Strong claudin 5 expression is a poor prognostic sign in pancreatic adenocarcinoma

We investigated the expression of claudin 5 in 88 ductal adenocarcinomas of the pancreas. The results were correlated with patient prognosis, with claudin 5 expression in blood vessels, with the expression level of bcl2 and bax and with apoptosis. Claudin 5 expression was detected in 24 (38%) cases. It was not associated with tumour size or spread, but strong claudin 5 expression correlated with a worse survival (p = 0.005). Claudin 5 also associated with a higher extent of apoptosis and greater expression of bax protein. In the tumour vasculature, some vessels displayed a loss of claudin 5 expression. The presence of this loss was associated with tumour grade and the presence of nodal metastases (p = 0.02, p = 0.022, respectively). These results indicate that claudin 5 is upregulated in a proportion of pancreatic ductal adenocarcinomas. The association of strong claudin 5 expression with a worse survival is in line with some earlier reports indicating that this protein is involved with increased locomotion and more aggressive spread of carcinomas. The association of claudin 5 with apoptosis and bax might be due to stronger cellular kinetics found in such tumours. The loss of claudin 5 expression in the tumour vasculature points to a leaky vessel type; this might also ease the access of tumours to vessels and be reflected in its association with the presence of nodal metastases.

GASC1 expression in lung carcinoma is associated with smoking and prognosis of squamous cell carcinoma

GASC1 (gene amplified in squamous cell carcinoma 1) encodes a nuclear protein that epigenetically catalyses the lysine demethylation of histones. We investigated the expression of GASC1 in different histological subtypes of lung cancer (n=289). Percentage value of GASC1 immunohistochemical expression was evaluated separately in the nuclei and cytoplasms of epithelial cancer cells. The results were compared with clinicopathologic factors and the smoking history of the patients. In lung tumor cells, 38% of nuclei and 54% of the cytoplasms stained positive for GASC1. Adenocarcinomas expressed more GASC1 nuclear (p=0.00011) and cytoplasmic (p=0.00074) positivity than squamous cell carcinoma. Smokers displayed less nuclear and cytoplasmic GASC1 expression than non-smokers (p=0.028 and p=0.036, respectively). Similarly, patients with more cytoplasmic positive staining had fewer pack years (p=0.043). Nuclear GASC1 expression had an impairing effect on survival when all histological lung cancer types were analysed together (p=0.039) and separately in squamous cell lung carcinoma (p=0.016). The results reveal that GASC1 expression is higher in adenocarcinoma than squamous cell carcinoma. Smoking decreases GASC1 expression in tumor cells, indicating that tobacco smoke may influence the methylation of histone 3 lysine residues in lung cancer. Nonetheless, nuclear GASC1 predicts a poor prognosis, especially in squamous cell carcinoma.

Claudins 1, 2, 3, 4, 5 and 7 in solar keratosis and squamocellular carcinoma of the skin

Claudins are tight junction proteins regulating the paracellular permeability of cell layers. We investigated the expression of claudins 1, 2, 3, 4, 5 and 7 in a sample set consisting of a total of 93 cases representing normal skin, actinic keratoses and squamous cell carcinomas of the skin. There were several changes found in claudin expression. Claudin 1 appeared to be progressively decreased in solar keratosis and skin squamous cell carcinomas compared to normal skin while expression of claudin 2 was increased. With claudins 3 and 5 occasional immunoreactivity was found in squamous cell carcinomas. Claudins 4 and 7 were variably expressed in skin neoplasia compared to normal skin. According to the results expression of claudins 1 and 2 change in parallel with the severity of the epidermal preneoplastic and neoplastic lesions thus probably influencing the disturbed epithelial polarity characteristic of these lesions. Claudin 1 under- and claudin 2 overexpression also lead to a leakier epithelial barrier function of the skin with a resulting damage to skin epithelial resistance. Other claudins investigated in this study did not show progressive changes even though occasional overexpression of them was found in skin squamous cell carcinoma.

Nuclear Nrf2 expression is related to a poor survival in pancreatic adenocarcinoma

The aim of this study was to investigate the expression of Nrf2, sulfiredoxin and DJ1 in pancreatic cancer. The expression of Nrf2, sulfiredoxin and DJ1 was studied immunohistochemically in a large set of pancreatic adenocarcinomas consisting of 103 cases. Eighty six percent of the cases showed cytoplasmic Nrf2 and 24% nuclear Nrf2 positivity. Sulfiredoxin positivity was observed in 54% and DJ1 positivity in all cases. Nuclear Nrf2 positivity had an association with sulfiredoxin (p=0.019) and was associated with a poor survival (p=0.010). Stage IV tumors tended to have a more nuclear Nrf2 expression (p=0.080). DJ1 expression was more often found in well-differentiated tumors (p=0.012), and DJ1 expression was associated with better survival (p=0.020). According to the results, nuclear Nrf2 expression predicts a worse survival in pancreatic adenocarcinoma, which is in keeping with its protection of cells against oxidative or xenobiotic stress. In accordance with Nrf2's regulation of the synthesis of sulfiredoxin, there was an association between them (p=0.019). DJ1 had no association with Nrf2, and its expression predicted a better survival of patients.

MiR-221/222 target the DNA methyltransferase MGMT in glioma cells

Glioblastoma multiforme (GBM) is one of the most deadly types of cancer. To date, the best clinical approach for treatment is based on administration of temozolomide (TMZ) in combination with radiotherapy. Much evidence suggests that the intracellular level of the alkylating enzyme O⁶-methylguanine–DNA methyltransferase (MGMT) impacts response to TMZ in GBM patients. MGMT expression is regulated by the methylation of its promoter. However, evidence indicates that this is not the only regulatory mechanism present. Here, we describe a hitherto unknown microRNA-mediated mechanism of MGMT expression regulation. We show that miR-221 and miR-222 are upregulated in GMB patients and that these paralogues target MGMT mRNA, inducing greater TMZ-mediated cell death. However, miR-221/miR-222 also increase DNA damage and, thus, chromosomal rearrangements. Indeed, miR-221 overexpression in glioma cells led to an increase in markers of DNA damage, an effect rescued by re-expression of MGMT. Thus, chronic miR-221/222-mediated MGMT downregulation may render cells unable to repair genetic damage. This, associated also to miR-221/222 oncogenic potential, may poor GBM prognosis.

Polarity of Mature Human Odontoblasts

Odontoblast polarization is based on histological appearance as columnar cells with asymmetric disposition of organelles and plasma membrane domains. However, little is known about the odontoblast plasma membrane organization. We investigated odontoblast membrane polarity using influenza virus hemagglutinin and vesicular stomatitis virus glycoprotein as model proteins in mature human odontoblast organ culture. We also examined the distribution patterns of aquaporin 4 and 5, which are basolateral and apical proteins in epithelial cells, respectively. Confocal microscopy immunofluorescence and electron microscopy demonstrated that the apical markers located at the surface toward pulp and basolateral markers located at the plasma membrane of odontoblast processes. Therefore, odontoblast plasma membrane polarity was different from that in epithelial cells. Also, certain lectins stained odontoblast processes while others stained the soma, reflecting the different natures of their membrane domains. Strong ZO-1 and weaker claudin expression suggest weak tight junctions in the odontoblasts. TGF-β1 showed a tendency to reinstate the expression of selected TJ genes, indicating that TGF-β1 may control odontoblast cell layer integrity by controlling tight junction protein expression.

Transmembrane prostatic acid phosphatase (TMPAP) interacts with snapin and deficient mice develop prostate adenocarcinoma

The molecular mechanisms underlying prostate carcinogenesis are poorly understood. Prostatic acid phosphatase (PAP), a prostatic epithelial secretion marker, has been linked to prostate cancer since the 1930's. However, the contribution of PAP to the disease remains controversial. We have previously cloned and described two isoforms of this protein, a secretory (sPAP) and a transmembrane type-I (TMPAP). The goal in this work was to understand the physiological function of TMPAP in the prostate. We conducted histological, ultra-structural and genome-wide analyses of the prostate of our PAP-deficient mouse model (PAP^−/−) with C57BL/6J background. The PAP^−/− mouse prostate showed the development of slow-growing non-metastatic prostate adenocarcinoma. In order to find out the mechanism behind, we identified PAP-interacting proteins byyeast two-hybrid assays and a clear result was obtained for the interaction of PAP with snapin, a SNARE-associated protein which binds Snap25 facilitating the vesicular membrane fusion process. We confirmed this interaction by co-localization studies in TMPAP-transfected LNCaP cells (TMPAP/LNCaP cells) and in vivo FRET analyses in transient transfected LNCaP cells. The differential gene expression analyses revealed the dysregulation of the same genes known to be related to synaptic vesicular traffic. Both TMPAP and snapin were detected in isolated exosomes. Our results suggest that TMPAP is involved in endo-/exocytosis and disturbed vesicular traffic is a hallmark of prostate adenocarcinoma.

Depth of invasion, tumor budding, and worst pattern of invasion: prognostic indicators in early-stage oral tongue cancer

Background

Oral (mobile) tongue squamous cell carcinoma (SCC) is characterized by a highly variable prognosis in early-stage disease (T1/T2 N0M0). The ability to classify early oral tongue SCCs into low-risk and high-risk categories would represent a major advancement in their management.

Methods

Depth of invasion, tumor budding, histologic risk-assessment score (HRS), and cancer-associated fibroblast (CAF) density were studied in 233 cases of T1/T2 N0M0 oral tongue SCC managed in 5 university hospitals in Finland.

Results

Tumor budding (≥5 clusters at the invasive front of the tumor) and depth of invasion (≥4 mm) were associated with poor prognosis in patients with early oral tongue SCC (hazard ratio [HR], 2.04; 95% confidence interval [CI], 1.17–3.55; HR, 2.55; 95% CI, 1.25–5.20, respectively) after multivariate analysis. The HRS and CAF density did not predict survival. However, high-risk worst pattern of invasion (WPOI), a component of HRS, was also an independent prognostic factor (HR, 4.47; 95% CI, 1.59–12.51).

Conclusion

Analyzing the depth of invasion, tumor budding, and/or WPOI in prognostication and treatment planning of T1/T2 N0M0 oral tongue SCC is recommended.

Matriptase-2 gene (TMPRSS6) variants associate with breast cancer survival, and reduced expression is related to triple-negative breast cancer

Matriptase-2 (TMPRSS6) has been identified as a breast cancer risk factor. Here, we examined relationships between TMPRSS6 genetic variations and breast cancer risk and survival, and determined the gene and protein expressions in breast tumors and assessed their clinical importance. Thirteen TMPRSS6 polymorphisms were genotyped in 462 invasive breast cancer cases and 458 controls. Gene expression was analyzed from 83 tumors and protein expression from 370 tumors. We then assessed the statistical significance of associations among genotypes, clinicopathological characteristics and survival. The TMPRSS6 variant rs2543519 was associated with breast cancer risk (p = 0.032). Multivariate analysis showed that four variants had effects on survival-rs2543519 (p = 0.017), rs2235324 (p = 0.038), rs14213212 (p = 0.044) and rs733655 (p = 0.021)-which were used to create a group variable that was associated with poorer prognosis correlating with more alleles related to reduced survival (p = 0.006; risk ratio, 2.375; 95% confidence interval, 1.287-4.382). Low gene expression was related to triple-negative breast cancer (p = 0.0001), and lower protein expression was detected in undifferentiated (p = 0.019), large (p = 0.014) and ductal or lobular tumors (p = 0.036). These results confirm the association of TMRRSS6 variants with breast cancer risk and survival. Matriptase-2 levels decrease with tumor progression, and lower gene expression is seen in poor-prognosis-related triple-negative breast cancers. Our study is the first to show that matriptase-2 gene variants are related to breast cancer prognosis, supporting matriptase-2 involvement in tumor development.

Cell cycle regulation score predicts relapse-free survival in non-germinal centre diffuse large B-cell lymphoma patients treated by means of immunochemotherapy

OBJECTIVES

The cell cycle is under strict regulation by the retinoblastoma, p53 and p27 pathways, and the disruption of these pathways is an important characteristic of diffuse large B-cell lymphoma (DLBCL). In this study, we wanted to assess the function and prognostic significance of these pathways in DLBCL patients.

METHODS

Tissue samples from 120 DLBCL patients treated by means of R-CHOP-type chemotherapy were stained for the cell cycle-regulating proteins p16, p21, p27 and p53, and the germinal centre (GC) phenotype was determined according to Hans' algorithm. Based on the number of impaired cell cycle-regulating pathways a predictive score was obtained, covering three different prognostic groups: a 'favourable' group with damage in 0-1 of the studied pathways, a 'poor' group with damage in all three pathways and an 'intermediate' group comprising the rest of the patients.

RESULTS

The prognosis of non-GC DLBCL patients was significantly poorer vs. GC phenotype patients (P = 0.015). The prognostic score proved especially useful among non-GC phenotype patients, with 3-yrs relapse-free survival of 100% vs. 62.6% vs. 24.3% in the 'favourable-', 'intermediate-' and 'poor prognosis' groups, respectively (P = 0.003).

CONCLUSION

The prognosis of non-GC DLBCL patients is progressively impaired with the accumulation of damage in different cell cycle-regulating pathways.

Expression of claudins relates to tumour aggressivity, location and recurrence in ependymomas

The aim of our study was to assess the nature and importance of claudin expression in grade I-III ependymomas. The expression of claudins 2-5, 7, 10, TWIST, and ZEB1 were investigated in a series of 61 ependymomas using immunohistochemistry. All the claudins were expressed in ependymomas, except for CLDN4. CLDN5 positive tumours were associated with higher grade (p=0.049), whereas CLDN10 was lower in higher grade tumours (p=0.039). CLDN5 and CLDN3 were overexpressed in ependymomas of cerebral location (p=0.036, p=0.007, respectively). CLDN5 positive tumours showed more nuclear atypia, endothelial proliferation, mitosis, and hypercellularity (p=0.007, p=0.018, p=0.041, p=0.010, respectively). CLDN5 positivity correlated to higher proliferation (p=0.015). CLDN7 was more often positive in primary tumours (p=0.041). Positive ZEB1 expression was associated with CLDN2 negativity (p=0.031). TWIST-negative tumours were more often also CLDN5 and 10 negative (p=0.013, p=0.017, respectively). CLDN5 was related to more aggressive tumours compared to CLDN2 and 10, which tended to display a better degree of differentiation and a better prognosis. CLDN2 and CLDN5 were expressed commonly in ependymomas, while the parental ependymal cells in the central nervous system were usually negative. Evidently, claudins influence growth and differentiation in ependymomas.

[From metastases to the search of primary tumor]

A metastasis may be the first sign of a malignant tumor. Most commonly this is a pathologically enlarged lymph node, but other symptoms caused by metastases such as pathologic bone fractures may also produce the first symptom of the disease. When searching for the primary tumor, the site of the metastasis and the patient's clinical data must be taken into consideration. Along with possible additional investigations, imaging studies and a biopsy taken from the metastasis lead to diagnosis in 90% of cases. The origin of metastasized tumors remains unraveled in approximately 3 to 5% of cases.

Divergence of tight and adherens junction factors in alveolar epithelium in pulmonary fibrosis

It has been proposed that an epithelial injury may be one of the multiple primary events in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The aim of this study was to characterize the tight junction and adherens junction proteins in normal human lung, IPF, cryptogenic organizing pneumonia, and asbestosis. We determined the immunohistochemical cell-specific expression of tight junction proteins claudin-1, claudin-2, claudin-3, claudin-4, claudin-5, and claudin-7, as well as 3 adherens junction proteins, E-cadherin, N-cadherin, and β-catenin. We further analyzed the expression of claudin-1, claudin-3, and claudin-4 and E-cadherin, N-cadherin, and β-catenin at the transcriptional level by quantitative real-time reverse transcriptase polymerase chain reaction. The expression levels of both tight junction and adherens junction proteins were elevated in regenerative alveolar epithelium in pulmonary fibrosis as compared with the expression of these proteins in normal alveolar epithelium. In particular, the expression levels of claudins-1 and claudin-3 were clearly elevated in all diseases. Furthermore, the amounts of adherens junction proteins messenger RNAs (mRNAs) were also all increased in pulmonary fibroses in comparison with healthy controls, with N-cadherin showing the greatest increase in mRNA levels in all diseases. However, the amounts of claudin-1, claudin-3, and claudin-4 mRNAs in fibrotic lung were similar to or even lower than those measured in the healthy controls. It is possible that the diminished capacity to produce claudin mRNAs may be one explanation for poor repair capacity of alveolar epithelial cells in IPF.

Snail promotes an invasive phenotype in lung carcinoma

Background

Snail is a transcriptional factor which is known to influence the epitheliomesenchymal transition (EMT) by regulating adhesion proteins such as E-cadherin and claudins as well as matrix metalloproteases (MMP).

Methods

To evaluate the functional importance of snail, a transciptional factor involved in EMT in lung tumors, we investigated its expression in a large set of lung carcinomas by immunohistochemistry. Expression of snail and effects of snail knockdown was studied in cell lines.

Results

Nuclear snail expression was seen in 21% of cases this being strongest in small cell lung carcinomas (SCLC). There was significantly greater snail expression in SCLC compared to squamous cell or adenocarcinoma. Positive snail expression was associated with poor survival in the whole material and separately in squamous cell and adenocarcinomas. In Cox regression analysis, snail expression showed an independent prognostic value in all of these groups. In several cell lines knockdown of snail reduced invasion in both matrigel assay and in the myoma tissue model for invasion. The influence of snail knockdown on claudin expression was cell type specific. Snail knockdown in these cell lines modified the expression of MMP2 and MMP9 but did not influence the activation of these MMPs to any significant degree.

Conclusions

The results show that snail plays an important role in the invasive characteristics of lung carcinoma influencing the survival of the patients. Snail knockdown might thus be one option for targeted molecular therapy in lung cancer. Snail knockdown influenced the expression of claudins individually in a cell-line dependent manner but did not influence MMP expressions or activations to any significant degree.

Histone demethylase GASC1--a potential prognostic and predictive marker in invasive breast cancer

Background

The histone demethylase GASC1 (JMJD2C) is an epigenetic factor suspected of involvement in development of different cancers, including breast cancer. It is thought to be overexpressed in the more aggressive breast cancer types based on mRNA expression studies on cell lines and meta analysis of human breast cancer sets. This study aimed to evaluate the prognostic and predictive value of GASC1 for women with invasive breast cancer.

Methods

All the 355 cases were selected from a cohort enrolled in the Kuopio Breast Cancer Project between April 1990 and December 1995. The expression of GASC1 was studied by immunohistochemistry (IHC) on tissue microarrays. Additionally relative GASC1 mRNA expression was measured from available 57 cases.

Results

In our material, 56% of the cases were GASC1 negative and 44% positive in IHC staining. Women with GASC1 negative tumors had two years shorter breast cancer specific survival and time to relapse than the women with GASC1 positive tumors (p=0.017 and p=0.034 respectively). The majority of GASC1 negative tumors were ductal cases (72%) of higher histological grade (84% of grade II and III altogether). When we evaluated estrogen receptor negative and progesterone receptor negative cases separately, there was 2 times more GASC1 negative than GASC1 positive tumors in each group (chi2, p= 0.033 and 0.001 respectively). In the HER2 positive cases, there was 3 times more GASC1 negative cases than GASC1 positives (chi2, p= 0.029). Patients treated with radiotherapy (n=206) and hormonal treatment (n=62) had better breast cancer specific survival, when they were GASC1 positive (Cox regression: HR=0.49, p=0.007 and HR=0.33, p=0.015, respectively). The expression of GASC1 mRNA was in agreement with the protein analysis.

Conclusions

This study indicates that the GASC1 is both a prognostic and a predictive factor for women with invasive breast cancer. GASC1 negativity is associated with tumors of more aggressive histopathological types (ductal type, grade II and III, ER negative, PR negative). Patients with GASC1 positive tumors have better breast cancer specific survival and respond better to radiotherapy and hormonal treatment.

Peroxiredoxins and their expression in ependymomas

AIMS

Peroxiredoxins I-VI (Prxs) have recently been shown to have a role in the tumorigenesis of astrocytic brain tumours. In some tumour types they are associated with Nrf2 (transcription factor NF-E2-related factor), a sensor of oxidative stress, and DJ-1 (also known as PARK7), a protein known to stabilise Nrf2.

METHODS

We investigated the immunohistochemical expression of Prxs I-VI, Nrf2 and DJ-1 in a total of 76 ependymomas and their relationship with clinicopathological features of these tumours.

RESULTS

There was a significant expression of all Prxs except Prx IV in the ependymomas. Strong nuclear and cytoplasmic expression of Nrf2 could be detected in these tumours. Prx I expression was significantly associated with cytoplasmic and nuclear Nrf2 expression. Prx I expression was also associated with tumour site, with cerebellar ependymomas having a lower expression of Prx I than other tumours. DJ-1 did not associate with Prxs but nuclear DJ-1 had an inverse association with nuclear Nrf2. Cytoplasmic DJ-1 associated with worse survival in ependymoma patients.

CONCLUSIONS

This study indicates that oxidative mechanisms as reflected by Nrf2 expression are highly activated in ependymomas. Prxs, especially Prx I, were associated with Nrf2 expression, suggesting a role for Nrf2 in Prx I synthesis in ependymomas. While DJ-1 did not associate with any of the Prxs, its expression was associated with worsened patient survival and could have a role as a prognostic marker in ependymomas.

Low TLR9 expression defines an aggressive subtype of triple-negative breast cancer

Toll-like receptor-9 (TLR9) is a DNA receptor widely expressed in cancers. Although synthetic TLR9 ligands induce cancer cell invasion in vitro, the role of TLR9 in cancer pathophysiology is unclear. We discovered that low tumor TLR9 expression is associated with significantly shortened disease-specific survival in patients with triple negative but not with ER+ breast cancers. A likely mechanism of this clinical finding involves differential responses to hypoxia. Our pre-clinical studies indicate that while TLR9 expression is hypoxia-regulated, low TLR9 expression has different effects on triple negative and ER+ breast cancer invasion in hypoxia. Hypoxia-induced invasion is augmented by TLR9 siRNA in triple negative, but not in ER+ breast cancer cells. This is possibly due to differential TLR9-regulated TIMP-3 expression, which remains detectable in ER+ cells but disappears from triple-negative TLR9 siRNA cells in hypoxia. Our results demonstrate a novel role for this innate immunity receptor in cancer biology and suggest that TLR9 expression may be a novel marker for triple-negative breast cancer patients who are at a high risk of relapse. Furthermore, these results suggest that interventions or events, which induce hypoxia or down-regulate TLR9 expression in triple-negative breast cancer cells may actually induce their spread.

Increased hyaluronan content and stromal cell CD44 associate with HER2 positivity and poor prognosis in human breast cancer

Previous in vitro studies have suggested interactions between hyaluronan (HA), CD44 and HER2. We have studied the expression of HA and CD44 in a material of 278 breast cancer cases, half of which were HER2-positive. Intense stromal HA staining was associated with HER2 positivity, large tumor size, lymph node positivity, hormone receptor negativity, poor differentiation, a high body mass index, increased relapse rate and shortened overall survival. Among the 139 HER2-positive cases, the relapse rate was associated with the intensity of stromal HA staining as most of the relapses occurred in the cases with intense stromal HA staining. The presence of HA in the carcinoma cells was related to the frequency of relapses as none of the patients without HA in carcinoma cells experienced a relapse, whereas 33.3% of those with a high percentage of HA-positive carcinoma cells suffered a relapse. CD44 positivity in carcinoma cells was related to poor differentiation, postmenopausal status and triple negative breast carcinoma. CD44 positivity in stromal cells was associated with HER2 positivity, large tumor size, hormone receptor negativity, poor differentiation, increased relapse rate and shortened overall survival. The association between HER2 positivity and intense stromal HA staining indicates that HA could be one of the factors involved in the unfavorable outcome of HER2-positive patients. This study also suggests that HA in breast carcinoma cells and CD44 in stromal cells may have clinical significance.

TLR4 and TLR9 are induced in oral lichen planus

BACKGROUND

The role of Toll-like receptors (TLRs) has been elucidated in many human infectious, autoimmune and neoplastic diseases. Previously, TLR2 and TLR4 expression in oral lichen planus (OLP) was described. The aim of our study was to examine expression patterns of TLR4 and TLR9 in normal oral mucosa and OLP and describe the effect of topical tacrolimus treatment on the expression of TLR4 and TLR9 in OLP.

METHODS

Toll-like receptor 4 and TLR9 expression was analysed by immunohistochemistry in five samples of normal oral mucosa and 50 samples of OLP (31 representing clinically white and 19 clinically erythematous/erosive lesions). We evaluated also the effect of topical tacrolimus on TLR4 and TLR9 expression in a patient with OLP.

RESULTS

Toll-like receptor 4 and TLR9 expression was increased in OLP epithelium compared with normal epithelium (P < 0.001); no significant difference between the two clinical types of OLP was observed. TLR9 expression was strongest in the superficial layer of the epithelium (P < 0.001), while the expression of TLR4 was strongest in the basal layer (P < 0.001). Treatment of OLP lesions with topical tacrolimus resulted in clinical improvement but had no effect on TLR expression levels.

CONCLUSIONS

Toll-like receptor 4 and TLR9 are induced in OLP; our finding confirms the results of a previous study. TLR4 and TLR9 may play a part in the pathogenesis of OLP. Further studies are needed to dissect the definitive role of TLRs in OLP pathogenesis and progression and to determine the effect of tacrolimus on the function of TLRs.