GFAP and neoplasm: In our study, leveraging on the combination of the Parsortix and DEPArray instrumentations, we set up a new approach based on isolating CTCs from blood depending on cell size and then using GFAP (glial fibrillary acidic protein) as the main tumor astrocyte cell marker [26], with EGFR (epidermal growth factor receptor) and ki67 (proliferation marker protein), as described by Krol et al. [17].