design: Total RNA was extracted using the standard TRIzol method from matched tumours and normal samples. RNA was quantitated using QUBIT, and the quality was checked using TapeStation. mRNA libraries were prepared using Illumina TruSeq RNA Library Prep Kit v2 (Biolabs and New England Biolabs, no date). In brief, mRNA was isolated using oligo-dT beads, followed by fragmentation. Fragmented RNA was then converted to cDNA, and adaptor ligation was performed. Size selection was performed on adaptor-ligated libraries using AMPure beads. The libraries were amplified and checked on a tape station to determine the library size.