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Relationships among KRAS mutation status, expression of RAS pathway signaling molecules, and clinicopathological features and prognosis of patients with colorectal cancer

Study Design: Ameloblastoma is a benign odontogenic tumor of epithelial origin, with locally aggressive behavior; and due to its invasiveness has increased recurrence rates. It is more frequent in the mandible than the maxilla. Surgical treatment is performed with approaches ranging from conservative to radical surgery, either followed by microvascular reconstruction, or not. Adjuvant treatment has shown better local control in refractory cases. Multiple relapses are associated with BRAF gene mutation at codon 600. Objective: This case series aimed to describe the clinical, imaging, histopathological, therapeutic and mutational characterization of 3 patients with refractory ameloblastoma in the maxilla. Methods: Data of 3 patients were collected, and descriptions were provided of procedures such as clinical, imaging, surgical technique, histopathological subtype and molecular analysis for detection of BRAFV600E mutation. Results It was obtained a locoregional control after RT of two cases described. After BRAF mutation molecular analysis, no patient presented it. Conclusion: Surgery remains the gold standard for the treatment of ameloblastomas, even in refractory cases; however, an expanded approach to obtain free surgical margins, and reconstruction of the maxilla itself may be challenging. Adjuvant radiotherapy is still a controversial topic, but could favor reduction of the local recurrence rate in cases where the surgical margins are compromised after surgical resection. Further studies will be necessaries for analysis of the BRAFV600E mutation, for therapeutic purposes.

Hintergrund Die Weltgesundheitsorganisation (WHO) plant eine Aktualisierung der WHO-Klassifikation maligner Lymphome.

Mutations in the BRAF gene are well known for their oncogenic effects. Point mutations in V599 are particularly oncogenic and are considered important for therapeutic purposes. Along with wild type, other V599 mutated BRAF variants viz. V599E, V599D and V599R are reported and crystals of the former two with inhibitor (BAY43-9006) are further detailed. Both wild-type and mutated BRAF forms show similar interaction patterns with BAY43-9006, but the 599th residue did not show any involvement in the interactions. Upon BAY43-9006 binding, kinase domains of both forms were found adopting essentially identical conformations. However, BAY43-9006 shows a varied activity profile in the case of the wild and V599E variant of the BRAF protein. Furthermore, MMGBSA binding energy results for all four BRAF variants, further revealed the importance of the 599th residue. In-depth analysis viz. molecular dynamics, residue correlation studies and residue interaction network (RIN) analyses were conducted, providing a deep insight into the 599th residue and its impact on the overall dynamics of BRAF protein. Our findings reveal that the mutated residue at the 599th position not only changed the BAY43-9006–BRAF binding behaviour but also produced a massive impact on the overall dynamic behaviour of the protein. The insights obtained herein could be of great relevance for designing new BRAF inhibitors aimed at getting ideal activity against all BRAF forms.