Analyse de la distribution des génotypes du virus du papillome humain dans les néoplasies anogénitales et de la tête et du cou en Afrique comparativement au reste du monde

Le virus du papillome humain (HPV) est l’infection sexuellement transmise la plus fréquente au monde. Plusieurs études ont établi son implication dans l’étiologie de pratiquement tous les cancers du col de l’utérus, une maladie qui constitue un problème de santé majeur dans les pays pauvres. Le HPV est également responsable de 90% des cancers de l’anus, 40-50% des cancers du pénis, de la vulve et du vagin, et 30% des cancers de la tête et du cou. L’objectif général de cette thèse est de combler les lacunes relatives aux connaissances sur la distribution génotypique du HPV dans les lésions néoplasiques cervicales utérines et de la tête et du cou, plus particulièrement en Afrique. Les objectifs spécifiques sont les suivants: 1) analyser la distribution génotypique du HPV dans les cancers du col de l’utérus et faire une analyse comparative de cette distribution dans cinq pays africains en fonction de la prévalence du VIH; 2) évaluer la présence du HPV dans les cancers de la tête et du cou au Sénégal; 3) faire une revue de la littérature et une méta-analyse sur la distribution du HPV dans les cancers de la tête et du cou dans toutes les régions du monde. Pour le premier et le second objectifs, qui découlent d’un large projet international coordonné par l’Institut Catalan d’Oncologie pour l’Organisation Mondiale de la Santé (OMS), une étude transversale multicentrique a été menée au Mali et au Sénégal pour collecter des blocs de paraffine de patientes diagnostiquées entre 2001 et 2010 du cancer invasif du col et des cancers de la tête et du cou. Pour le troisième objectif, une revue exhaustive de la littérature a permis d’identifier tous les articles qui ont été publiés sur les cancers de la tête et du cou dans tous les pays du monde et d’effectuer une méta-analyse sur la prévalence de l’ADN du HPV selon le site du cancer et la région géographique. Notre analyse montre que les principaux types de HPV ciblés dans les vaccins prophylactiques (HPV16/18) représentent la majorité des types de HPV détectés dans le cancer invasif du col de l’utérus en Afrique subsaharienne. Par contre, le HPV45 vient au second rang dans certains pays d’Afrique, dont le Mali et le Sénégal. Nos données suggèrent également que le VIH aurait un rôle dans la contribution relative du HPV18 et HPV45 dans le développement du cancer du col de l’utérus. Au Sénégal, notre étude montre que la prévalence du HPV dans les cancers de la tête et du cou est très faible et ne semble pas jouer un rôle important dans l’oncogenèse. Finalement, la méta-analyse a mesuré la prévalence des HPV dans les cancers de la cavité orale, de l’oropharynx, du larynx et de l’hypopharynx, et confirme l’importante contribution relative du HPV16 dans ces cancers. Globalement, cette thèse permet de mieux comprendre l’impact potentiel des vaccins prophylactiques sur l’incidence des cancers associés au HPV.

Caracterizacion de nódulos tiroideos: concordancia entre estudio citopatologico y ecografia en la detección de nódulos malignos

: Los métodos imagenológicos para evaluar los nódulos tiroideos han sido motivo de estudio en las últimas décadas, especialmente la ecografía sobresale sobre las otras modalidades diagnósticas por su accesibilidad, portabilidad, y seguridad. A pesar de ello, las características ecográficas de cada nódulo han sido objeto de controversia en cuanto a su potencial detección de malignidad o benignidad. Se presenta un estudio de concordancia entre el estudio citopatológico y la ecografía para la caracterización nódulos tiroideos de naturaleza maligna y benigna, y su análisis de pruebas diagnósticas. Metodología: Se realizó un estudio descriptivo de concordancia con estudio de pruebas diagnósticas anidado. Se escogieron todos los pacientes con nódulos tiroideos a quienes se les realizó ecografía y estudio citopatológico de la lesión y se estudiaron los hallazgos ecográficos para evaluar su potencial diagnóstico para malignidad. Se incluyeron un total de 100 pacientes con nódulos tiroideos potencialmente malignos. La concordancia entre la ecografía en modo B y el estudio citopatológico fue moderada (índice kappa 0.55). La característica con mayor potencial para detectar malignidad fue la presencia de Microcalcificaciones (sensibilidad 75%, especificidad 92%).

Representaciones sociales de la medicina complementaria y alternativa (MCA) para el cáncer en estudiantes universitarios de carreras de ciencias de la salud

Se realizó un estudio cualitativo exploratorio con estudiantes de carreras de Ciencias de la Salud con el objetivo de comprender las representaciones sociales que tienen acerca de la Medicina Complementaria y Alternativa (MCA) para el cáncer. Se desarrollaron grupos focales y la información obtenida fue analizada a través del Análisis Temático e interpretada con base en la Teoría de las Representaciones Sociales. Se encontraron diversas representaciones sociales asociadas con la definición, los objetivos, los tratamientos, la eficacia, las fuentes de información y el origen de la MCA. En conclusión se evidenció una alta tendencia a la aceptación y a la manifestación de una actitud positiva, aunque ambivalente frente a la MCA, además de un desconocimiento por la diferenciación conceptual entre este tipo de Medicina y la Medicina Popular. La cultura y las creencias sociales predominan en las representaciones sociales que tienen los estudiantes de la MCA para el cáncer, pese a su formación académica.

Efeitos agudos do tratamento de radioterapia em doentes com carcinoma de cabeça e pescoço: IMRT vs RapidArc

A Radioterapia é parte integrante, standart, da abordagem multidisciplinar do tratamento de Carcinomas de Cabeça e Pescoço (CPP). A perceção e descrição dos efeitos provocados pelo tratamento ao nível dos tecidos normais é importante para avaliação clínica do doente, já que com o aparecimento de efeitos agudos severos/graves ao tratamento, este é interrompido, o que afetando diretamente a sobrevida do doente. Este estudo incidiu na avaliação de 6 semanas de tratamento de 46 doentes, contemplando a avaliação dos efeitos agudos do tratamento em cinco áreas anatómicas distintas: Pele, Mucosa, Glândulas Salivares, Faringe/Esófago e Laringe. Fundamentada nos critérios de classificação do Acute Radiation Morbidity Scoring Criteria da Radiation Therapy Oncology Group (RTOG). Após a avaliação e análise dos dados, verificou-se que os efeitos agudos obtidos com a técnica de RapidArcTM surgiram mais precocemente, quando comparados com técnica de IMRT. Por outro lado, com a técnica de IMRT registaram-se efeitos mais exacerbados, de alto Grau.

Effects of Low-Level Laser Therapy on Collagen Expression and Neutrophil Infiltrate in 5-Fluorouracil-Induced Oral Mucositis in Hamsters

Background and Objectives: Several studies have suggested that low-level laser therapy (LLLT) can ameliorate oral mucositis, however, the mechanisms involved are not well understood. The aim of this study was to investigate the mechanisms of action of LLLT on chemotherapy-induced oral mucositis, as related to effects on collagen expression and inflammation Materials and Methods: A hamster cheek pouch model of oral mucositis was used with all animals receiving intraperitoneal 5-fluorouracil, followed by surface irritation. Animals were randomly allocated into three groups, and treated with an InGaAIP diode laser at a wavelength of 660 nm and output power of 35 or 100 mW laser, or no laser Clinical severity of mucositis was assessed at four time-points by a blinded examiner Buccal pouch tissue was harvested from a subgroup of animals in each group at four time-points. Collagen was qualitatively and quantitatively evaluated after picrosinus staining. The density of the neutrophil infiltrate was also scored Results: Peak clinical severity of mucositis was reduced in the 35 mW laser group as compared to the 100 mW and control groups The reduced peak clinical severity of mucositis in the 35 mW laser group was accompanied by a decrease in the number of neutrophils and an increase in the proportion of mature collagen as compared to the other two groups. The total quantity of collagen was significantly higher in the control (no laser) group at the day 11 time-point, as compared to the 35 mW laser group, consistent with a more prolonged inflammatory response in the control group. Conclusion: This study supports two mechanisms of action for LLLT in reducing mucositis severity. The increase in collagen organization in response to the 35 mW laser indicates that LLLT promotes wound healing In addition, LLLT also appears to have an anti-inflammatory effect, as evidenced by the reduction in neutrophil infiltrate Lasers Surg Med 42 546-552, 2010. (C) 2010 Wiley-Liss, Inc.

Cyclooxygenase-2 and vascular endothelial growth factor expression in 5-fluorouracil-induced oral mucositis in hamsters: evaluation of two low-intensity laser protocols

The aim of this study was to investigate the mechanisms whereby low-intensity laser therapy may affect the severity of oral mucositis. A hamster cheek pouch model of oral mucositis was used with all animals receiving intraperitoneal 5-fluorouracil followed by surface irritation. Animals were randomly allocated into three groups and treated with a 35 mW laser, 100 mW laser, or no laser. Clinical severity of mucositis was assessed at four time-points by a blinded examiner. Buccal pouch tissue was harvested from a subgroup of animals in each group at four time-points. This tissue was used for immunohistochemistry for cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), and factor VIII (marker of microvessel density) and the resulting staining was quantified. Peak severity of mucositis was reduced in the 35 mW laser group as compared to the 100 mW laser and control groups. This reduced peak clinical severity of mucositis in the 35 mW laser group was accompanied by a significantly lower level of COX-2 staining. The 100 mW laser did not have an effect on the severity of clinical mucositis, but was associated with a decrease in VEGF levels at the later time-points, as compared to the other groups. There was no clear relationship of VEGF levels or microvessel density to clinical mucositis severity. The tissue response to laser therapy appears to vary by dose. Low-intensity laser therapy appears to reduce the severity of mucositis, at least in part, by reducing COX-2 levels and associated inhibition of the inflammatory response.

Gene expression profiling reveals molecular marker candidates of laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma is very common in head and neck cancer, with high mortality rates and poor prognosis. In this study, we compared expression profiles of clinical samples from 13 larynx tumors and 10 non-neoplastic larynx tissues using a custom-built cDNA microarray containing 331 probes for 284 genes previously identified by informatics analysis of EST databases as markers of head and neck tumors. Thirty-five genes showed statistically significant differences (SNR >= 11.01, p <= 0.001) in the expression between tumor and non-tumor larynx tissue samples. Functional annotation indicated that these genes are involved in cellular processes relevant to the cancer phenotype, such as apoptosis, cell cycle, DNA repair, proteolysis, protease inhibition, signal transduction and transcriptional regulation. Six of the identified transcripts map to intronic regions of protein-coding genes and may comprise non-annotated exons or as yet uncharacterized long ncRNAs with a regulatory role in the gene expression program of larynx tissue. The differential expression of 10 of these genes (ADCY6, AES, AL2SCR3, CRR9, CSTB, DUSP1, MAP3K5, PLAT, UBL1 and ZNF706) was independently confirmed by quantitative real-time RT-PCR. Among these, the CSTB gene product has cysteine protease inhibitor activity that has been associated with an antimetastatic function. Interestingly, CSTB showed a low expression in the tumor samples analyzed (p<0.0001). The set of genes identified here contribute to a better understanding of the molecular basis of larynx cancer, and provide candidate markers for improving diagnosis, prognosis and treatment of this carcinoma.

Quick chip assay using locked nucleic acid modified epithelial cell adhesion molecule and nucleolin aptamers for the capture of circulating tumor cells

The role of circulating tumor cells (CTCs) in disease diagnosis, prognosis, monitoring of the therapeutic efficacy, and clinical decision making is immense and has attracted tremendous focus in the last decade. We designed and fabricated simple, flat channel microfluidic devices polydimethylsiloxane (PDMS based) functionalized with locked nucleic acid (LNA) modified aptamers (targeting epithelial cell adhesion molecule (EpCAM) and nucleolin expression) for quick and efficient capture of CTCs and cancer cells. With optimized flow rates (10 μl/min), it was revealed that the aptamer modified devices offered reusability for up to six times while retaining optimal capture efficiency (>90%) and specificity. High capture sensitivity (92%) and specificity (100%) was observed in whole blood samples spiked with Caco-2 cells (10-100 cells/ml). Analysis of blood samples obtained from 25 head and neck cancer patients on the EpCAM LNA aptamer functionalized chip revealed that an average count of 5 ± 3 CTCs/ml of blood were captured from 22/25 samples (88%). EpCAM intracellular domain (EpICD) immunohistochemistry on 9 oral squamous cell carcinomas showed the EpICD positivity in the tumor cells, confirming the EpCAM expression in CTCs from head and neck cancers. These microfluidic devices also maintained viability for in vitro culture and characterization. Use of LNA modified aptamers provided added benefits in terms of cost effectiveness due to increased reusability and sustainability of the devices. Our results present a robust, quick, and efficient CTC capture platform with the use of simple PDMS based devices that are easy to fabricate at low cost and have an immense potential in cancer diagnosis, prognosis, and therapeutic planning.

BUBR1 expression in benign oral lesions and squamous cell carcinomas: Correlation with human papillomavirus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Gene expression profiling reveals molecular marker candidates of laryngeal squamous cell carcinoma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Apoptosis in tongue squamous cell carcinoma and its correlation with clinically occult cervical metastasis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Carcinogênese de cabeça e pescoço: impacto do polimorfismo MTHFD1 G1958A

OBJETIVO: Investigar o polimorfismo MTHFD1 G1958A envolvido no metabolismo do folato no risco para o câncer de cabeça e pescoço e verificar a associação entre esse polimorfismo com fatores de risco e características clínico-histopatológicas. MÉTODOS: Estudo retrospectivo que avaliou o polimorfismo MTHFD1 G1958A em 694 indivíduos (240 pacientes e 454 controles), por meio da técnica de análise de polimorfismo de comprimento de fragmento de restrição. Para análise estatística foram utilizados os testes de regressão logística múltipla e qui-quadrado. RESULTADOS: Tabagismo e idade superior a 42 anos foram preditores da doença (p < 0,05). Os genótipos MTHFD1 1958GA ou AA foram associados ao tabagismo (p = 0,04) e etilismo (p = 0,03) e estão presentes em maior proporção em tumores com estádios mais avançados (p = 0,04) e em pacientes com menor sobrevida (p = 0,03). CONCLUSÃO: A presença do polimorfismo MTHFD1 G1958A associada aos hábitos tabagista e etilista aumenta o risco para desenvolvimento de câncer de cabeça e pescoço.

Study of the effects of exposure to ionizing irradiation on the materials used for dental restoration

A quantitative study was made about the effects caused by ionizing irradiation on materials used for dental restoration (amalgams, compound resins and compomere), aiming to alleviate in bearers of head and neck cancer, the possible harmful effects of radiotherapy perceived when the repaired teething is within the radiation field. Research also encourages further studies for new alternative materials to be used in dental repair of patients submitted to radiotherapy for head and neck cancer. Test samples were submitted to a gamma radiation beam coming from a cobalt-therapy source and analyzed according to the X-ray fluorescence technique, comparing the chemical composition of the samples before and after irradiation. Radiation detectors such as an ionization chamber and a Geiger-Muller were used to measure the rate of residual dose. Gamma spectrometry with Nal detectors was also performed on the same samples. Results showed that there was no significant change in the chemical composition and that at post-irradiation, samples did not exhibit radiation emission, that is to say they had not become radioactive.

Avaliação da qualidade de vida relacionada ao impacto da terapia com iodo-131 em pacientes com câncer bem diferenciado de tireóide (CDT) na infância

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB