Thais Bianca Brandão

Osteonecrosis of the mandible associated with bevacizumab therapy

Bevacizumab is a humanized antibody that blocks vascular endothelial growth factor and is of great value for the treatment of advanced cancer. Several adverse effects following its administration have been reported. To date, only 8 cases of osteonecrosis of the jaws associated with bevacizumab (without any association with bisphosphonates) have been reported. The aim of this article was to describe an original case of bevacizumab-related osteonecrosis of the jaw. A 61-year-old man diagnosed with advanced renal cell carcinoma was undergoing treatment with intravenous bevacizumab and temsirolimus when he spontaneously developed mandible osteonecrosis, which resolved after 3 months of conservative management. The present case reinforces recent speculation that the anti-angiogenic properties of bevacizumab may represent a potential new source of osteonecrosis of the jaws in patients undergoing cancer treatment. Multidisciplinary teams in cancer care should be aware of the possible association between osteonecrosis of the jaw and bevacizumab therapy.

Insights into immune responses in oral cancer through proteomic analysis of saliva and salivary extracellular vesicles.

The development and progression of oral cavity squamous cell carcinoma (OSCC) involves complex cellular mechanisms that contribute to the low five-year survival rate of approximately 20% among diagnosed patients. However, the biological processes essential to tumor progression are not completely understood. Therefore, detecting alterations in the salivary proteome may assist in elucidating the cellular mechanisms modulated in OSCC and improve the clinical prognosis of the disease. The proteome of whole saliva and salivary extracellular vesicles (EVs) from patients with OSCC and healthy individuals were analyzed by LC-MS/MS and label-free protein quantification. Proteome data analysis was performed using statistical, machine learning and feature selection methods with additional functional annotation. Biological processes related to immune responses, peptidase inhibitor activity, iron coordination and protease binding were overrepresented in the group of differentially expressed proteins. Proteins related to the inflammatory system, transport of metals and cellular growth and proliferation were identified in the proteome of salivary EVs. The proteomics data were robust and could classify OSCC with 90% accuracy. The saliva proteome analysis revealed that immune processes are related to the presence of OSCC and indicate that proteomics data can contribute to determining OSCC prognosis.

A targeted proteomic strategy for the measurement of oral cancer candidate biomarkers in human saliva

Head and neck cancers, including oral squamous cell carcinoma (OSCC), are the sixth most common malignancy in the world and are characterized by poor prognosis and a low survival rate. Saliva is oral fluid with intimate contact with OSCC. Besides non‐invasive, simple, and rapid to collect, saliva is a potential source of biomarkers. In this study, we build an SRM assay that targets fourteen OSCC candidate biomarker proteins, which were evaluated in a set of clinically‐derived saliva samples. Using Skyline software package, we demonstrated a statistically significant higher abundance of the C1R, LCN2, SLPI, FAM49B, TAGLN2, CFB, C3, C4B, LRG1, SERPINA1 candidate biomarkers in the saliva of OSCC patients. Furthermore, our study also demonstrated that CFB, C3, C4B, SERPINA1 and LRG1 are associated with the risk of developing OSCC. Overall, this study successfully used targeted proteomics to measure in saliva a panel of biomarker candidates for OSCC.

Micromorphology of the Dental Pulp Is Highly Preserved in Cancer Patients Who Underwent Head and Neck Radiotherapy

INTRODUCTION Teeth are often included in the radiation field during head and neck radiotherapy, and recent clinical evidence suggests that dental pulp is negatively affected by the direct effects of radiation, leading to impaired sensitivity of the dental pulp. Therefore, this study aimed to investigate the direct effects of radiation on the microvasculature, innervation, and extracellular matrix of the dental pulp of patients who have undergone head and neck radiotherapy. METHODS Twenty-three samples of dental pulp from patients who finished head and neck radiotherapy were analyzed. Samples were histologically processed and stained with hematoxylin-eosin for morphologic evaluation of the microvasculature, innervation, and extracellular matrix. Subsequently, immunohistochemical analysis of proteins related to vascularization (CD34 and smooth muscle actin), innervation (S-100, NCAM/CD56, and neurofilament), and extracellular matrix (vimentin) of the dental pulp was performed. RESULTS The morphologic study identified preservation of the microvasculature, nerve bundles, and components of the extracellular matrix in all studied samples. The immunohistochemical analysis confirmed the morphologic findings and showed a normal pattern of expression for the studied proteins in all samples. CONCLUSIONS Direct effects of radiotherapy are not able to generate morphologic changes in the microvasculature, innervation, and extracellular matrix components of the dental pulp in head and neck cancer patients.

Increased risk for radiation-related caries in cancer patients using topical honey for the prevention of oral mucositis

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Structural Analysis of Enamel in Teeth from Head-and-Neck Cancer Patients Who Underwent Radiotherapy

Objective: To analyze macroscopic, microscopic, and ultrastructural aspects of enamel from head-and-neck cancer patients submitted to radiotherapy. Materials and Methods: Twenty sound extracted permanent molars were used and divided into 2 groups. The experimental group consisted of 10 molars from head-and-neck cancer patients submitted to radiotherapy with total doses that ranged from 50 to 70 Gy. Ten molars from patients who did not receive radiotherapy were matched with experimental-group samples by anatomic tooth group and comprised the control group. To perform a macroscopic analysis, standardized photos of different enamel faces were taken with a camera. Teeth were subjected to longitudinal cuts and hand polished to a final thickness of 0.1 mm. Enamel was analyzed under polarized light microscopy, and optical retardation values of birefringence were calculated in cervical, cusp, and occlusal pit areas. Subsequently, the same enamel areas were analyzed by scanning electron microscopy. Data from optical retardation values were statistically analyzed by 2-way ANOVA and Fishers test (α < 0.05). Results: No macroscopic differences were observed between the irradiated and control groups. Polarized light microscopy analysis revealed that cervical enamel exhibited darker areas characterized by discrete birefringence patterns compared to the control enamel. Optical retardation values were only significantly different in the cervical enamel of the irradiated and control groups (p < 0.0001). Scanning electron microscopy analysis revealed more evident interprismatic spaces in the cervical and outer cusp enamel of irradiated samples. Conclusions: Head-and-neck radiotherapy reduced optical retardation values of birefringence in cervical enamel, and the interprismatic spaces became more evident.

Tissue microarray use for immunohistochemical study of ameloblastoma

BACKGROUND Ameloblastoma is a locally aggressive odontogenic tumor with high rates of recurrence. To better understand the molecular basis of ameloblastoma, tissue microarray (TMA) may represent a useful tool. However, despite TMA has been considered a high-throughput technique for different human neoplasms, it remains to be validated in the ameloblastoma context. Therefore, the objective of this study was to validate TMA for immunohistochemical study of ameloblastoma, determining its most appropriate design. METHODS Forty cases of ameloblastoma were manually distributed in two TMA blocks assembled in triplicate containing 1.0- and 2.0-mm cores (20 cases each). Immunohistochemistry for cytokeratins 14 and 19, and Bcl-2 and Ki-67 was performed, and semiquantitative analysis was performed. Results obtained with TMA sections were compared to their corresponding conventional whole-section slides (CWSS). RESULTS Kappa statistical test demonstrated that both 1.0- and 2.0-mm cores assessed as duplicate or triplicate significantly correlated with CWSS, with higher levels obtained using Ki67 (k = 0.98, 0.97, 0.88, 0.87) and CK19 (k = 0.62, 0.58, 0.85, 0.85). There was no significant difference between 1.0- and 2.0-mm cores, and between duplicate and triplicate values. 1.0-mm TMA showed a higher index of core loss (33.74% vs. 4.99%). CONCLUSION Using a manual arrayer, it was demonstrated that 1.0-mm TMA arranged in duplicate is a valid method for ameloblastoma immunohistochemical study with satisfactory levels of agreement between TMA cylinders and CWSS.

Obturator prostheses versus free tissue transfers: A systematic review of the optimal approach to improving the quality of life for patients with maxillary defects.

STATEMENT OF PROBLEM Patient perspectives on the treatment options for maxillary defects, which include free tissue transfers or obturator prostheses, may help eliminate current uncertainty as to the best choice of treatment plan. PURPOSE The purpose of this systematic review was to evaluate the quality of life (QoL) of patients with maxillary defects who had undergone restoration with obturator prostheses and/or free tissue transfers. MATERIAL AND METHODS A systematic search of Medline/PubMed and Web of Science databases for articles published before April 2015 was performed by 2 independent reviewers. A manual search of articles published from January 2005 to March 2015 was also conducted. Studies published in English that evaluated the QoL in patients with head and neck cancers were included. The Cohen kappa method was used to calculate inter-reviewer agreement. RESULTS Ten studies were included. The University of Washington Head and Neck Questionnaire (UW-QOL) was most commonly used to measure QoL. The majority of maxillary defects were Class IIa-b. Two studies reported that the global QoL for patients with obturator prostheses is equivalent to or even better than that of other chronic disease populations. One study revealed no significant difference in QoL when the 2 treatment options were compared. CONCLUSIONS The limited data indicate that the QoL of patients treated with obturator prostheses and that of patients free of tumors is similar. Well-designed clinical studies are necessary to draw definitive conclusions about how obturator prostheses compare with free tissue transfers in terms of affecting patient QoL.

Postradiation Matrix Metalloproteinase-20 Expression and Its Impact on Dental Micromorphology and Radiation-Related Caries

Recent evidence suggests that head-and-neck radiotherapy (HNRT) increases active forms of matrix metalloproteinase-20 (MMP-20) in human tooth crowns, degrading the dentin-enamel junction (DEJ) and leading to enamel delamination, which is a pivotal step in the formation of radiation-related caries (RRC). Additional participation of enzymatic degradation of organic matrix components in caries progression was attributed to MMP-20 in dentin. Therefore, the current study tested the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes to the enamel and dentin. Thirty-six teeth were studied, including 19 post-HNRT specimens and 17 nonirradiated controls. Optical light microscopy was used to investigate the micromorphological components of the DEJ, dentin-pulp complex components, and carious dentin. The samples were divided into 2 subgroups: nondemineralized ground sections (n = 20) and demineralized histological sections (n = 16). In addition, immunohistochemical analysis using the immunoperoxidase technique was conducted to semiquantitatively assess MMP-20 expression in the DEJ, dentin-pulp complex components, and carious dentin. No apparent damage to the DEJ microstructure or other dentin-pulp complex components was observed and no statistically significant differences were detected in MMP-20 expression (p > 0.05) between the irradiated and control groups. This study rejected the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes. Hence, direct effects of radiation may not be regarded as an independent factor to explain aggressive clinical patterns of RRC.

Integrative analysis to select cancer candidate biomarkers to targeted validation

Targeted proteomics has flourished as the method of choice for prospecting for and validating potential candidate biomarkers in many diseases. However, challenges still remain due to the lack of standardized routines that can prioritize a limited number of proteins to be further validated in human samples. To help researchers identify candidate biomarkers that best characterize their samples under study, a well-designed integrative analysis pipeline, comprising MS-based discovery, feature selection methods, clustering techniques, bioinformatic analyses and targeted approaches was performed using discovery-based proteomic data from the secretomes of three classes of human cell lines (carcinoma, melanoma and non-cancerous). Three feature selection algorithms, namely, Beta-binomial, Nearest Shrunken Centroids (NSC), and Support Vector Machine-Recursive Features Elimination (SVM-RFE), indicated a panel of 137 candidate biomarkers for carcinoma and 271 for melanoma, which were differentially abundant between the tumor classes. We further tested the strength of the pipeline in selecting candidate biomarkers by immunoblotting, human tissue microarrays, label-free targeted MS and functional experiments. In conclusion, the proposed integrative analysis was able to pre-qualify and prioritize candidate biomarkers from discovery-based proteomics to targeted MS.