Identifying Molecular Markers for the Sensitive Detection of Residual AT/RT Cells

Background: AT/RT has specific molecular features, which may serve as molecular markers for residual tumor cell detection in liquid biopsies. We evaluated a proof-of-principle method to detect residual AT/RT cells.

Patients and methods: A total of 7/150 patients were selected, each molecular genetically diagnosed with AT/RT. Germline mutations were excluded. Tumor samples were FFPE. DNA was extracted from the patients' PBL and CSF. MLPA, PCR and sequencing were used to identify the tumor's mutations. Residual tumor cell search used mutation specific primers and real-time PCR.

Results: The detection limit for residual tumor cell search ranged from 1% – 18% depending on the quality of the template provided. Residual tumor cell search in PBL and CSF was negative for all seven patients.

Discussion: The SMARCB1 region of chromosome 22 is liable to dsDNA breaks. The negative results for residual tumor cell search in the patient's PBL and CSF are due to the method's lack of sensitivity or the patient's PBL/CSF was negative of tumor cells respectively.

Supported by the „Fördergemeinschaft Kinderkrebszentrum Hamburg e.V.“