TP53 and granular cell tumor: Furthermore, two well-established GCT cell lines, originating from different anatomical locations and harboring a different TP53 background (TP53 mutant/loss in NCCIT from the mediastinum and TP53 wild-type in 2102Ep from the testis), were modified using a CRISPR/Cas9-mediated TP53 knock-out model system.