[Recent progress of molecular diagnosis in pediatric malignancies]

Recent progress of molecular and cytogenetic techniques has led to remarkable advances in molecular diagnosis of pediatric malignancies, including malignant bone and soft tissue sarcoma (MSTS). Fusion genes, such as EWS-FLI1 and PAX3-FKHR, were cloned at the chromosome breakpoints of t(11;22) and t(2;13) in Ewing's sarcoma and rhabdomyosarcoma, respectively. Minimal residual disease can be detected by reverse transcriptase-polymerase chain reaction using these translocations. These fusion genes contribute to differential diagnosis of pediatric small round cell tumor, which was difficult to diagnose morphologically. Some of these fusion genes, including SYT-SSX in synovial sarcoma and EWS-FLI1 in Ewing sarcoma, have been reported to be associated with prognosis. Recently, genome-wide searches using microarray and single nucleotide polymorphisms have been performed in pediatric malignancies. These advances have led to the increased importance of molecular diagnosis as well as morphological diagnosis. We review here the recent progress of molecular diagnosis in pediatric malignancies.