Bi-directional Sanger sequencing of ATRX is performed using PCR primers designed to target hotspot mutations in exons 8-10, 12-15, 17, 18, 21, 22, 26, 30-32, and 35.
This assay detects mutations in the gene ATRX, which encodes for a protein involved in chromatin remodeling and telomere biology. Mutations in ATRX have been reported in all types of cancers such as brain tumors. ATRX is mutated in 71% of grade II and III astrocytomas, 68% of oligoastrocytomas, and 57% of secondary glioblastoma. ATRX mutations in brain tumors are frequently detected with IDH1 and IDH2 mutations. The presence of these two mutations defines a specific subgroup of brain tumors that is important diagnostically. Patients with this molecularly characterized subtype have significantly longer survival. Mutations in ATRX have also been reported in 13% of MDS patients, 19% of pancreatic neuroendocrine tumors, 10% of endometrial tumors, 8% of colon cancers and 7% of lung cancers.
- Peripheral blood: 5 mL in EDTA tube.
- Bone marrow: 2 mL in EDTA tube.
- FFPE solid tumor tissue: Paraffin block is preferred. Alternatively, send 1 H&E slide plus 5-10 unstained slides cut at 5 or more microns. Please use positively-charged slides and 10% NBF fixative. Do not use zinc fixatives.
- Fresh tissue: 1 cm3 fresh tissue that is mostly tumor in RPMI.
Use cold pack for transporting block during summer to prevent block from melting. Slides can be packed at room temperature.