Lichenoid dysplasia is not a distinct pathological entity

Autoimmunity and epithelial dysplasia in patients with oral lichenoid diseases

OBJECTIVES

The primary objective of this study was to explore relationship between autoimmunity and epithelial dysplasia in patients with oral lichenoid diseases.

MATERIALS AND METHODS

A total of 66 patients with oral lichen planus (OLP), 35 with oral lichenoid lesion (OLL), and 85 with oral lichenoid drug reaction (OLDR) were enrolled. OLP, OLL, and OLDR were diagnosed following the definitions of the modified World Health Organization criteria, except for the absence of epithelial dysplasia. All patients underwent diagnostic incisional biopsy and adjunctive direct immunofluorescence assays. An indirect immunofluorescence assay was conducted to determine the antinuclear antibody (ANA) positivity.

RESULTS

OLP and OLDR patients with epithelial dysplasia demonstrated higher prevalence of serum ANA positivity compared to those without epithelial dysplasia. Elevated serum levels of high sensitivity-C reactive proteins were observed in the OLP, OLL, and OLDR patients with epithelial dysplasia. In the DIF analysis, patients with epithelial dysplasia in the OLP exhibited a higher prevalence of C3 deposition in the basement membrane zone.

CONCLUSIONS

This study proposed that autoimmunity may contribute to elevating levels of focal and chronic systemic inflammation, potentially influencing abnormal wound healing and development of dysplastic changes in the oral epithelium among patients with oral lichenoid disease.

Global gene expression profile of proliferative verrucous leukoplakia and its underlying biological disease mechanisms

BACKGROUND

Proliferative verrucous leukoplakia (PVL) is a rare and enigmatic oral potentially malignant disorder which almost invariably results in oral squamous cell carcinoma (OSCC). The aims of this project were to use transcriptome profiling to characterise PVL gene expression patterns for biomarker identification and gain insight into the molecular aetiopathogenesis of PVL.

METHODS

Forty-three oral cavity mucosal biopsies from 32 patients with oral lesions clinically compatible with either PVL or non-PVL conventional oral leukoplakia (OLK) underwent transcriptome profiling by RNA sequencing. Data was analysed by hierarchical clustering, differential gene expression, functional enrichment and network analysis, sparse partial least squares discriminant analysis sPLS-DA, and immune cell phenotypic estimation.

RESULTS

We found 464 genes significantly differentially expressed at least 2-fold between PVL and non-PVL OLK (193 up and 271 down). HOX genes, including HOXA1 and HOXB7, keratin-associated proteins (KRTAPs) and olfactory receptor G proteins (OR) were significantly upregulated in PVL. Other upregulated genes in PVL included FOS, WNT16 and IFNA1. Pathway analysis showed that there was a significant downregulation of connective tissue signalling in PVL. Classifying multivariate models based upon 22 genes discriminated PVL from non-PVL OLK. Bioinformatic profiling showed that immune cell profiles in PVL and OLK were similar except that fibroblast markers were reduced in PVL.

CONCLUSION

These results demonstrate that PVL and conventional OLK are molecularly distinct with upregulation of many cancer-associated genes. They provide insight into the pathogenesis of PVL and show that biomarker based molecular diagnostics is feasible to discriminate and inform diagnosis and management.

Podoplanin could be a predictive biomarker of the risk of patients with oral leukoplakia to develop oral cancer: A systematic review and meta-analysis

OBJECTIVES

The aim of this study is to identify and analyze the existing literature on the utility of podoplanin to predict the risk of malignancy development (MD) in patients previously diagnosed with oral leukoplakia (OL).

METHODS

A systematic review and meta-analysis (SRMA) was performed though a search strategy using several electronic databases and a combination of keywords related to podoplanin and MD of OL, until 15 May, 2022 (PROSPERO CRD42022329326). Evaluation of the risk of bias (ROB) was performed using the Quality in Prognosis Studies Tool. The meta-analyses were estimated using fixed-effect models.

RESULTS

From 421 articles, 6 studies were finally included, that enrolled 546 patients with OL, of whom 125 presented with an oral cancer during follow-up (32 to 90 months). Some limitations regarding the ROB were identified mostly related to small sample sizes, short follow-up times, lack of information on covariables in the included studies and lack of accuracy (including sensitivity and specificity). Meta-analysis of 6 studies reveal that high expression of podoplanin carries a pooled hazard ratio (HR) of 3.72 (95% CI, 2.40-5.76; p < 0.00001) for MD without statistical heterogeneity (I2  = 0%, p = 0.53).

CONCLUSION

The results of this SRMA support the role of podoplanin immunohistochemical expression as a potential predictive biomarker to assess the risk of malignancy development in oral leukoplakia.

Demystifying oral epithelial dysplasia: a histological guide

Oral epithelial dysplasia is a histologically diagnosed potentially premalignant disorder of the oral mucosa, which carries a risk of malignant transformation to squamous cell carcinoma. The diagnosis and grading of oral epithelial dysplasia is challenging, with cases often referred to specialist oral and maxillofacial pathology centres for second opinion. Even still there is poor inter-examiner and intra-examiner agreement in a diagnosis. There are a total of 28 features of oral epithelial dysplasia listed in the 5th edition of World Health Organization classification of tumours of the head and neck. Each of these features is poorly defined and subjective in its interpretation. Moreover, how these features contribute to dysplasia grading and risk stratification is even less well defined. This article discusses each of the features of oral epithelial dysplasia with examples and provides an overview of the common mimics, including the normal histological features of the oral mucosa which may mimic atypia. This article also highlights the paucity of evidence defining these features while offering suggested definitions. Ideally, these definitions will be refined, and the most important features identified to simplify the diagnosis of oral epithelial dysplasia. Digital whole slide images of the figures in this paper can be found at: https://www.pathogenesis.co.uk/r/demystifying-dysplasia-histology-dataset.

Direct immunofluorescence cannot be used solely to differentiate among oral lichen planus, oral lichenoid lesion, and oral epithelial dysplasia

Background/purpose

Some red and white lesions may have similar manifestations, making them difficult to be diagnosed. A direct immunofluorescence (DIF) assay can assist in making a final diagnosis of oral lichen planus (OLP). The aim of this study was to evaluate and compare the DIF profile in patients who had the clinical presentations of OLP and were histopathologically diagnosed with OLP, OLL (oral lichenoid lesion), or OED (oral epithelial dysplasia).

Materials and methods

The data were obtained from the medical records of 136 patients with the clinical presentations of OLP. Demographic information, histopathological diagnosis, malignant transformation, and DIF results were collected and analyzed.

Results

In this study, 117 patients (86.0%) were DIF-positive, while 19 patients (14.0%) were DIF-negative. The highest DIF-positivity rate was in the OLP group (88.9%) followed by the OLL (83.7%), and the OED groups (81%). There were no significant differences in DIF-positivity rate, type of immunoreactants, location, or interpretation among these groups. Shaggy fibrinogen at the basement membrane zone (BMZ) was the most common DIF pattern in all groups.

Conclusion

The DIF assay alone cannot be regarded as sufficient evidence for OLP, OLL, and OED differentiation. A histopathological examination is required to determine the presence of epithelial dysplasia or malignancy. To diagnose dysplastic lesions with the clinical manifestations of OLP, careful clinicopathologic correlation is mandatory. Due to the lack of scientific evidence to identify the primary pathology and the ongoing malignancy risk of epithelial dysplasia, meticulous long-term follow-up plays a crucial role in patient management.

Rate of Malignant Transformation Differs Based on Diagnostic Criteria for Oral Lichenoid Conditions: A Systematic Review and Meta-Analysis of 24,277 Patients

OBJECTIVES

This systematic review and meta-analysis aims to evaluate the evidence on the malignant potential of oral lichenoid conditions (OLCs) including oral lichen planus (OLP), oral lichenoid lesions (OLL), and lichenoid mucositis dysplasia (LMD). In addition, it aims to compare the rate of malignant transformation (MT) in OLP patients diagnosed according to different diagnostic criteria, and to investigate the possible risk factors for OLP MT into OSCC.

MATERIALS AND METHODS

A standardized search strategy was applied across four databases (PubMed, Embase, Web of Science, and Scopus). Screening, identification and reporting followed the PRISMA framework. Data on MT were calculated as a pooled proportion (PP), subgroup analyses and possible risk factors for MT were pooled as odds ratios (ORs).

RESULTS

Among 54 studies with 24,277 patients, the PP for OLCs MT was 1.07% (95% CI [0.82, 1.32]). The estimated MT rate for OLP, OLL and LMD was 0.94%, 1.95% and 6.31%, respectively. The PP OLP MT rate using the 2003 modified WHO criteria group was lower than that using the non-2003 criteria (0.86%; 95% CI [0.51, 1.22] versus 1.01%; 95% CI [0.67, 1.35]). A higher odds ratio of MT was observed for red OLP lesions (OR = 3.52; 95% CI [2.20, 5.64]), smokers (OR = 1.79; 95% CI [1.02, 3.03]), alcohol consumers (OR = 3.27, 95% CI [1.11, 9.64]) and those infected with HCV (OR = 2.55, 95% CI [1.58, 4.13]), compared to those without these risk factors.

CONCLUSIONS

OLP and OLL carry a low risk of developing OSCC. MT rates differed based on diagnostic criteria. A higher odds ratio of MT was observed among red OLP lesions, smokers, alcohol consumers, and HCV-positive patients. These findings have implications for practice and policies.

Oral cavity carcinoma in patients with and without a history of lichen planus: A comparative analysis

BACKGROUND

Oral potentially malignant disorders (OPMD) are associated with the risk of malignant transformation (MT) into oral cavity carcinoma (OCC). Oral lichen planus (OLP) is one of the most common OPMDs in western countries. Although there is a substantial amount of research on progression to cancer, a specific analysis of the clinical characteristics and prognosis of cancer developed in patients with a history of OLP versus patients without a history of OLP has not been investigated so far.

METHODS

Retrospective evaluation of 82 patients treated for OCC with a known history of OLP compared to a representative sample of 82 patients treated for OCC without a known history of LP. Comparative analyses were performed on age at presentation, sex, TNM staging, clinical characteristics, pathology characteristics, 2- and 5-year overall survival (OS), and disease-free survival (DFS).

RESULTS

It was shown that patients with a history of LP were significantly younger at first presentation than patients without a history of LP (mean age difference 6.7 years, 95% CI 3.1-10.3, p < 0.05). Also, patients with a history of OLP were in higher proportion females. The main pathological stage at presentation was significantly lower in the OLP group (p < 0.05). The 2-year survival analysis showed that DFS and OS were significantly lower in patients without a known history of OLP, with a hazard ratio (HR) of 3.1 (95% CI 1.4-6.8) and HR of 2.6 (95% CI 1.3-5.3), respectively. The 5-year survival analysis showed that DFS and OS were significantly lower in patients without a known history of OLP, with a hazard ratio of 3.1 (95% CI 1.6-6.2) and of 2.9 (95% CI 1.5-5.6), respectively.

CONCLUSIONS

Cancer arising from OLP has peculiar characteristics compared to cancer in naïve patients. It most commonly affects younger patients, women, and nonsmokers. It is usually diagnosed at earlier stages and appears to have less aggressive behavior at presentation. Moreover, when 2- and 5-year survival is analyzed, it appears that patients in OLP group have an overall and a disease-free survival advantage. These results suggest that cancer from OLP is less aggressive and thus has a potential biological difference with cancer arising in non-OLP patients. Further clinical and basic investigations are needed to confirm the results of this study.

Oral Lichen Planus and Oral Squamous Cell Carcinoma share key oncogenic signatures

To investigate similarities in the gene profile of Oral Lichen Planus and Oral Squamous Cell Carcinoma that may justify a carcinogenic potential, we analyzed the gene expression signatures of Oral Lichen Planus and Oral Squamous Cell Carcinoma in early and advanced stages. Based on gene expression data from public databases, we used a bioinformatics approach to compare expression profiles, estimate immune infiltrate composition, identify differentially and co-expressed genes, and propose putative therapeutic targets and associated drugs. Our results revealed gene expression patterns related to processes of keratinization, keratinocyte differentiation, cell proliferation and immune response in common between Oral Lichen Planus and early and advanced Oral Squamous Cell Carcinoma, with the cornified envelope formation and antigen processing cross-presentation pathways in common between Oral Lichen Planus and early Oral Squamous Cell Carcinoma. Together, these results reveal that key tumor suppressors and oncogenes such as PI3, SPRR1B and KRT17, as well as genes associated with different immune processes such as CXCL13, HIF1A and IL1B are dysregulated in OLP.

Immunoexpression of oral brush biopsy enhances the accuracy of diagnosis for oral lichen planus and lichenoid lesions

Background

This study assessed the efficacy of using oral liquid‐based brush cytology (OLBC) coupled with immunostained cytology‐derived cell‐blocks, quantified using machine‐learning, in the diagnosis of oral lichen planus (OLP).

Methods

Eighty‐two patients diagnosed clinically with either OLP or oral lichenoid lesion (OLL) were included. OLBC samples were obtained from all patients before undergoing surgical biopsy. Liquid‐based cytology slides and cell‐blocks were prepared and assessed by cytomorphology and immunocytochemistry for four antibodies (Ki‐67, BAX, NF‐κB‐p65, and AMACR). For comparison purposes, a sub‐group of 31 matched surgical biopsy samples were selected randomly and assessed by immunohistochemistry. Patients were categorized according to their definitive diagnoses into OLP, OLL, and clinically lichenoid, but histopathologically dysplastic lesions (OEDL). Machine‐learning was utilized to provide automated quantification of positively stained protein expression.

Results

Cytomorphological assessment was associated with an accuracy of 77.27% in the distinction between OLP/OLL and OEDL. A strong concordance of 92.5% (κ = 0.84) of immunostaining patterns was evident between cell‐blocks and tissue sections using machine‐learning. A diagnostic index using a Ki‐67‐based model was 100% accurate in detecting lichenoid cases with epithelial dysplasia. A BAX‐based model demonstrated an accuracy of 92.16%. The accuracy of cytomorphological assessment was greatly improved when it was combined with BAX immunoreactivity (95%).

Conclusions

Cell‐blocks prepared from OLBC are reliable and minimally‐invasive alternatives to surgical biopsies to diagnose OLLs with epithelial dysplasia when combined with Ki‐67 immunostaining. Machine‐learning has a promising role in the automated quantification of immunostained protein expression.

TLR4 Expression in Ex-Lichenoid Lesions—Oral Squamous Cell Carcinomas and Its Surrounding Epithelium: The Role of Tumor Inflammatory Microenvironment

Toll-like receptors (TLRs) regulate innate and adaptive immune responses. Moreover, TLRs can induce a pro-survival and pro-proliferation response in tumor cells. This study aims to investigate the expression of TLR4 in the epithelium surrounding oral squamous cell carcinomas (OSCC) in relation to its inflammatory microenvironment. This study included 150 human samples: 30 normal oral control (NOC), 38 non-lichenoid epithelium surrounding OSCC (NLE-OSCC), 28 lichenoid epithelium surrounding OSCC (LE-OSCC), 30 OSCC ex-non oral lichenoid lesion (OSCC Ex-NOLL), and 24 OSCC ex-oral lichenoid lesion (OSCC Ex-OLL). TLR4 expression was investigated by immunohistochemistry and the percentage of positive cells was quantified. In addition, a semiquantitative analysis of staining intensity was performed. Immunohistochemical analysis revealed that TLR4 is strongly upregulated in LE-OSCC as compared to normal control epithelium and NLE-OSCC. TLR4 expression was associated with the inflammatory environment, since the percentage of positive cells increases from NOC and NLE-OSCC to LE-OSCC, reaching the highest value in OSCC Ex–OLL. TLR4 was detected in the basal third of the epithelium in NLE-OSCC, while in LE-OSCC, TLR4 expression reached the intermediate layer. These results demonstrated that an inflammatory microenvironment can upregulate TLR4, which may boost tumor development.

Oral epithelial dysplasia: Recognition, grading and clinical significance

Histopathological grading of epithelial dysplasia remains the principal laboratory method for assessing the risk of malignant transformation in oral potentially malignant disorders (OPMDs). Current views on the molecular pathogenesis and histological interpretation of the features of epithelial dysplasia are described, and the use of grading systems for epithelial dysplasia is discussed. Changes to the current 2017 WHO criteria for diagnosis are proposed with emphasis on the architectural features of epithelial dysplasia. The predictive values of three-grade and binary systems are summarised, and categories of epithelial dysplasia are reviewed, including lichenoid and verrucous lesions, keratosis of unknown significance, HPV-associated dysplasia, differentiated and basaloid epithelial dysplasia. The implications of finding epithelial dysplasia in an oral biopsy for clinical management are discussed from the pathologists' viewpoint.

A machine-learning algorithm for the reliable identification of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a relatively common oral disorder which shares clinical and histopathological features with other lichenoid lesions, leading to considerable inter-observer disagreement. This negatively impacts understanding of the pathogenesis and malignant transformation potential of this condition.

METHODS

Artificial intelligence was employed to create a machine-learning artificial neural network to identify and quantify mononuclear cells and granulocytes within the inflammatory infiltrates in digitized hematoxylin and eosin microscopic slides. Twenty-four regions of interest were extracted from OLP cases for learning purposes and validated on a retrospective cohort of 130 cases. All cases were related to patients with confirmed diagnoses of OLP, oral lichenoid lesions (OLLs), or oral epithelial dysplasia (OED) with lichenoid host response.

RESULTS

The number of inflammatory cells was statistically significantly higher in OLP compared to OLLs or OED with lichenoid host response (p < 0.0005). The proposed machine-learning method was reliably capable of detecting OLP cases based on the number of inflammatory cells and the number of mononuclear cells with an area under the curve of 0.982 and 0.988, respectively. Identifying a cut-off point between OLP and other lichenoid conditions based on the number of mononuclear cells showed a sensitivity of 100% and an accuracy of 94.62%.

CONCLUSION

Artificial intelligence has shown promising outcomes and provides a robust approach to enhance the accuracy of anatomical pathologists in accurately diagnosing OLP using features of disease pathogenesis.