Expression of BARD1 β Isoform in Selected Pediatric Tumors.

Currently, many new possible biomarkers and mechanisms are being searched and tested to analyse pathobiology of pediatric tumours for the development of new treatments. One such candidate molecular factor is (BRCA1 Associated RING Domain 1)-a tumour-suppressing gene involved in cell cycle control and genome stability, engaged in several types of adult-type tumours. The data on significance in childhood cancer is limited. This study determines the expression level of and its isoform beta (β) in three different histogenetic groups of pediatric cancer-neuroblastic tumours, and for the first time in chosen germ cell tumours (GCT), and rhabdomyosarcoma (RMS), using the qPCR method. We found higher expression of beta isoform in tumour compared to healthy tissue with no such changes concerning full-length. Additionally, differences in expression of β between histological types of neuroblastic tumours were observed, with higher levels in ganglioneuroblastoma and ganglioneuroma. Furthermore, a higher expression of β characterized yolk sac tumours (GCT type) and RMS when comparing with non-neoplastic tissue. These tumours also showed a high expression of the (Telomerase Reverse Transcriptase) gene. In two RMS cases we found deep decrease of BARD1 β in post-chemotherapy samples. This work supports the oncogenicity of the beta isoform in pediatric tumours, as well as demonstrates the differences in its expression depending on the histological type of neoplasm, and the level of maturation in neuroblastic tumours.