Qiaamp dna blood maxi kit

Methods for DNA extraction and genotyping have been previously described (Brown et al., 2014 (link); Porter et al., 2018a (link), b ). Briefly, QIAamp DNA Blood Maxi Kits (Qiagen, Hilden, Germany) were used for DNA extraction from whole blood as per manufacturer’s instructions. TaqMan^® genotyping assays (Life Technologies, Carlsbad, CA) for APOE (rs7412, assay ID: C____904973_10; rs429358, assay ID: C___3084793_20) and COMT (rs4680, assay ID: C__25746809_50) were performed on a QuantStudio 12K Flex™ Real-Time-PCR systems (Applied Biosystems, Foster City, CA) using TaqMan^® GTXpress™ Master Mix (Life Technologies) following manufacturer’s instructions. APOE status was defined by the presence (1 or 2 copies; APOE ε4+ve) or absence (0 copies; APOE ε4-ve) of the APOE ε4 allele. Further, all analyses were performed based on a dominant model for the COMT Val allele (COMT^Val = COMT^Val/Val/COMT^Val/Met; COMT^Met = COMT^Met/Met).

The meningioma specimens were obtained within 30 min after the tumour removal, dissected into three portions, and processed for DNA/RNA extraction [20 ], tissue freezing at -80 °C [23 (link)], and cell culture initiation [22 (link)], according to previously published studies. Genomic DNA from the tumour and cell lines was extracted from an average of 30 mg of frozen tissue or 5×10⁶ cells per cell line using All PrepDNA/RNA kits (Qiagen, Hilden, Germany) according to the manufacturer's instructions. DNA from the blood samples was extracted from 3 mL of whole blood using QIAamp DNA Blood Maxi kits (Qiagen), as per the manufacturer's instructions. For the cell lines, cells were collected within an average of 5.1 days (±1.2 days) after the tumour retrieval. All cells were harvested in passage zero before flask expansion and before completing the time taken to double the cells' number.