Isabel Poiares Baptista

Genetic gains and losses in oral squamous cell carcinoma: impact on clinical management

PurposeThe identification of genetic markers associated with oral cancer is considered essential to improve the diagnosis, prognosis, early tumor and relapse detection and, ultimately, to delineate individualized therapeutic approaches. Here, we aimed at identifying such markers.MethodsMultiplex Ligation-dependent Probe Amplification (MLPA) analyses encompassing 133 cancer-related genes were performed on a panel of primary oral tumor samples and its corresponding resection margins (macroscopically tumor-free tissue) allowing, in both types of tissue, the detection of a wide arrange of copy number imbalances on various human chromosomes.ResultsWe found that in tumor tissue, from the 133 cancer-related genes included in this study, those that most frequently exhibited copy number gains were located on chromosomal arms 3q, 6p, 8q, 11q, 16p, 16q, 17p, 17q and 19q, whereas those most frequently exhibiting copy number losses were located on chromosomal arms 2q, 3p, 4q, 5q, 8p, 9p, 11q and 18q. Several imbalances were highlighted, i.e., losses of ERBB4, CTNNB1, NFKB1, IL2, IL12B, TUSC3, CDKN2A, CASP1, and gains of MME, BCL6, VEGF, PTK2, PTP4A3, RNF139, CCND1, FGF3, CTTN, MVP, CDH1, BRCA1, CDKN2D, BAX, as well as exon 4 of TP53. Comparisons between tumor and matched macroscopically tumor-free tissues allowed us to build a logistic regression model to predict the tissue type (benign versus malignant). In this model, the TUSC3 gene showed statistical significance, indicating that loss of this gene may serve as a good indicator of malignancy.ConclusionsOur results point towards relevance of the above mentioned cancer-related genes as putative genetic markers for oral cancer. For practical clinical purposes, these genetic markers should be validated in additional studies.

Genetic imbalances detected by multiplex ligation-dependent probe amplification in a cohort of patients with oral squamous cell carcinoma—the first step towards clinical personalized medicine

Oral tumors are a growing health problem worldwide; thus, it is mandatory to establish genetic markers in order to improve diagnosis and early detection of tumors, control relapses and, ultimately, delineate individualized therapies. This study was the first to evaluate and discuss the clinical applicability of a multiplex ligation-dependent probe amplification (MLPA) probe panel directed to head and neck cancer. Thirty primary oral squamous cell tumors were analyzed using the P428 MLPA probe panel. We detected genetic imbalances in 26 patients and observed a consistent pattern of distribution of genetic alterations in terms of losses and gains for some chromosomes, particularly for chromosomes 3, 8, and 11. Regarding the latter, some specific genes were highlighted due to frequent losses of genetic material—RARB, FHIT, CSMD1, GATA4, and MTUS1—and others due to gains—MCCC1, MYC, WISP1, PTK2, CCND1, FGF4, FADD, and CTTN. We also verified that the gains of MYC and WISP1 genes seem to suggest higher propensity of tumors localized in the floor of the mouth. This study proved the value of this MLPA probe panel for a first-tier analysis of oral tumors. The probemix was developed to include target regions that have been already shown to be of diagnostic/prognostic relevance for oral tumors. Furthermore, this study emphasized several of those specific genetic targets, suggesting its importance to oral tumor development, to predict patients’ outcomes, and also to guide the development of novel molecular therapies.

WT1, MSH6, GATA5 and PAX5 as epigenetic oral squamous cell carcinoma biomarkers - a short report.

PurposeOral squamous cell carcinoma (OSCC) is a frequently occurring aggressive malignancy with a heterogeneous clinical behavior. Based on the paucity of specific early diagnostic and prognostic biomarkers, which hampers the appropriate treatment and, ultimately the development of novel targeted therapies, we aimed at identifying such biomarkers through a genetic and epigenetic analysis of these tumors.Methods93 primary OSCCs were subjected to DNA copy number alteration (CNA) and methylation status analyses using methylation-specific multiplex ligation-dependent probe amplification (MS-MPLA). The genetic and epigenetic OSCC profiles obtained were associated with the patients’ clinic-pathological features.ResultsWe found that WT1 gene promoter methylation is a predictor of a better prognosis and that MSH6 and GATA5 gene promoter methylation serve as predictors of a worse prognosis. GATA5 gene promoter methylation was found to be significantly associated with a shorter survival rate. In addition, we found that PAX5 gene promoter methylation was significantly associated with tongue tumors. To the best of our knowledge, this is the first study that highlights this specific set of genes as epigenetic diagnostic and prognostic biomarkers in OSCC.ConclusionsOur data highlight the importance of epigenetically assessing OSCCs to identify key genes that may serve as diagnostic and prognostic biomarkers and, potentially, as candidate therapeutic targets.

The dog as a model for peri-implantitis: A review.

ABSTRACT Objective: To analyze the current available experimental canine models for peri-implantitis. Material and Methods: Electronic databases of the PubMed, EBSCOhost, and Cochrane Library were searched for dog studies on peri-implantitis induction methodology, until October 31, 2012. The eligibility of the studies for this review was based on the screening of two independent reviewers. Results: After screening, 50 publications were eligible for review. The most used animal model was the Beagle (n = 23). The bilateral mandible four premolar were the most extracted group of teeth (n = 20) and the majority of the studies had the placement of six implants in the jaw with only five (n = 5) of them reporting on interimplant distance. All publications reported peri-implantitis induction using ligature during a variable period of time and with a subsequent heterogeneous loss of peri-implant bone. The ligature placement and maintenance around the implant varied greatly between the publications. The constant use of ligatures, sometimes traumatically forced to the peri-implant sulcus, may influence the degree of bone loss during canine experimental peri-implantitis overlapping the contribution of implant surface to the onset and development of this pathology. Conclusions: A great heterogeneity exists among the studies reporting on the induction of peri-implantitis in canine. Experimental peri-implantitis model has suffered a change through the last years, from an exclusive ligature-induced to a ligature-induced and nonligature induced progression, thus approaching the natural occurrence of this pathology. The ideal canine peri-implantitis induction model would be a naturally occurring peri-implanititis induction without the action of any ligature.

Validation of a dental image‐analyzer tool to measure the radiographic defect angle of the intrabony defect in periodontitis patients

BACKGROUND AND OBJECTIVE   A report describing the software Dental Image Analyzer (DIA) was published in this journal in 2009. A new function - measurement of the periodontal intrabony defect angle - was added to the software in 2010. The purpose of this study was to investigate whether measurements of the radiographic intrabony defect angle using digital radiographs and the newly developed DIA tool were comparable with measurements obtained using the conventional protractor method. MATERIAL AND METHODS   The baseline radiographic defect angle of intrabony defects was measured conventionally, using a protractor, in 60 selected teeth from 47 patients and then digitally using the newly developed DIA tool. The measurements were made independently by four experienced dentists. The radiographic defect angle of intrabony defects was measured after the three anatomical landmarks were identified, namely the cemento-enamel junction, the top of the crest and the bottom of the defect. RESULTS   Both methods showed a high interexaminer reliability for measurements of the radiographic defect angle of intrabony defects (intraclass correlation coefficient > 0.97). Moreover, both methods showed high reliability (intraclass correlation coefficient > 0.96). On the other hand, the new DIA tool, compared with the conventional method, exhibited high sensitivity (0.92) and high specificity (0.91) in selecting defects of ≥ 37° or < 37°. Analysis of the time taken for measurements revealed significant differences between the two methods, with the protractor method being more time consuming. CONCLUSIONS   This study provided evidence for the lack of a significant difference between the conventional method and the DIA tool for radiographic measurement of intrabony defects. However, digital analysis was significantly faster.

# 44. Minociclina e clorexidina na descontaminação química de implantes: estudo piloto

Objetivos:Analisar a influencia da pigmentacao da zirconia e do condicionamento de superficie na rugosidade, molhabilidade e transformacao de fase da zirconia. Materiais e metodos: Foram fabricados cinquenta discos (10 x 0,9mm) de zirconia estabilizada com itria (Zerion, Straumann). Dez grupos experimentais foram constituidos a partir das diferentes combinacoes possiveis entre pigmentacao [1sem pigmento; 2com pigmento a cor A3] e condicionamento de superficie [1sem condicionamento (controlo); 2jato de Al2O3 de 110 m; 3broca de diamante de grao grosso; 4acido quente; 5acido hidrofluoridrico). A rugosidade (Rq) foi avaliada recorrendo a um rugosimetro. A molhabilidade foi calculada pela medicao do ângulo de contacto utilizando o Sessile Drop Method. A transformacao da fase foi determinada pelo metodo da Difracao de Raio X (DRX). Os dados obtidos foram analisados com testes estatisticos nao parametricos segundo o metodo de Kruskall-Wallis e Mann-Whitney (alfa = 0,05). Resultados: Os valores de Rq variaram entre 1,11 (sem pigmento com acido quente) e 2,15 (sem pigmento com broca). A pigmentacao da zirconia nao influenciou de forma estatisticamente significativa o Rq (p=0,541). Apesar do condicionamento de superficie ter influenciado de forma estatisticamente muito significativa (p =0,05). A molhabilidade variou entre 53,08◦ (pigmento A3 com Al2O3) e 98,64◦ (pigmento A3 sem condicionamento). Nao se observaram diferencas estatisticamente significativas (p=0,061) entre a molhabilidade da zirconia com e sem pigmento, no entanto, esta propriedade da zirconia foi influenciada pelo condicionamento de superficie (p <0,001). Tanto o jato de Al2O3 ou como a broca de diamante tornaram a superficiemais hidrofila que o acido quente e a superficie sem condicionamento (p<0,05). No entanto, o condicionamento da superficie com Al2O3 e com broca conduziram a um maior aumento da percentagem de fase monoclinica na zirconia, comparativamente aos outros tratamentos de superficie. Conclusoes: A pigmentacao nao teve qualquer influencia nos tres testes efetuados. Os condicionamentos mecânicos que aumentaram a rugosidade e a hidrofilia da superficie da zirconia foram tambem os que mais aumentaram a percentagem de fase monoclinica.

Novel Nanocrystalline Hydroxyapatite for BoneRegeneration

Novel Nanocrystalline Hydroxyapatite for Bone Regeneration Maxillofacial bone defects resulting from disease or trauma are one main problem for modern dentistry. Regenerative treatments aim to provide the lost initial conditions improving the patient’s life quality. Bone graft substitutes have been regarded as suitable alternatives to obtain regenerative outcomes. Among these, synthetic hydroxyapatites are successfully evaluated bone substitutes, both in pre-clinical as well as clinical studies. The aim of this study is to evaluate the bone regenerative potential of a nanocrystalline hydroxyapatite (nHA), in a delayed healing cranial rabbit model.