Expression of PD-L1 is HPV/P16-independent in oral squamous cell carcinoma.

Objectives: This study aimed to investigate the expression of programmed death-ligand 1 (PD-L1) and its associations with human papillomavirus (HPV) 16/18 DNA status, p16 expression, demographic, clinicopathologic and risk parameters in patients with oral squamous cell carcinoma (OSCC). Study design: A total of 85 formalin-fixed, paraffin-embedded OSCC specimens were collected. HPV16/18 DNA was detected by polymerase chain reaction. PD-L1 and p16 expressions were assessed using immunohistochemical technique. The immunostaining scores were calculated by combined positive score (CPS), previously described. The positive scoring value was determined at CPS ≥1, recommended by FDA. The associations between PD-L1 expression and HPV16/18 DNA status, p16 expression, demographic, clinicopathologic, and risk parameters were analyzed by Chi-square, Fisher's exact tests, and multivariate logistic regression. Results: PD-L1 expression was detected in 22 out of 85 cases of OSCC (25.9%). 16.5% of all cases were HPV 16/18-positive and 62.4% were p16-positive. Statistically, there were no significant associations between PD-L1 expression in OSCC and HPV16/18 DNA status, p16 expression, demographic and, clinicopathologic parameters or risk behaviors. Conclusion: Approximately one-fourth of OSCC cases were PD-L1-positive, suggesting candidacy for anti-PD-L1 immunotherapy. Furthermore, HPV infection and p16 expression were not involved with PD-L1 expression. Further clinical trials warrant the benefits of immunotherapy in patients with PD-L1-positive OSCC.

High Prevalence of Human Papillomavirus Type 18 in Oral Potentially Malignant Disorders in Thailand.

OBJECTIVES: The main objectives of this study were to investigate the detection rate of high-risk human papillomavirus types 16 and 18 (high-risk HPV16/18) in oral potentially malignant disorders (OPMDs) including oral leukoplakia (OL) and oral lichen planus (OLP) in a Thai population and their associations with demographic, risk habits, and clinicopathologic features. METHODS: Paraffin-embedded formalin-fixed specimens from 101 OL and 59 OLP patients with patients' demographic, risk habits, and clinicopathologic data were collected. Conventional qualitative polymerase chain reaction was used to detect high-risk HPV16/18 DNA. Associations between high-risk HPV type 16/18 and demographic, clinicopathologic, risk factors (tobacco and alcohol uses) of OPMDs were analysed by Chi-square or Fisher's exact test. The results with p value less than 0.05 were considered statistically significant. RESULTS: HPV16/18 DNA was found in both OL and OLP groups with the detection rate of 19.8% and 18.6%, respectively. Approximately 90% of high-risk HPV were HPV18 subtype. Additionally, in OL group, high-risk HPV was found more frequently in patients with moderate/severe dysplasia than that in mild dysplasia. Interestingly, in OLP group, high-risk HPV was only detected in atrophic/ulcerative subtypes. None of risk factors was associated with high-risk HPV. CONCLUSIONS: Approximately 19% of OPMDs were HPV16/18-positive. HPV18 DNA was predominantly detected in both OL and OLP patients (90%). Additionally, the detection rate of high-risk HPV was higher in more severe dysplastic cases of OL and more clinically severe cases of OLP.

Human Papillomavirus 16 and 18 Infection in Oral Cancer in Thailand: A Multicenter Study.

OBJECTIVES: To identify the prevalence of high-risk human papillomavirus (HPV) genotypes 16 and 18 among patients with oral squamous cell carcinoma (OSCC) in Thailand and investigate the associations of p16 expression and HPV16/18 with the demographic, clinicopathologic, and risk parameters. MATERIALS AND METHODS: A total of 403 formalin-fixed paraffin-embedded OSCC specimens from four centers in four regions were obtained. p16 expression was evaluated by immunohistochemistry. The detection of HPV16/18 DNA was performed by polymerase chain reaction.  Results: Of all, 172 specimens (42.7%) were presented with amplifiable extracted DNA. Among these, 62.8% were positive for p16, 8.1% were positive for HPV16/18, and 5.8% were positive for both methods. Of all HPV-positive specimens, HPV18 was detected in 57.1%; HPV16 in 14.3%; and HPV16 and 18 (co-infection) in 28.6%. The prevalence of HPV16/18 varied between centers, with the highest rate in the northern center (20.0%). There was no significant correlation between p16 expression and HPV16/18. There were no significant associations of p16 expression and/or HPV16/18 with all variables. CONCLUSIONS: The prevalence of HPV16/18 infection in OSCC geographically varied in Thailand, with the highest rate in the northern region. Poor correlation between p16 and HPV16/18 suggests p16 not be used as a surrogate marker for HPV-positive OSCC.
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Effect of coenzyme Q10 on mitochondrial respiratory proteins in trigeminal neuralgia.

Trigeminal neuralgia (TN) is the neuropathic pain. Mitochondrial dysfunction, increased oxidative stress, and inflammation demonstrated in chronic pain. Carbamazepine (CBZ) is the first-line drug for TN, however, it is still insufficient. Coenzyme Q10 (CoQ10) has been used as the additional supplement for pain therapy. Nonetheless, mitochondrial respiratory proteins, oxidative stress, and inflammation in TN, and the add-on effects of CoQ10 on those defects have never been investigated. CBZ-treated TN-patients, naïve TN-patients, and control subjects were included. CBZ-treated TN-patients were randomised into two subgroups, received either CoQ10 or placebo for 2 months. Pain levels were evaluated, and peripheral blood mononuclear cells were isolated to determine the oxidative stress, mitochondrial oxidative phosphorylation (OXPHOS), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and cytokines including TNF-α, IL-1ß and IL-18 mRNA expression. Pain scales, oxidative stress, and OXPHOS levels were greater in naïve TN-patients than control, whereas the cytokine profiles were unchanged. Although pain scales were lower in CBZ-treated TN-patients than in naïve TN-patients, oxidative stress, OXPHOS, and cytokine expression profiles were not different. PGC-1α levels found to be increased in CBZ-treated TN patients when compared with the naïve group. CoQ10 supplement in CBZ-treated TN patients reduced pain scale and oxidative stress and increased antioxidants levels when compared with placebo group. However, OXPHOS, PGC-1α, and cytokines were not different between groups. These findings suggest that increased oxidative stress could be potentially involved in the pathogenesis of TN. CoQ10 supplements can reduce oxidative stress, leading to more effective pain reduction in TN patients being treated with CBZ.

Association between hepatitis C infection in Thai patients with oral lichen planus: A case-control study.

AIM: The aim of the present study was to investigate the prevalence of hepatitis C virus (HCV) infection and evaluate liver enzyme levels in patients from upper northern Thailand with oral lichen planus (OLP). METHODS: A case-control study of 101 patients with OLP and 101 patients without OLP was conducted. Peripheral blood was taken from each patient and screened for anti-HCV antibody using immunochromatography. Positive samples were further confirmed using chemiluminescent microparticle immunoassay (CMIA) and reverse transcription-polymerase chain reaction. In addition, liver enzyme levels, alanine transaminase, aspartate transaminase, and alkaline phosphatase were evaluated using spectrophotometry. RESULTS: Immunochromatography and CMIA revealed that nine patients with OLP (8.9%) were positive for anti-HCV antibodies, whereas only one patient without OLP was HCV positive (odds ratio = 9.78). All patients who were HCV positive had significantly higher liver enzyme levels than patients who were HCV negative. CONCLUSIONS: The results of the present study indicated that OLP in certain patients was significantly associated with HCV. This could warrant screening for HCV-infected patients with OLP in Thailand.

p16 - a Possible Surrogate Marker for High-Risk Human Papillomaviruses in Oral Cancer?

BACKGROUND: High-risk human papillomaviruses (HR-HPV), particularly types 16 and 18, have been found to play an important role in head and neck cancer, including oropharyngeal squamous cell carcinoma (OPSCC) and oral squamous cell carcinoma (OSCC). p16, a cell cycle inhibitor, has been postulated as a surrogate marker for HR-HPV, since p16 is aberrantly overexpressed in such lesions, especially in HR-HPV-positive OPSCC. However, p16 as a surrogate marker for HR-HPV infection in cancers of the oral cavity remains controversial. OBJECTIVE: The objectives of the study were to investigate the expression of p16 and the presence of HR-HPV in OSCC and oral verrucous carcinoma (VC) and to determine if p16 could be used as a surrogate marker for HR-HPV. MATERIALS AND METHODS: Forty one formalin-fixed, paraffin-embedded tissues of OSCC (n=37) or VC (n=4) with clinical and histopathologic data of each case were collected. Expression of p16 was determined by immunohistochemistry, focusing on both staining intensity and numbers of positive cells. The presence of HPV types 16 and 18 was detected by polymerase chain reaction (PCR). Descriptive statistics were employed to describe the demographic, clinical, and histopathologic parameters. Associations between p16 overexpression, HR-HPV and all variables were determined by Fisher's exact test, odds ratios (ORs) and corresponding 95% confidence intervals (CIs). In addition, the use of p16 as a surrogate marker for HR-HPV was analyzed by sensitivity and specificity tests. RESULTS: p16 was overexpressed in 8/37 cases (21.6%) of OSCC and 2/4 cases (50%) of VC. HPV-16 was detected in 4/34 OSCC cases (11.8%) and HPV-18 was detected in 1/34 OSCC cases (2.9%). Co-infection of HPV-16/18 was detected in 1/4 VC cases (25%). Both p16 overexpression and HR-HPV were significantly associated with young patients with both OSCC and VC (<0.05, OR 20, 95% CI 1.9-211.8; <0.05, OR 23.3, 95% CI 2.4-229.7, respectively). p16 was able to predict the presence of HPV-16/18 in OSCC with 40% sensitivity and 79.3% specificity and in VC with 100% sensitivity and 66.7% specificity, respectively. CONCLUSIONS: p16 overexpression was found in 24.4% of both OSCC and VC. HR-HPV, regardless of type, was detected in 15.8% in cases of OSCC and VC combined. The results of sensitivity and specificity tests suggest that p16 can be used as a surrogate marker for HR-HPV in OSCC and VC.

Increased cyclooxygenase 2 expression in association with oral lichen planus severity.

BACKGROUND/PURPOSE: Although some studies have shown induction of cyclooxygenase 2 (COX-2) in oral lichen planus (OLP), an association between COX-2 upregulation and OLP clinical severity has not been investigated. Therefore, we aimed to compare COX-2 expression in OLP with that in normal oral tissues, and to determine correlations between COX-2 expression and both clinical criteria and visual analog scale (VAS) scores. MATERIALS AND METHODS: COX-2 expression was studied in 25 OLP and 13 normal oral tissues by immunohistochemistry. Both clinical criteria and VAS scores were used to evaluate the clinical severity of OLP. The differences in COX-2 expression between OLP and normal tissues, and the correlations between COX-2 expression and clinical severity were determined by the nonparametric statistical tests. RESULTS: COX-2 expression was significantly increased in OLP epithelium when compared with normal epithelium (P < 0.001), and intense COX-2 staining in inflammatory infiltrates was observed in the OLP lamina propria. COX-2 expression in OLP epithelium and inflammatory infiltrates was significantly correlated with the clinical criteria score (r = 0.428, P = 0.007, and r = 0.681, P < 0.001, respectively), whereas a significant correlation with the VAS score was observed only in OLP inflammatory infiltrates (r = 0.605, P < 0.001). CONCLUSION: Enhanced COX-2 expression in both OLP epithelium and inflammatory infiltrates correlates well with the clinical severity. An association between VAS score and COX-2 expression in OLP inflammatory infiltrates suggests an important role of additional COX-2 expression from inflammation in causing pain in OLP patients.

Diagnostic performance of cone-beam computed tomography on detection of mechanically-created artificial secondary caries.

PURPOSE: The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. MATERIALS AND METHODS: One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve (A(z)) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). RESULTS: The mean A(z) values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest A(z) value. CONCLUSION: Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.

A multicenter study of oral lichen planus in Thai patients.

AIM: Oral lichen planus is an oral mucosal disease that affects middle-aged patients. The characteristics of oral lichen planus in Thai patients from a multicenter were studied. METHODS: Data of 533 patients from the oral medicine clinics at Chulalongkorn and Mahidol (central Thailand), Chiang Mai (northern Thailand), and Khon Kaen (northeastern Thailand) universities during 2002-2007 were analyzed. The diagnosis of patients with oral lichen planus was clinically and/or histopathologically confirmed. RESULTS: There was a greater number of female patients than males (4:1). There were significant differences in age, sex, and some systemic diseases among the oral lichen planus patients from the three centers. Burning sensation was the most common symptom (72.9%), followed by pain (26.5%), roughness (6.4%), and then no other symptoms (7.9%). The most common site of lesions was found at the buccal mucosa (87.1%). Atrophic oral lichen planus was common in Thai patients. There were significant differences in the types of oral lichen planus, including reticular, atrophic, and ulcerative oral lichen planus among these patients from the three centers (P = 0.000). Nine cases (1.7%) showed dysplasia, but one case (0.2%) developed squamous cell carcinoma. CONCLUSION: Patients with oral lichen planus from the central, northern, and northeastern parts of Thailand presented with distinct characteristics. The malignant transformation of oral lichen planus was low in Thai patients.

Oral colonization of Candida species in perinatally HIV-infected children in northern Thailand.

Human immunodeficiency virus (HIV) infection remains a serious problem in northern Thailand. A high prevalence of perinatally HIV-infected children with oral candidiasis has been observed in the region. The objective of this study was to determine oral colonization of Candida spp. in children with perinatal HIV infection. Samples were collected by oral rinse or oral swab from 40 HIV-infected children and from 15 HIV-negative children as a control group. Yeasts recovered in culture were identified and quantified. The mean ages of HIV-infected children and HIV-negative children were 5.5 years (SD = 3.5) and 2.9 years (SD = 2.0) respectively. Eighteen HIV-infected children (45%) had clinical symptoms of oral candidiasis while none of the HIV-negative children had any such symptoms. By culture technique, yeasts were isolated from 28/40 (70%) of the HIV-infected children and 6/15 (40%) of the HIV-negative children. C. albicans was the most common species recovered from HIV-infected and HIV-negative children. Statistically, HIV infection was significantly associated with Candida spp. detection (P-value = 0.04). In contrast, the association between HIV infection and asymptomatic oral carriage of Candida spp. was not significant (P-value = 0.74). These findings demonstrate that oral colonization of Candida spp. is prevalent in HIV-infected children and suggest that prevention and treatment of oral candidiasis is needed for these children.

Co-expression of p53 and Ki67 and lack of EBV expression in oral squamous cell carcinoma.

BACKGROUND: The objectives of the study were to determine the association between Epstein-Barr virus (EBV) and oral squamous cell carcinoma (OSCC), to compare the expression of p53 and Ki67 between normal oral mucosa, oral hyperkeratosis, oral pre-malignant dysplasia, and OSCC, and to determine the correlation between the expression of p53 and Ki67 in OSCC. METHODS: The expression of EBV mRNA was studied by in situ hybridization technique in 24 cases of OSCC, and the expression of p53 and Ki67 was investigated by immunohistochemical method in 19 cases of OSCC, 7 cases of oral pre-malignant dysplasia, 6 cases of oral hyperkeratosis, and 5 cases of normal oral epithelium. RESULTS: None of OSCC cases expressed EBV-encoded RNA (EBER) transcripts. The labeling indices (LI) of p53- and Ki67-positive cells were significantly higher in OSCC than in oral pre-malignant dysplasia, oral hyperkeratosis, and normal oral mucosa (P < 0.05). A significant correlation between the LI of p53- and Ki67-positive cells was observed in OSCC (r = 0.6; P = 0.01). CONCLUSIONS: These findings suggested that the co-expression of p53 and Ki67 may play roles in carcinogenesis of OSCC and p53 overexpression may promote cell proliferation in OSCC. Furthermore, EBV does not appear to be a risk factor for OSCC particularly in the population of northern Thailand.

Detection of Helicobacter pylori in recurrent aphthous ulceration by nested PCR.

Recurrent aphthous ulceration (RAU) is the most common lesion of the oral mucosa. Although many factors have been postulated as etiological factors for RAU, the role of Helicobacter pylori as a causative agent of RAU remains controversial. We therefore investigated the association of H. pylori and RAU by a highly sensitive technique, nested polymerase chain reaction (PCR), in 22 patients with RAU with ages ranging from 12-36 years. Samples were brushed from the lesions and the dorsum of the tongue of each patient. In addition, samples from the dorsum of the tongue of 15 normal individuals with ages ranging from 13-40 years were used as controls. The results showed that only one sample from a lesion (4.5%) and one sample from the tongue (4.5%) of two different patients with RAU were positive for H. pylori. In the control group, 3 samples (20%) were positive for H. pylori. These findings suggest that H. pylori does not play a role in the pathogenesis of RAU and the dorsum of the tongue may be a reservoir of H. pylori in some individuals.

Oral white sponge naevus: case report.

The clinical appearances of white sponge naevus may mimic other oral white lesions, including premalignant leukoplakia but, unlike leukoplakia, white sponge naevus does not have malignant potential. This article presents a case of an irregular white lesion on the oral mucosa with findings suggestive of white sponge naevus.

Increase of mast cells and tumor angiogenesis in oral squamous cell carcinoma.

BACKGROUND: Although mast cells (MCs) have been implicated in promoting angiogenesis in some malignant tumors, especially of the aerodigestive tract, little is known in oral squamous cell carcinoma (SCC). METHODS: A retrospective study was conducted to elaborate upon the correlation between MCs and tumor angiogenesis in 26 cases of oral SCC, six cases of oral pre-malignant dysplasia, 10 cases of oral hyperkeratosis, and six cases of normal oral mucosa by means of immunohistochemical technique. RESULTS: The MCs in all lesions and normal oral mucosa strongly expressed tryptase. The densities of MCs and microvessels appeared to increase with disease progression. The MC and microvascular counts were significantly higher in oral SCC than in hyperkeratosis and normal oral mucosa (P < 0.05). A significant correlation between MC and microvascular densities was observed in oral SCC (r = 0.5; P = 0.012). CONCLUSIONS: These findings suggest that MCs may upregulate tumor angiogenesis in oral SCC, perhaps via MC tryptase.