Detection of CF-DNA in Patients With Gastrointestinal Stromal Tumors (GIST)

Activating mutations of the kinases CKIT or PDGFRA can be detected in 90% of cases by DNA sequence analysis of a pathological specimen. These mutated genomic DNA fragments are highly specific for the tumor and are released by the tumor into the circulation. Allele-specific PCR can be used to specifically amplify and quantify mutated CKIT and PDGFR DNA fragments. The current trial aims to evaluate whether tumor DNA carrying mutations for CKIT and PDGFRA can be detected and quantified in the plasma of patients with active GIST, and whether detection can be correlated with the clinical course of disease either under therapy or in progressive disease irrespective of current therapy.