POLR2L and glioma: Despite using a small number of samples, we were able to confirm that our samples can be analysed in a similar manner to regular TCRs; for example, we were able to retrieve gene expression changes in GBs compared to lower grade gliomas, such as POLR2L [27] and ZMYND11 [28], as potential candidates for glioma malignancy, and to classify the samples into molecular glioma subtypes with differential clinical outcomes (Fig 4) according to the predominance of associated transcriptional signatures [14, 15].