GFAP and neoplasm: The association of GFAP with OS is consistent with the loss of GFAP in high-grade tumors [18, 19] and increased tumor growth [20]; however, more recently, the relevance of different isoforms of GFAP [27] and an upregulation of GFAP in non-neoplastic astrocytes as a reaction to tumor growth have also been described by different groups [28, 29].