GFAP and central nervous system cancer: Given the major potential of GFAP as a biomarker of reactive astrogliosis for neurodegenerative and neurological diseases, as well as glioma, and its implementation in clinical settings (Abdelhak et al., 2022; Glass et al., 2010; Heimfarth et al., 2022; Jiwaji & Hardingham, 2022; Messing & Brenner, 2020; Mondello et al., 2021; van Asperen, Fedorushkova, et al., 2022), it is paramount to understand how the physio‐chemical characteristics of GFAP may influence its detection which may underlie the differential diagnostic performance of GFAP in different matrices.