DNA was extracted using spin columns (QIAamp DNA Micro Kit, Qiagen, NL) according to the manufacturer’s protocol with ~15 mg of tumor tissue. Quantification of eluted DNA was performed on a Qubit 4.0 fluorometer using a dsDNA BR Assay (Thermo Fisher, USA) and assessed for purity using the NanoDrop 260/280 ratio (NanoDrop, Thermo Fisher).
For intraoperative NDMA analysis, the tumor biopsy was immediately placed in lysis buffer (Qiagen) at the operating room, allowing digestion to begin during transport to the laboratory.10 (link) Upon arrival, the biopsy lysate was homogenized for 30 s (TissueLyser, Qiagen) and digested for 10 min at 56°C and 5 min at 70°C. This reduced the total sample handling and DNA extraction time to 30 min. The DNA quantity and quality were still above the required standards.
For intraoperative NDMA analysis, the tumor biopsy was immediately placed in lysis buffer (Qiagen) at the operating room, allowing digestion to begin during transport to the laboratory.10 (link) Upon arrival, the biopsy lysate was homogenized for 30 s (TissueLyser, Qiagen) and digested for 10 min at 56°C and 5 min at 70°C. This reduced the total sample handling and DNA extraction time to 30 min. The DNA quantity and quality were still above the required standards.
