Implications on pathogenesis and risk of oral lichen planus neoplastic transformation: an ex-vivo retrospective immunohistochemical study.

AIMS: To evaluate OPN, MCM7, Ki-67, p53, Bcl-2 and 53BP1 presence, together with the abnormal adaptive CD4 and CD8 T-cell response markers expression in a series of oral lichen planus (OLP) affected patients and assess their combined contribution for a more objective disease classification. METHODS AND RESULTS: In this ex-vivo retrospective analysis, biopsy specimens from 28 adults with a clinical diagnosis of OLP at different progression degree (16 reticular, 2 plaque-like, 1 erosive and 9 mixed type) were collected. Sections were immunohistochemically investigated for the proinflammatory cytokine osteopontin (OPN), alpha-beta CD4 and CD8 positive T cells, DNA replication licensing factor (MCM7), proliferating cell marker (Ki-67), apoptotic and tumor antigen (p53), apoptosis modulator (Bcl-2) and cellular response regulator to double-strand breaks tumor suppressor p53-binding protein 1 expression. Statistical analysis revealed that 53BP1 is highly represented among the OLP study patients (p<0.05). Moreover, on the basis of the quantification results of the highly expressed parameters, two illness categories with different severity were evidenced. The classification hypothesis was confirmed by i) OLP lesion persistence, ii) the development of oral severe lesions in the patients belonging to high grade activity OLP group (HGA-OLPs) and iii) the ascertainment of the same evidence both in the oral squamous cell tumor controls (OSCC) and in HGA-OLP cases. CONCLUSION: This study completes the scenario with respect to early detection, thanks to a more precise histological analysis, for rationalizing the clinical and histological findings toward a sharable international disease scoring system.

Reticular and erosive oral lichen planus have a distinct metabolomic profile: A preliminary study using gas chromatography-mass spectrometry.

BACKGROUND: Oral Lichen Planus is a chronic inflammatory disorder that affects the oral mucosa, with the reticular and erosive forms representing the primary clinical variants of the disease. Previous studies have shown that metabolic alterations may well be involved in the pathogenesis of the disease; however, the molecular mechanisms related to the clinicopathological differences between erosive and reticular forms remain unknown. METHODS: A comparative metabolomic analysis was performed on formalin-fixed and paraffin-embedded tissue samples of erosive (n = 6) and reticular (n = 10) oral lichen planus using gas chromatography-mass spectrometry. RESULTS: The metabolomic analysis showed a distinct profile between the two clinical variants. Five metabolites (cyclohexanamine, glycine, mannitol/sorbitol, methyl palmitate and trehalose) were significantly diminished in erosive oral lichen planus as compared to the reticular form. CONCLUSIONS: Reticular and erosive forms of oral lichen planus have a distinct metabolic profile. However, further studies using a large number of fresh tissue samples are necessary to confirm this data.

Oral lichen planus - Differential diagnoses, serum autoantibodies, hematinic deficiencies, and management.

Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease that occurs more frequently in middle-aged and elderly female patients. Previous studies indicate that OLP is a T-cell dysfunction-induced localized autoimmune disease. Clinically, six types of OLP, namely reticular, papular, plaque-like, atrophic/erosive, ulcerative, and bullous types, can be identified. OLP more commonly affects buccal mucosa, tongue, and gingiva. It always has a bilateral and symmetric distribution of the oral lesions. Plaque-like and atrophic/erosive OLP may be misdiagnosed as oral leukoplakia and oral erythroleukoplakia, respectively. Our previous study found serum autoantibodies in 195 (60.9%) of the 320 OLP patients. Specific serum anti-nuclear, anti-smooth muscle, anti-mitochondrial, gastric parietal cell, thyroglobulin, and thyroid microsomal autoantibodies are present in 28.1%, 8.4%, 1.6%, 26.3%, 21.3%, and 24.4% of 320 OLP patients, respectively. Furthermore, we also discovered that 21.9%, 13.6%, 7.1%, 0.3%, and 14.8% of 352 OLP patients have hemoglobin, iron, vitamin B12, and folic acid deficiencies, and abnormally high serum homocysteine level, respectively. Therefore, it is very important to examine the serum autoantibody, hematinic and homocysteine levels in OLP patients before starting the treatments for OLP patients. Because OLP is an immunologically-mediated disease, corticosteroids are the drugs of choice for treatment of OLP.

Scoring systems for Oral Lichen Planus used by differently experienced raters

Background: Scoring systems have been widely used to evaluate the severity and activity of oral lichen planus (OLP). The aim of the present study was to compare two existing (one modified) scoring systems in the evaluation of OLP severity and correlation with pain. Three differently experienced raters were involved. Material and Methods: Consecutive patients with OLP were assessed for pain using the Visual Analogue Scale and examined at 10 intraoral sites before starting (T0) and three weeks after (T1) steroid therapy (Clobetasol). Three differently experienced raters evaluated photographs using two scoring systems designated White-Erosive-Atrophic (WEA) modified from an older WEA system (WEA-MOD) and Reticular-erythematous-Ulcerative (REU) systems. WEA-MOD Kendall's W and interclass correlation coefficient were calculated and correlation between REU/WEA-MOD and pain was calculated using Spearman coefficient. Results: Most patients showed lesions on buccal mucosa (85-93,5%) and maxillary/mandibular gingivae (31,8- 31,2%), predominantly reticular. At T0, Kendall-W coefficients of 0.89 and 0.74 were obtained for the REU and WEA respectively. At T1, Kendall-W coefficients of 0.83 and 0.58 were obtained for the REU and WEA respectively. Interclass correlation coefficient ranged from 0.87 to 0.90 for REU and from 0.58 to 0.87 for WEA. REU and WEA scores significantly decreased after therapy (p< 0.000) as well as VAS (p< 0.05). REU score showed correlation with VAS. Conclusions: All the raters achieved comparable measures using REU whereas WEA and WEA-MOD seem less reproducible. REU seems to correlate to disease activity and pain (AU)

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Histopathological characterization of the oral lichenoid disease subtypes and the relation with the clinical data.

BACKGROUND: The aim of the study was to analyze the histopathological characteristics of samples with a diagnosis of oral lichenoid disease (OLD) and their link with the location and the type of clinical lesion, and the clinicopathological subtypes. MATERIAL AND METHODS: Retrospective study on 85 consecutive patients diagnosed with OLD (58 women and 27 men, mean age of 57.7 years). Clinical and histopathological characterization of each case (modified WHO criteria). Collection of the clinical and histopathological data of the lesions. Descriptive and comparative statistical analysis of the results. RESULTS: The 78.8% of the cases were considered clinically typical while the 21.2% were considered compatible. Histologically, 52.9% were classified as typical and 47.1% as compatible. Biopsies from "plaque-like" lesions presented hyperkeratosis (p>0.001) and epithelial dysplasia (p=0.06) more frequently. Furthermore, acute inflammation was more evident in erosive-ulcerative lesions (p=0.001). Differences regarding the location of the biopsy were statistically non-significant. However, 42.9% of the tongue biopsies showed epithelial dysplasia. CONCLUSIONS: The histopathological aspect of this disorder is not specific and does not allow us to differentiate between the main subtypes. Therefore, the main reasons to perform a biopsy in this disorder are to define the differential diagnosis and to rule out epithelial dysplasia or a carcinoma. The final histopathological result may be subject to the type of lesion that is biopsied.

[Analysis of type C behavior in patients with oral lichen planus].

OBJECTIVE: To assess type C behavior in patients with oral lichen planus (OLP) in order to provide basis for clinical prevention, treatment and psychological intervention of OLP. METHODS: Type C behavior scale was used on 85 OLP patients and 85 control patients, who were in accordance with the inclusion criteria, in order to investigate their type C behavior. The scale included 9 items: anxiety, depression, anger, anger toward inside (anger-in), anger toward outside (anger-out), reasoning, domination, optimism, and social support. Scores of the 9 items between OLP patients and control group were calculated under the instruction of the scale and were statistically analyzed, and OLP group was further stratified statistically by sex, reticulate-erosive-ulcerative (REU) pathological type and course of diseases, and the scores of each group were analyzed and compared. RESULTS: Among the 85 OLP patients, there were more females, more non-erosive lesion type, and the most common site for OLP was the buccal mucosa. The scores of the type-C behavior questionnaire for anxiety, depression, anger and optimism were respectively 43.01±7.47, 44.02±7.61, 21.56±5.26, 22.15±4.00 among the OLP patients and were 37.94±8.70, 39.58±7.35, 18.12±5.39, 24.05±3.23 among control group, with significant differences(P<0.05 for all) between the two groups. The female OLP patients had higher anxiety, depression, anger scores (43.21±6.97, 44.29±7.54, 21.64±5.09) and lower reasoning, domination, optimism scores (39.12±5.66, 16.29±3.95, 22.05±4.12) with significant differences (P<0.05 for all) compared with those of the female controls. The scores between male patients and male controls showed no significant difference. The patients with erosive lesions had higher anger score (22.94±5.26) than that of the patients without erosive lesions(20.60±5.03), with a significant difference(P<0.05). With the development of the disease, the tendency of anxiety and depression of the patients were more obvious, while optimism scores remained declining. The patients suffering more than 3 years of OLP had higher anger-toward-outside scores (17.36±3.35) than the patients suffering less than 3 years of OLP (15.19±3.99), with a significant difference (P<0.05). CONCLUSION: OLP patients showed an obvious type C behavior characteristic, especially in anxiety, depression, anger and low optimism. This research provides the C behavior characteristic of OLP for further psychological consultation or intervention during OLP treatment.

[Dynamic concept of oral lichen planus. The diagnosis easy at early stages may become difficult in ancient lichen planus]. / Concept actuel du lichen plan oral. Le diagnostic facile au début, peut devenir très difficile dans les lichens anciens.

Dynamic concept of oral lichen planus. The diagnosis easy at early stages may become difficult in ancient lichen planus. Lichen planus is a chronic inflammatory dermatosis of the skin, skin appendages and mucous membranes, which frequently affects the oral mucosa. Its aetiology still remains unknown, and currently accepted pathogenesis is that of an autoimmune cell-mediated disease. To the contrary of skin lichen planus, oral lichen planus is a long-term chronic disease with dynamic evolution, in which progressive and profound changes of the clinical and histopathological aspects occur over time and under the influence of various exogenous factors. By convention, in the history of the oral lichen planus four successive stages can be distinguished without well-defined boundaries between them. These stages can be defined as an initial phase; a long intermediate phase with alternating periods of activity and quiescence, which has a gradually increasing risk of malignant transformation; a late stage which activity is traditionally diminished; and a post-lichen cicatricial stage with an absent or negligible and undetectable activity, often undiagnosed because clinically unrecognized; in this stage, the lesion does not respond to usual treatments, but retains the same risk of malignant transformation.

MicroRNA-155-IFN-γ Feedback Loop in CD4(+)T Cells of Erosive type Oral Lichen Planus.

Oral lichen planus (OLP) is a T cell-mediated immune disorder, and we have indicated a Th1-dominated immune response in OLP. MicroRNA-155 (miR-155) could promote Th1 cells polarization. The present study aims to determine the role of miR-155 in immune response of OLP. The expression of miR-155 and the target mRNA was tested by Real-Time PCR. The serum levels of IL-2, 4, 10 and IFN-γ were examined with ELISA. Furthermore, in vitro study was built to observe the function of miR-155 in erosive-type OLP (EOLP). Finally, we determined the expression and correlation of miR-155 and SOCS1 in EOLP CD4(+) T cells. The results showed miR-155 was high related with the disease severities. Besides, serum IFN-γ was specifically increased in EOLP group, while IL-4 was decreased. In vitro studies showed miR-155 could reinforce IFN-γ signal transducer, and the induction of IFN-γ could also promote miR-155 expression in EOLP CD4(+) T cells. In addition, miR-155 levels were negatively related with SOCS1 mRNA expression in EOLP CD4(+) T cells. Our study revealed a positive miR-155- IFN-γ feedback loop in EOLP CD4(+) T cell, which might contribute to the Th1-dominated immune response. Furthermore, miR-155 could be used for the evaluation and treatment of OLP.

The impact of structured plaque control for patients with gingival manifestations of oral lichen planus: a randomized controlled study.

AIM: To evaluate the impact of a structured plaque control intervention on clinical and patient-centred outcomes for patients with gingival manifestations of oral lichen planus. MATERIALS AND METHODS: Eighty-two patients were recruited into a 20-week randomized controlled trial. The intervention was structured plaque control comprising powered tooth brushing and inter-dental cleaning advice. Control subjects continued with their normal dental plaque control regimen. The primary outcome measure was the oral health impact profile (OHIP) with secondary outcomes of pain, plaque index, mucosal disease score and cost-effectiveness. RESULTS: Overall, the intervention patients showed statistically significant improvements in OHIP sum ordinal and OHIP dichotomous scores compared with control. There were improvements in the functional limitation, psychological discomfort and physical disability domains at 4- and 20-weeks and in the psychological disability domain at 20-weeks. The intervention was successful in reducing plaque compared to control (p < 0.001) and improvements were observed using the mucosal disease indices at the 4- and 20-week follow-ups (p < 0.001). CONCLUSION: A structured plaque control intervention was effective in improving the oral health-related quality of life and clinically observed gingival lesions. This study provides evidence to include intensive plaque control within patients' initial and on-going management.

Disease scoring systems for oral lichen planus; a critical appraisal

The aim of the present study has been to critically review 22 disease scoring systems (DSSs) on oral lichen planus(OLP) that have been reported in the literature during the past decades. Although the presently available DSSs may all have some merit, particularly for research purposes, the diversity of both the objective and subjective parameters used in these systems and the lack of acceptance of one of these systems for uniform use, there is a need for an international, authorized consensus meeting on this subject. Because of the natural course of OLP characterized by remissions and exacerbations and also due to the varying distribution pattern and the varying clinical types, e.g. reticular and erosive, the relevance of a DSS based on morphologic parameters is somewhat questionable. Instead, one may consider to only look for a quality of life scoring system adapted for use in OLP patients

Disease scoring systems for oral lichen planus; a critical appraisal.

The aim of the present study has been to critically review 22 disease scoring systems (DSSs) on oral lichen planus (OLP) that have been reported in the literature during the past decades. Although the presently available DSSs may all have some merit, particularly for research purposes, the diversity of both the objective and subjective parameters used in these systems and the lack of acceptance of one of these systems for uniform use, there is a need for an international, authorized consensus meeting on this subject. Because of the natural course of OLP characterized by remissions and exacerbations and also due to the varying distribution pattern and the varying clinical types, e.g. reticular and erosive, the relevance of a DSS based on morphologic parameters is somewhat questionable. Instead, one may consider to only look for a quality of life scoring system adapted for use in OLP patients.

Epidermal growth factor receptor expression in different subtypes of oral lichenoid disease.

UNLABELLED: The oral lichenoid disease (OLD) includes different chronic inflammatory processes such as oral lichen planus (OLP) and oral lichenoid lesions (OLL), both entities with controversial diagnosis and malignant potential. Epidermal growth factor receptor (EFGR) is an important oral carcinogenesis biomarker and overexpressed in several oral potentially malignant disorders. OBJECTIVES: To analyze the EGFR expression in the OLD to find differences between OLP and OLL, and to correlate it with the main clinical and pathological features. MATERIAL AND METHODS: Forty-four OLD cases were studied and classified according to their clinical (Group C1: only papular lesions / Group C2: papular and other lesions) and histopathological features (Group HT: OLP-typical / Group HC: OLP-compatible) based in previous published criteria. Standard immunohistochemical identification of EGFR protein was performed. Comparative and descriptive statistical analyses were performed. RESULTS: Thirty-five cases (79.5%) showed EGFR overexpression without significant differences between clinical and histopathological groups (p<0.05). Histological groups showed significant differences in the EGFR expression pattern (p=0.016). Conlusions: All OLD samples showed high EGFR expression. The type of clinical lesion was not related with EGFR expression; however, there are differences in the EGFR expression pattern between histological groups that may be related with a different biological profile and malignant risk.

Interleukin-6 and neopterin levels in the serum and saliva of patients with Lichen planus and oral Lichen planus.

BACKGROUND: Lichen planus together with its oral variant is a chronic, inflammatory disease of the skin and the mucosa of unclear aetiology and with an unpredictable course that still poses a major problem in terms of diagnosis and treatment. The objective of this study was to assess the concentrations of interleukin-6 (IL-6) and neopterin in saliva and serum of patients with lichen planus (including reticular and erosive form of oral lichen planus) and to compare them with the concentrations observed in healthy controls. METHODS: The study material comprised serum and saliva samples from 56 patients diagnosed with lichen planus and 56 healthy volunteers. The ELISA test was used to measure concentrations of IL-6 and neopterin in the serum and saliva of the study participants. RESULTS: The concentrations of IL-6 in saliva and serum of patients with lichen planus were significantly higher than in controls (P = 0.0002; P < 0.0001). The difference remains significant after adjustment for gingivitis and age. Patients with atrophic-erosive oral lichen planus had significantly higher IL-6 concentrations in their saliva compared to patients with reticular form of disease (P = 0.01). The concentrations of neopterin were significantly higher in the serum but not in saliva of lichen planus patients vs. controls (P <0.0001). CONCLUSIONS: Serum levels of proinflammatory cytokines IL-6 and neopterin are increased in lichen planus as well as the salivary concentrations of IL-6. The differences observed in IL-6 levels in patients with erosive-atrophic forms of oral lichen planus may indicate a substantial role played by the cytokine in the disease.

Oral lichenoid tissue reactions: diagnosis and classification.

The concept of lichenoid tissue reaction/interface dermatitis was introduced in dermatology to define a number of diverse inflammatory skin diseases linked together by the presence of common histopathological features. Similarly to the skin, the oral mucosa is affected by a variety of oral lichenoid lesions. Oral LTRs (OLTRs) include: oral lichen planus; oral lichenoid contact lesion; oral lichenoid drug reaction; oral lichenoid lesions of graft-versus-host disease; oral discoid lupus erythematosus; oral lesions of systemic lupus erythematosus; erythema multiforme; paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome; chronic ulcerative stomatitis and lichen planus pemphigoid. Traditionally, diagnosis of OLTRs relies on clinical and histological correlation but in several instances this approach fails to provide a reliable diagnosis. Inclusion of molecular techniques may refine our ability to differentiate OLTRs.

Salivary interleukin-6 and -8 in patients with oral cancer and patients with chronic oral inflammatory diseases.

BACKGROUND: Previous research has indicated that salivary interleukin (IL)-6 and IL-8 are potential biomarkers for oral squamous cell carcinoma (OSCC). However, their levels have been found to be significantly elevated in patients with chronic periodontitis (CP) or oral lichen planus (OLP). The data also showed wide variations in levels among the different studies, and no standardization procedure was ever performed. Therefore, the objective of this study is to determine whether CP or OLP confounds the use of IL-6 or IL-8 for OSCC detection. METHODS: Saliva samples were collected from five groups: OSCC before treatment (n = 18); CP (n = 21); disease-active OLP (n = 21); disease-inactive OLP (n = 20); and healthy controls (n = 21). IL-6 and IL-8 concentrations (determined by enzyme-linked immunosorbent assays) were compared, using total salivary protein-standardized levels to validate the data. The Kruskal-Wallis test (α = 0.05) followed by pairwise Mann-Whitney U (post hoc) tests with Bonferroni adjustments (α = 0.00625) were used for statistical analysis. RESULTS: Salivary IL-6 levels were significantly higher in patients with OSCC than in patients with CP (P <0.001), disease-active OLP (P = 0.001), disease-inactive OLP (P <0.001), and healthy controls (P <0.001). Salivary IL-8 levels were significantly higher in patients with OSCC than in patients with CP (P <0.001), but only marginally significantly higher than in healthy controls (P = 0.014). Statistical results of standardized IL-6 and IL-8 levels were consistent with the non-standardized levels in all pairs except one. CONCLUSION: Salivary IL-6 may be a useful biomarker in the detection of OSCC, unconfounded by CP or OLP.

Interferon-γ and interleukin-4 detected in serum and saliva from patients with oral lichen planus.

Our previous salivary study had demonstrated an apparent T helper 2 (Th2)-predominance in saliva of oral lichen planus (OLP) patients and suggested a potential of salivary interleukin-4 (IL-4) as a biomarker for monitoring disease severity. To further determine the consistency of Th1/Th2 bias of OLP, this study investigated the expression profile of interferon-γ (IFN-γ) and IL-4 in serum and the relationship of the serum levels of these cytokines with their saliva partners. Sixty ethnic Chinese patients with OLP (40 of the erythematous/ulcerative form and 20 of the reticular form) were recruited for this study, with 40 age-sex-matched healthy volunteers as control group. IFN-γ and IL-4 levels in serum and paired saliva samples were screened by enzyme-linked immunosorbent assay. OLP patient showed a low-level IFN-γ but high-level IL-4 expression profile in both serum and saliva, with a lower IFN-γ/IL-4 ratio. Serum IL-4 level in the erythematous/ulcerative group was significantly higher than that in the reticular group. Serum levels of IFN-γ and IL-4 were significantly and positively correlated with their saliva partners. These results provided more evidence for Th2 cytokine-predominant immune imbalance in OLP, as well as the potential of IL-4 as the biomarker for monitoring severity of OLP.

p53 as a neoplastic biomarker in patients with erosive and plaque like forms of oral lichen planus.

AIM: Unstimulated whole salivary p53 was assessed in patients suffering from erosive and plaque-like form of oral lichen planus (OLP). MATERIALS AND METHODS: Eighteen patients with erosive form, 17 patients suffering from plaque-like form and 38 noninvolvement subjects were enrolled. The unstimulated whole saliva p53 level was assayed by ELISA. RESULTS: The mean concentration of salivary p53 was significantly higher in patients with plaque-like form compared to both patients with erosive form and the control group. CONCLUSION: We conclude that plaque like form of OLP is important in view of the potential for malignancy and is not safety form. CLINICAL SIGNIFICANCE: It seems that all forms of OLP must be considered accurately, should be followed up with biannual examinations, and if possible, assessment of salivary p53 every year.

A comparative immunohistochemical and immunophenotypical study on lymphocytes expression in patients affected by oral lichen planus.

BACKGROUND: Oral lichen planus (OLP) is an immune-mediated mucocutaneous disease of uncertain aetiology. OLP has many manifestations: reticular, erosive, atrophic, plaque like, papular, bullous, with unique etiopathogenetic working. The purpose of this study is to find a link between different clinical types of lichen and the alterations of lymphocytes on peripheral blood and oral mucosa. MATERIALS AND METHODS: A total of 21 patients were enrolled in this study. The mean age of patients was 53.82 years, between 31 and 78 years. OLP Diagnosis was afterwards confirmed by histopathology. Selected patients underwent to clinical evaluation, lesion characterization, incisional biopsy, samples histological analysis, peripheral blood collection. Blood specimens were submitted to cell count determination with differential, characterization of populations and circulating lymphocyte subpopulations using monoclonal antibodies in flow cytometry. Referring to the clinical presentation of lesions, patients were divided in two groups: red lesions (RL) and white lesions (WL) and compared with an age-matched control group. RESULTS: The results of the immunophenotypic study showed correlation between WL and the expression of CD19 lymphocytes (r = 0.693, P = 0.0005). The results of immunohistochemical study performed on histological specimens showed a significant correlation between RL group and expression of all lymphocyte tested (CD3 r = 0.722 P = 0.0002, CD4 r = 0.579 P = 0.0060, CD56 r = 0.513 P = 0.0173, CD8 r = 0.548 P = 0.0102). CONCLUSIONS: We assume there is the responsibility of the expression of lymphocytes, not only type but also as quantity, in determining RL or WL manifestation of OLP. Circulating lymphocytes may have a role, too.

Oral lichen planus.

Oral lichen planus is a common immunologically mediated mucocutaneous disease. These lesions have varied clinical presentations and symptoms, which include reticular, erosive, or erythematous forms. This article reviews the diagnosis and management of oral lichen planus.

Analysis of the expression of heat-shock protein 27 in patients with oral lichen planus.

OBJECTIVE: Heat-shock protein 27 (hsp27) has been implicated in several biological events. In this experimental study, we aimed at analysing, for the first time, the expression of hsp27 in the diverse stages of oral lichen planus (OLP) lesions. MATERIALS AND METHODS: Thirty-six biopsy specimens of patients with OLP and 10 of healthy patients were selected. OLP specimens were divided into three groups: G1 - moderate or mildly active OLP; G2 - active or moderately active atrophic OLP; G3 - mild or inactive atrophic OLP. Hsp27 expression was analysed by immunohistochemistry (staining intensity and percentage of stained cells), and results of staining were compared between the different groups. Gender, age and anatomical location were also studied. RESULTS: In the basal layer, an increase of hsp27 expression in both G2 and G3 was observed when compared to G1 and control group. In contrast, a decrease of hsp27 expression in the superficial layer was observed in all groups when compared to control group. CONCLUSION: The increased expression of Hsp27 in the basal layer observed during the OLP evolution and the less staining in the superficial layers in all cases of OLP suggest that hsp27 may have a role in the OLP pathogenesis.