GENE-18. USE OF PRIMARY TEETH AND A TOOTH BRUSH AS SOURCES OF DNA IN AN ANAPLASTIC ASTROCYTOMA CASE

BACKGROUND Anaplastic astrocytomas (AA) are aggressive glial cancers with poor prognosis and high recurrence. Although a majority of astrocytomas are sporadic, recent studies have shown that up to 10% of patients with cancer may have an underlying cancer predisposition syndrome. Identification of germline mutations allows for proper management and screening for cancer in patients and their at-risk family members. In this study, we present a unique case of two siblings who developed AA within 8 years of each other. Clinical whole exome testing of our patient’s germline DNA revealed a maternally inherited PTCH2 mutation of unknown significance. The PTCH2 gene is highly homologous to the PTCH1 gene, which is associated with increased risk for basal cell carcinoma, medulloblastoma, rhabdomyoma and ovarian fibroma. However, this has never been described in a glioma before.