Detection of RAF fusion transcripts in FFPE samples of Medullablastoma and Ependymom in Iraqi children with RT-RQPCR assays

الملخص

Medulloblastomas and ependymomas are the most common malignant brain tumors in children. However genetic abnormalities associated with their development and prognosis remain unclear. Recently two gene fusions, KIAA1549–BRAF and SRGAP3–RAF1 have been detected in a number of brain tumours. We report here our development and validation of RT-RQPCR assays to detect various isoforms of these two fusion genes in formalin fixed paraffin embedded (FFPE) tissues of medulloblastoma and ependymoma. We examined these fusion genes in 44 paediatric brain tumours, 33 medulloblastomas and 11 ependymomas. We detected both fusion transcripts in 8/33, 5/33 SRGAP3 ex10/RAF1 ex10, and 3/33 KIAA1549 ex16/BRAF ex9, meduloblastomas but none in the 11 ependymomas examined. This investigation provided evidence to the value of RT-RQPCR assays for the detection of these fusion genes in large-scale studies on FFPE tissues. The study also reports the first detection of RAF fusion genes in meduloblstomas.