R. Fraser1, C.C. Young1, M. Nicola1, J. Suttle1, R. Kenyon 2, N. Manton3, S. Moore1
1 SA Cancer Cytogenetics Unit, Genetics and Molecular Pathology Directorate, SA Pathology, Adelaide, South Australia
2 ACRF Cancer Genome Facility, Adelaide, South Australia
3 Anatomical Pathology Directorate, Women’s and Children’s Hospital, Adelaide, South Australia
Medulloblastoma is a highly malignant embryonal tumour of the cerebellum, and is the most common form of malignant paediatric brain tumour. Treatment involves surgical resection, and in some cases radiation therapy and chemotherapy. Current recurrence free survival is approximately 50-70%. Traditional clinical prognostication and stratification incorporates clinical factors (age, presence of metastases, extent of resection), histological/immunohistochemical subgrouping, and tumour cytogenetics. More recently, molecular profiling of medulloblastoma cases has suggested the existence of distinct subgroups that differ in their demographics, transcriptomes, somatic genetic events, and clinical outcomes. Consensus was reached recently for four main molecular subgroups of medulloblastomoa (ie Wnt, Shh, Group 3, and Group 4) and there is evidence to suggest that some arise from different cellular origins. The demanding nature of tumour culturing and karyotyping has led us to investigate the use of SNP-array analysis to provide critical somatic genetic information to help stratify patients into one of these subgroups. We now report the results of a small pilot study of local medulloblastoma patients for whom we have performed SNP-array and karyotyping and compared our data with the Children’s Oncology Group findings. SNP-array results were easier to interpret than karyotyping, could be performed in a shorter time frame, since there is no need for culture of FISH analysis, and resulted in correct molecular classification of medulloblastoma.
Rachel works as a medical scientist in the cancer cytogenetics laboratory in Adelaide.