TTR and neoplasm: We must note that in the absence of tumour purification (e.g., via 5ALA-based fluorescence-activated cell sorting) from tissue biopsies derived from the GBM invasive margin, as previously demonstrated by us for transcriptomic studies15,16, we cannot exclude that α-trypsin, actin, apolipoprotein A1 and transthyretin expression represents non-disease astrocytic or myeloid cell populations.