental implants. However, these are tentatively prescribed due to the concern of hypovascularisation and possible osteoradionecrosis. Hence, the current study assessed the microvasculature of the dento-alveolar bone at implant sites taking into consideration the exact radiotherapy dose received to the region. MATERIALS AND METHODS: Bone cores were taken from nine patients during implant treatment and compared to nine control patients. Specimens were stained using CD31 and digitalised using a high-resolution scanner for qualitative and quantitative assessment of the microvasculature. Monaco® treatment planning system was used to volume the implant site providing mean dose (Dmean ) and maximum dose (Dmax ). RESULTS: A total of 23 bone cores were retrieved for analysis. The cohort had a Dmean of 38.4 Gy (59.6-24.3 Gy). Qualitative analysis identified a clear reduction in the miniscule terminal capillaries and high incidence of obliterated lumens with increasing radiotherapy. Microvasculature density of irradiated patients was markedly reduced (P = .0034) compared to the control group with an inverse correlation to RT doses (P < .0001). Specifically, doses up to 30 Gy appear to preserve sufficient vascularisation (~77% in comparison with control) and tissue architecture. By contrast, exposure to higher doses 40%-61% of the micro-vessels were lost. CONCLUSION: Intensity-modulated radiotherapy doses above 30 Gy identified reduction in microvasculature which is a lower threshold than previously accepted. In pharyngeal cancer patients' doses to the jaw bones often exceed this threshold. Coupled with favourable survival in certain oropharyngeal and nasopharyngeal cancer, dental rehabilitation via implants provides a significant clinical challenge.

Clinical evaluation of tumour-infiltrating lymphocytes as a prognostic factor in patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma.

Clinical evaluation of tumour-infiltrating lymphocytes as a prognostic factor in patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma AIMS: The majority of patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OpSCC) have favourable survival outcomes, but a significant minority of individuals will die of their disease. There are currently no definitive criteria with which to identify HPV-associated OpSCC patients with poor outcomes. Recent reports suggest that quantitative evaluation of T-cell subpopulations in OpSCC may be of prognostic value, but the methods used have limited utility in a clinical diagnostic setting. We therefore sought to determine the clinical prognostic utility of tumour-infiltrating lymphocyte (TIL) evaluation in patients with HPV-associated OpSCC within the context of a diagnostic histopathology setting. METHODS AND RESULTS: Representative diagnostic haematoxylin and eosin (H&E)-stained slides from 232 consecutive HPV-associated OpSCC patients were classified as containing a high (TILHi ; diffuse, lymphocytes in >80% of tumour and stroma), moderate (TILMod ; patchy, present in 20-80% of tumour and stroma) or low (TILLo ; sparse or absent, present in <20% of tumour and stroma) TILs. Interobserver reliability was assessed, and TIL category was then correlated with overall survival (OS) and disease-free survival (DFS). Univariate and multivariate analyses showed statistically significant differences in OS and DFS estimates when TILHi and TILMod patients were compared with TILLo patients (P < 0.0001 for TILHi versus TILLo ; P < 0.0001 for TILMod versus TILLo ). Statistical significance was retained when TILHi and TILMod patients were grouped into a single category (TILHi ) and compared with TILLo patients (P < 0.0001). CONCLUSION: We demonstrate the prognostic utility of TILs in patients with HPV-associated OpSCC in clinical practice. A binary system classifying HPV-associated OpSCC into TILHi and TILLo on the basis of routine H&E staining stratifies patients into those with potentially favourable and unfavourable survival outcomes, respectively.

Tumour compartment transcriptomics demonstrates the activation of inflammatory and odontogenic programmes in human adamantinomatous craniopharyngioma and identifies the MAPK/ERK pathway as a novel therapeutic target.

Adamantinomatous craniopharyngiomas (ACPs) are clinically challenging tumours, the majority of which have activating mutations in CTNNB1. They are histologically complex, showing cystic and solid components, the latter comprised of different morphological cell types (e.g. ß-catenin-accumulating cluster cells and palisading epithelium), surrounded by a florid glial reaction with immune cells. Here, we have carried out RNA sequencing on 18 ACP samples and integrated these data with an existing ACP transcriptomic dataset. No studies so far have examined the patterns of gene expression within the different cellular compartments of the tumour. To achieve this goal, we have combined laser capture microdissection with computational analyses to reveal groups of genes that are associated with either epithelial tumour cells (clusters and palisading epithelium), glial tissue or immune infiltrate. We use these human ACP molecular signatures and RNA-Seq data from two ACP mouse models to reveal that cell clusters are molecularly analogous to the enamel knot, a critical signalling centre controlling normal tooth morphogenesis. Supporting this finding, we show that human cluster cells express high levels of several members of the FGF, TGFB and BMP families of secreted factors, which signal to neighbouring cells as evidenced by immunostaining against the phosphorylated proteins pERK1/2, pSMAD3 and pSMAD1/5/9 in both human and mouse ACP. We reveal that inhibiting the MAPK/ERK pathway with trametinib, a clinically approved MEK inhibitor, results in reduced proliferation and increased apoptosis in explant cultures of human and mouse ACP. Finally, we analyse a prominent molecular signature in the glial reactive tissue to characterise the inflammatory microenvironment and uncover the activation of inflammasomes in human ACP. We validate these results by immunostaining against immune cell markers, cytokine ELISA and proteome analysis in both solid tumour and cystic fluid from ACP patients. Our data support a new molecular paradigm for understanding ACP tumorigenesis as an aberrant mimic of natural tooth development and opens new therapeutic opportunities by revealing the activation of the MAPK/ERK and inflammasome pathways in human ACP.

(18)F-FDG PET/CT to assess response and guide risk-stratified follow-up after chemoradiotherapy for oropharyngeal squamous cell carcinoma.

PURPOSE: To evaluate the use of (18)F-FDG PET/CT as the principal investigation to assess tumour response, to determine the need for further surgery and to guide follow-up following radical chemoradiotherapy for stage III/IV oropharyngeal squamous cell carcinoma (OPSCC). METHODS: A retrospective analysis was undertaken in 146 patients treated at our centre with radical chemoradiotherapy for OPSCC and who had a PET/CT scan to assess response. According to the PET/CT findings, patients were divided into four groups and recommendations: (1) complete metabolic response (enter clinical follow-up); (2) low-level uptake only (follow-up PET/CT scan in 12 weeks); (3) residual uptake suspicious for residual disease (further investigation with or without neck dissection); and (4) new diagnosis of distant metastatic disease (palliative treatment options). RESULTS: The initial PET/CT scan was performed at a median of 12.4 weeks (range 4.3 - 21.7 weeks) following treatment. Overall sensitivity and specificity rates were 92.0 % (74.0 - 99.0 %) and 85 % (77.5 - 90.9 %). Of the 146 patients, 90 (62 %) had a complete response and had estimated 3-year overall and disease-free survival rates of 91.9 % (85.6 - 98.2 %) and 85.6 % (78.0 - 93.2 %), respectively, 17 (12 %) had residual low-level uptake only (with two having confirmed residual disease on subsequent PET/CT, both surgically salvaged), 30 (21 %) had suspicious residual uptake (12 proceeded to neck dissection; true positive rate at surgery 33 %). HPV-positive patients with reassuring PET/CT findings had an estimated 3-year progression-free survival rate of 91.7 % (85.2 - 98.2 %), compared with 66.2 % (41.5 - 90.9 %) of HPV-negative patients. CONCLUSION: A strategy of using PET/CT results alongside clinical examination to help select patients for salvage surgery appears successful. Despite a complete response on the 12-week PET/CT scan, HPV-negative patients have a significant risk of disease relapse in the following 2 years and further studies to assess whether surveillance imaging in this group could improve outcomes are warranted.

Down-regulation of LPA receptor 5 contributes to aberrant LPA signalling in EBV-associated nasopharyngeal carcinoma.

Undifferentiated nasopharyngeal carcinoma (NPC) is a highly metastatic disease that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we have investigated the contribution of lysophosphatidic acid (LPA) signalling to the pathogenesis of NPC. Here we demonstrate two distinct functional roles for LPA in NPC. First, we show that LPA enhances the migration of NPC cells and second, that it can inhibit the activity of EBV-specific cytotoxic T cells. Focusing on the first of these phenotypes, we show that one of the LPA receptors, LPA receptor 5 (LPAR5), is down-regulated in primary NPC tissues and that this down-regulation promotes the LPA-induced migration of NPC cell lines. Furthermore, we found that EBV infection or ectopic expression of the EBV-encoded LMP2A was sufficient to down-regulate LPAR5 in NPC cell lines. Our data point to a central role for EBV in mediating the oncogenic effects of LPA in NPC and identify LPA signalling as a potential therapeutic target in this disease.

Human papillomavirus-associated neoplasms of the sinonasal tract and nasopharynx.

It is now well established that human papillomavirus (HPV) is an important causative factor in a subgroup of head and neck cancer. In the head and neck, while HPV is strongly associated with squamous cell carcinoma arising in the oropharynx, there is a growing interest in HPV-associated neoplasms of non-oropharyngeal origin including those which arise within sinonasal and nasopharyngeal mucosa. This article reviews current literature on the association of HPV with Scheiderian papillomas, sinonasal squamous cell carcinoma, sinonasal undifferentiated carcinoma, carcinoma with adenoid cystic-like features, and nasopharyngeal carcinoma. Several clinical implications of HPV detection in sinonasal and nasopharyngeal carcinomas are briefly discussed.

Quantification of lymph nodes in the central compartment of the neck: a cadaveric study.

Differentiated thyroid cancer (DTC) accounts for over 90 % of thyroid malignancies, and is frequently associated with central neck compartment nodal metastasis that requires a therapeutic central compartment neck dissection (CCND) for clinically evident nodes. Current knowledge on the expected lymph node yield from a CCND is limited, compared with data on the lateral neck. The aim of our study was to accurately quantify nodal yield from the cadaveric central neck compartment. Twenty-eight cadaveric necks were dissected and the central neck compartment was subdivided into four regions: pre-laryngeal (delphian), pre-tracheal, right and left para-tracheal regions. Each cadaver had a thyroid gland, which was also removed, and the CCND tissue in each compartment was processed and examined by a consultant histopathologist. Only lymphoid tissue with a defined microscopic fibrous capsule and subcapsular sinus was included in the node count. The median total lymph node count per cadaver was four (range 1-16), with a median of one node detectable in each para-tracheal region (range 0-7) and the pre-tracheal region (range 0-8). The median pre-laryngeal node count was 0 (range 0- 2). The average lymph node size across all compartments was 2.9 mm. This is the first European study to assess cadaveric central neck lymph nodes and establish baseline counts for nodal yield. If a prophylactic or therapeutic CCND is required during thyroid surgery, those involved in DTC management must recognise that there is a wide range, and low median yield of central neck compartment lymph nodes.

Dermatophytes activate skin keratinocytes via mitogen-activated protein kinase signaling and induce immune responses.

Dermatophytes cause superficial and cutaneous fungal infections in immunocompetent hosts and invasive disease in immunocompromised hosts. However, the host mechanisms that regulate innate immune responses against these fungi are largely unknown. Here, we utilized commercially available epidermal tissues and primary keratinocytes to assess (i) damage induction by anthropophilic, geophilic, and zoophilic dermatophyte strains and (ii) the keratinocyte signaling pathways, transcription factors, and proinflammatory responses induced by a representative dermatophyte, Trichophyton equinum. Initially, five dermatophyte species were tested for their ability to invade, cause tissue damage, and induce cytokines, with Microsporum gypseum inducing the greatest level of damage and cytokine release. Using T. equinum as a representative dermatophyte, we found that the mitogen-activated protein kinase (MAPK) pathways were predominantly affected, with increased levels of phospho-p38 and phospho-Jun N-terminal protein kinase (JNK) but decreased levels of phospho-extracellular signal-regulated kinases 1 and 2 (ERK1/2). Notably, the NF-κB and PI3K pathways were largely unaffected. T. equinum also significantly increased expression of the AP-1-associated transcription factor, c-Fos, and the MAPK regulatory phosphatase, MKP1. Importantly, the ability of T. equinum to invade, cause tissue damage, activate signaling and transcription factors, and induce proinflammatory responses correlated with germination, indicating that germination may be important for dermatophyte virulence and host immune activation.

Incidental Thyroid Tissue in Sentinel Nodes From Oral Squamous Cell Carcinoma.

OBJECTIVE: Sentinel node biopsy (SNB) is a surgical staging test in which sentinel nodes (SNs) undergo intensive histological analysis. SNB diagnoses early cancer spread, but can also reveal unexpected findings within the SNs. We review cases of incidental thyroid cells (TC) found in SNs from patients with oral squamous cell carcinoma (OSCC) to assess the prevalence of TC, and the clinical significance of these. METHODS: Multicenter retrospective review of SNB performed for cT1-T2N0 OSCC. Incidental TC were identified by TTF-1 or thyroglobulin positivity. Anatomical location of nodes containing TC, TC morphology, and ongoing management/follow up of this incidental finding was recorded. Neck dissections performed during the same period were reviewed to establish the expected incidence of TC in neck nodes without serial sectioning analysis. RESULTS: 278 SNB cases were reviewed. Ten procedures detected TC in nine patients (10/278, 3.6%). During the same time period 725 neck dissections were performed, six containing TCs (6/725, 0.8%). One patient underwent SNB twice with TC identified on both occasions. Three patients had both OSCC metastasis and thyroid cells. All SNB patients with TC identified underwent thyroid USS with no primary tumours identified. Three patients underwent thyroidectomy, in all cases no primary thyroid tumour was found. CONCLUSION: Prevalence of incidental TC in SNs appears to be higher than that reported in neck dissections, these are not likely to be clinically relevant and can be managed on a conservative basis in the absence of clear metastatic features. LEVEL OF EVIDENCE: Multicentre retrospective cohort study, 3 Laryngoscope, 134:1278-1281, 2024.