RNA-seq of pdx tumor tissue: gastric cancer
Total RNA was extracted from primary tumor tissue taken from patients or implanted tumor tissue from PDX mice using the Qiagen Allprep DNA/RNA Mini Kit. After RNA concentration and quality were assessed, the library was produced by following the manufacturer's instructions using the QIAseq Stranded mRNA Library Kit starting with 5 g total RNA. First, mRNA was enriched using the Oligo-dT probe capture. The enriched polyA+ mRNAs were fragmented and converted into cDNA with reverse transcriptase, and then converted into double-stranded DNAs, which underwent end-repair, A-tailing, and adapter ligation. The constructed libraries were amplified by 7 cycles of PCR, and quantified and assessed using Qubit and Tapestation 4150 . After normalization, the library was sequenced on NextSeq 550Dx machines in paired-end 2x150 bp.