This pilot study opens new perspectives in the understanding of the peptidomic profile of GBM through saliva, suggesting a panel of candidate peptide biomarkers, including peptide fragments of ANXA1, CFL1, GLUL, PFN1, H2AC12, ACTB, and HBB, which, having already been identified in other GBM samples and cell lines, warrant further exploration and validation on large scale with the aim of promoting progress in precision medicine, improving diagnostic and prognostic capabilities in the clinical setting. Here, PFN1 is linked to glioblastoma.