Involvement of MET/TWIST/APC combination or the potential role of ossification factors in pediatric high-grade osteosarcoma oncogenesis.

Dysregulated cell growth or differentiation due to misexpression of developmental critical factors seems to be a decisive event in oncogenesis. As osteosarcomas are histologically defined by malignant osteoblasts producing an osteoid component, we prospected in pediatric osteosarcomas treated with OS94 protocol the genomic status of several genes implied in ossification processes. In 91 osteosarcoma cases, we focused on the analysis of the fibroblast growth factor receptors (FGFRs) TWIST, APC, and MET by allelotyping, real-time quantitative polymerase chain reaction, gene sequencing, and protein polymorphism study.

KIT gene in pediatric osteosarcomas: could it be a new therapeutic target?

In our previous study, a frequent rearrangement at 4q12 has been identified by allelotyping in our large and homogeneous population of pediatric osteosarcomas and it was significantly linked to c-kit protein overexpression. To confirm and understand the involvement of KIT in this tumor, the next step of the study was designed to detect the potential mutations of KIT gene by sequencing the frequently mutated exons 6, 8, 10, 11, 13, 17 and 21 and, in case of unmutated samples, to confirm the genomic amplifications of the wild-type receptor by real-time quantitative PCR (QPCR). A new microsatellite and QPCR targeting PDGFRA was also added to check the accuracy of the 4q11-12 locus.

Lymphocyte data in Epstein-Barr-virus induced post-transplant lymphoproliferative disorder treated by rituximab.

Viral infection is an important cause of morbidity and mortality in the post-allograft period. Recently, a new therapeutic approach was developed in post-transplant lymphoproliferative disorder (PTLD) induced by Epstein-Barr virus (EBV): the anti-CD20 monoclonal antibody or rituximab. We performed a single-center study on the treatment effectiveness of rituximab in three EBV-induced PTLD and evaluated biologic data, such as T and B lymphocytes count, during PTLD development and treatment.