Vivian Petersen Wagner

Influence of different energy densities of laser phototherapy on oral wound healing

Abstract. The aim of the present prospective study was to evaluate the impact of laser phototherapy (LPT) on the healing of oral ulcers. Different power densities were used on oral wounds in Wistar rats (n=72) randomly divided into three groups: control (0  J/cm2), 4  J/cm2 laser, and 20  J/cm2 laser. Ulcers (3 mm in diameter) were made on the dorsum of the tongue with a punch. Irradiation with an indium-gallium-aluminum-phosphide laser (660 nm; output power: 40 mW; spot size: 0.04  cm2) was performed once a day in close contact with the ulcer for 14 consecutive days. A statistically significant acceleration in healing time was found with wounds treated with 4  J/cm2 LPT. Moreover, striking differences were found in the ulcer area, healing percentage, degree of reepithelialization, and collagen deposition. The most significant changes occurred after 5 days of irradiation. Based on the conditions employed in the present study, LPT is capable of accelerating the oral mucosa wound-healing process. Moreover, faster and more organized reepithelialization and tissue healing of the oral mucosa were achieved with an energy density of 4  J/cm2 in comparison to 20  J/cm2.

Hypoacetylation of acetyl‐histone H3 (H3K9ac) as marker of poor prognosis in oral cancer

Epigenetics refers to changes in cell characteristics that occur independently of modifications to the DNA sequence. Oral carcinogenesis is influenced by modifications in epigenetic mechanisms, including changes in histones, which are proteins that support chromatin remodelling for the dynamic regulation of gene expression and silencing. The dysregulation of histone acetylation can lead to the uncontrolled activity of different genes, thereby triggering events associated with malignant transformation. The aim of this study was to analyse the expression of acetyl‐histone H3 at lys9 (H3K9ac) in oral leucoplakia (OL) and oral squamous cell carcinoma (OSCC) in addition to its association with cell proliferation, epithelial–mesenchymal transition (EMT) and clinical‐pathological findings.

VEGFR1 and VEGFR2 in lip carcinogenesis and its association with microvessel density

The aim of the present study was to determine the role of vascular endothelial growth factor receptors (VEGFR1 and VEGFR2) in lip carcinogenesis, to investigate correlations between these markers with microvessel density (MVD) and clinicopathological aspects. Medical records from 27 cases of actinic cheilitis (AC) and 46 cases of lower lip squamous cell carcinoma (LLSCC) were analysed and submitted to immunohistochemistry. VEGFR1- and VEGFR2-immunostained sections were analysed based on percentage of positive epithelial and inflammatory cells, while CD31 was submitted to quantitative analysis to determine MVD. Different patterns of VGFR1 and VEGFR2 expression were observed between AC and LLSCC. VEGFR1 expression in epithelial and inflammatory cells and VEGFR2 expression in epithelial cells were higher in AC compared to LLSCC (p < 0.05). VEGFR1 expression in epithelial cells was higher in LLSCC compared to AC (p < 0.001). Expression of both receptors was not associated to MVD or clinicopathological aspects. A direct correlation was found between epithelial VEGFR1 and VEGFR2 expression (p = 0.02) and between VEGFR2 epithelial and inflammatory expression (p < 0.001). Our findings indicate that activation of VEGFR1 and VEGFR2 in epithelial and inflammatory cells appears to be an early event in lip carcinogenesis.

Effects of Copaiba Oil Topical Administration on Oral Wound Healing

The effects of topical copaiba oil extract and topical corticosteroid were assessed on oral wound healing in an in vivo model using 96 male Wistar rats. Traumatic ulcers were caused in the dorsum of the tongue using a 3‐mm punch tool. The animals were divided into: Control; Corticosteroid; Placebo and Copaiba oil Group. The animals received two daily applications of the products. The control group received only daily handling. Six rats in each group were euthanized at days 3, 5, 10 and 14. The animals were monitored daily to determine wound status. The weigh was assessed at day 0 and euthanasia day. The percentage of repair was calculated, and histopathological aspects were analyzed. The Kruskal–Wallis test was used to compare the results between groups and times of evaluation. Closing time was assessed through the log‐rank test. The corticosteroid group lost more weight at days 10 and 14 than the control group (p < 0.05). Moreover, the healing time of corticosteroid group was longer than the control group (p = 0.007). No differences were observed between the copaiba oil group and the control group. We concluded that topical copaiba oil, in spite of being safe, did not accelerate the process of oral wound healing. Copyright

Overexpression of MutSα Complex Proteins Predicts Poor Prognosis in Oral Squamous Cell Carcinoma.

AbstractThe DNA mismatch repair (MMR) system is responsible for the detection and correction of errors created during DNA replication, thereby avoiding the incorporation of mutations in dividing cells. The prognostic value of alterations in MMR system has not previously been analyzed in oral squamous cell carcinoma (OSCC).The study comprised 115 cases of OSCC diagnosed between 1996 and 2010. The specimens collected were constructed into tissue microarray blocks. Immunohistochemical staining for MutS&agr; complex proteins hMSH2 and hMSH6 was performed. The slides were subsequently scanned into high-resolution images, and nuclear staining of hMSH2 and hMSH6 was analyzed using the Nuclear V9 algorithm. Univariable and multivariable Cox proportional hazard regression models were performed to evaluate the prognostic value of hMSH2 and hMSH6 in OSCC.All cases in the present cohort were positive for hMSH2 and hMSH6 and a direct correlation was found between the expression of the proteins (P < 0.05). The mean number of positive cells for hMSH2 and hMSH6 was 64.44 ± 15.21 and 31.46 ± 22.38, respectively. These values were used as cutoff points to determine high protein expression. Cases with high expression of both proteins simultaneously were classified as having high MutS&agr; complex expression. In the multivariable analysis, high expression of the MutS&agr; complex was an independent prognostic factor for poor overall survival (hazard ratio: 2.75, P = 0.02).This study provides a first insight of the prognostic value of alterations in MMR system in OSCC. We found that MutS&agr; complex may constitute a molecular marker for the poor prognosis of OSCC.

Histogenesis of keratoacanthoma: Histochemical and immunohistochemical study

OBJECTIVES Keratoacanthoma (KA), a keratinocytic neoplasm, is associated with sun exposure and is often found in the head and neck area, including the lip. KA is thought to arise from hair follicle cells, but its origin is largely unknown. Keratins (Ks) and histochemical stains are of great value to characterize and identify normal and neoplastic cells. The objective of this study is to analyze a panel of Ks and periodic acid-Schiff (PAS) staining on KA. STUDY DESIGN Using KA biopsies from the lips and normal skin samples, we performed immunohistochemical and histochemical profiling to determine which biomarkers are conserved between tumors and normal tissues. RESULTS The normal hair follicle has multiple well-defined compartments. The outer root sheath (ORS) cells presented K6 and K14 and were also PAS positive. In addition, the infundibulum cells showed positive labeling to K10. Hair cortex keratin was observed in the cortical and precortical cells. Interestingly, KA tumor cells were positive for PAS, K6, K10, and K14 but not to hair cortex keratin. Lip and skin epithelium were negative for PAS and K6. CONCLUSIONS Our results indicate that KA of the lip is derived from ORS cells, particularly those cells associated with the upper ORS.

A 10-year analysis of the oral squamous cell carcinoma profile in patients from public health centers in Uruguay

The aim of this study was to evaluate the demographic, clinical, and therapeutic characteristics and predictive factors of poor prognosis in patients with primary oral squamous cell carcinoma (OSCC) in Uruguay. Medical records of patients with the diagnosis of primary OSCC treated between 2000 and 2010 in Uruguayan public hospitals were selected. Data on demographic characteristics, risk factors, clinical features, treatment, and outcome were collected. Associations of independent variables with outcomes were assessed using Pearson chi-squared and Fishers tests. Of 200 patients with OSCC, 79.4% were men (3.8:1 male:female ratio), with a mean age of 60.75 ± 11.26 years. Tobacco and alcohol consumption were reported by 85.3% and 63.5% of patients, respectively. The most commonly affected location was the tongue (42.5%), with lesions exhibiting ulcerous aspects in 87.9% of cases and pain at the time of diagnosis in 70.4% of cases. One hundred sixty-one (82.1%) patients had advanced-stage (III/IV) OSCC. Surgery was the most common treatment option, and the overall 5-year survival rate was 58.5%. Univariate analysis showed that the predictors of poor prognosis were clinical aspect, size, regional metastasis, clinical stage, and treatment. In Uruguay, OSCC is diagnosed late, which is associated with a low survival rate. Educational and preventive measures and investment to improve early diagnosis should be undertaken.

Uncovering the role of brain-derived neurotrophic factor/tyrosine kinase receptor B signaling in head and neck malignancies

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors that was first known as responsible for sustain the growth, function, and plasticity of neural cells. BDNF exerts its effects by binding to the tyrosine kinase receptor B (TrkB). The BDNF/TrkB axis has been reported to be overexpressed in several neurogenic and non-neurogenic tumors. Its higher expression was associated with a poor prognosis to patients affected by different human malignancies, tumor growth, invasion, and metastasis; epithelial-mesenchymal transition and resistance to chemotherapy. BDNF/TrkB represent promising targets to the development of novel anticancer therapies. Some clinical trials are currently evaluating the efficacy of Trk protein-target drugs in different types of solid tumors. To date, few groups have evaluated the DNF/TrkB pathway in head and neck malignancies. The aims of this study were to review the literature concerning the role of BDNF/TrkB activation in head and neck squamous cell carcinoma and malignant salivary gland tumors and to discuss future perspectives of BDNF/TrkB-target therapy.

Immunoprofile of c-MET/PI3K signaling in human salivary gland tumors

OBJECTIVE The aim of this study was to analyze the expression pattern of proteins in the HGF/c-MET/PI3K signaling pathway in salivary gland tumors (SGTs) and to correlate the findings with the proliferative index and clinical parameters. STUDY DESIGN We assembled tissue microarrays (TMAs) of 108 cases of SGTs, including 69 cases of pleomorphic adenoma (PA), 24 cases of adenoid cystic carcinoma (AdCC), and 15 cases of mucoepidermoid carcinoma (MEC). An immunohistochemical analysis of hepatocyte growth factor (HGF), MET phosphorylation (p-MET), protein kinase B (AKT) phosphorylation (p-AKT), and Ki-67 proteins was performed. RESULTS Benign and malignant SGTs presented similar scores of HGF-positive cells (P = .36), whereas, malignant SGTs exhibited higher levels of p-MET (P = .001) and p-AKT (P = .001) than benign SGTs. No correlation of HGF, p-MET, or p-AKT expression was observed with clinical parameters. PA had a lower proliferative index than either AdCC (P = .001) or MEC (P = .001). CONCLUSIONS The salivary gland carcinomas exhibited increased activation of the HGF pathway, as evidenced by the phosphorylation of the MET receptor, and increased activation of the PI3K pathway, as indicated by p-AKT. These data suggest that the HGF/c-MET/PI3K signaling pathway is active in SGTs, especially in malignant neoplasms.

Histones Acetylation and Cancer Stem Cells (CSCs)

Chromatin decondensation is a key mechanism that guarantees gene transcription and repair of the genome, regulated mainly by the acetylation of histones. Emerging evidence has pointed out to histones as a new controlling mechanism of stem cell maintenance and fate. In this chapter, we will focus on the methods used to enrich tumor cell lines for cancer stem cells, and in the methods to identify the status of the histone acetylation in cancer cells and stem cells using immunofluorescence, invasion, and adhesion assays and identification of nuclear size.