gentetics molecular biology

BACKGROUND: The standard therapy regimen of conventional osteosarcoma includes neoadjuvant chemotherapy followed by surgical resection and postoperative chemotherapy. The percentage of necrotic tissue following induction chemotherapy is assessed by using the Huvos grading system, which classifies patients as "poor responders" (PR) and "good responders" (GR). The aim of this study was to identify molecular markers expressed differentially between good and poor responders to neoadjuvant chemotherapy in order to predict the response to chemotherapy in conventional osteosarcomas before beginning treatment...

Primary malignant bone tumours, osteosarcomas, and Ewing sarcomas are rare diseases which occur mainly in adolescents and young adults. With the current therapies, some patients remain very difficult to treat, such as tumour with poor histological response to preoperative CT (or large initial tumour volume for Ewing sarcomas not operated), patients with multiple metastases at or those who relapsed. In order to develop new therapies against these rare tumours, we need to unveil the key driving factors and molecular abnormalities behind the malignant characteristics and to broaden our understanding of the phenomena sustaining the metastatic phenotype and treatment resistance in these tumours...

The diagnosis of Ewing's malignant tumor in the young still raises major problems, either from a clinical point of view because of its rarity, its pluri-potentiality and various symptoms, or on imaging because of its numerous pitfalls. Accordingly the disease is often misdiagnosed as osteomyelitis. Only a high quality biopsy can determine histological diagnosis of undifferentiated small round cell tumor. The chromosomic study shows a specific (11;22)(q24;q12) translocation, and immunocytochemistry and molecular biology show the tumor's neuroectodermal origin...