Glioblastoma (GBM) is the most common and lethal primary brain tumor. Identifying blood biomarkers that reflect the tumor's status is a major unmet need for optimal clinical management. 5-ALA (5-Aminolevulinic Acid) administration leads to the accumulation of fluorescent Protoporphyrin IX (PpIX) in GBM cells, allowing identification during surgery. This project aims to leverage 5-ALA induced fluorescence to maximize the informational power of plasma liquid biopsy as a tool for diagnosis, post-treatment follow-up, and as a prognostic tool in patients with GBM.

This is a prospective observational study. Patients with suspected brain tumors requiring 5-ALA fluorescence-guided surgery will be enrolled. Samples of plasma, serum, and urine will be collected at a minimum of two timepoints: once before 5-ALA administration (baseline, T1) and again 12 hours after administration (T2), when PpIX levels are expected to be highest. All sample collection and processing will occur in low-light conditions to prevent PpIX degradation. Samples will be stored at -80°C. Fluorometric analysis (Perkin Elmer Wallac 1420 Victor2 Microplate Reader) will be performed to measure PpIX fluorescence. Additionally, each patient will undergo a pre-operative MRI as per routine care to measure tumor volume, which will be correlated with fluorescence data.

Inclusion Criteria:

• Inclusion Criteria (Glioblastoma Patients):
• Patient aged 18 years or older
• Diagnosis of supratentorial glioblastoma at its first occurrence (Grade 4, WHO 2021), confirmed through histological analysis, in a brain area that is accessible for surgical removal.
• Ability of the patient to give informed consent.
• Suitability for surgery with fluorescence guidance using 5-ALA.

Inclusion Criteria (Other Brain Tumors):

• Patient aged 18 years or older
• Ability of the patient to give informed consent.
• Suitability for surgery with fluorescence guidance using 5-ALA.

Exclusion Criteria:

Exclusion Criteria (Glioblastoma Patients):

• Presence of other systemic tumors.
• Known allergic sensitivity or contraindications to gadolinium.
• Contraindications to MRI, such as the presence of non-compatible implanted devices.
• Significantly compromised renal function (eGFR <30 ml/min/1.73 m²), and/or patients undergoing dialysis.
• Conditions that contraindicate surgery with fluorescence guidance using 5-ALA.

Exclusion Criteria (Other Brain Tumors):

• Patients suffering from systemic tumors (besides the primary of the brain metastasis).
• Individuals with known allergies or adverse reactions to gadolinium.
• Individuals with contraindications for MRI, including those with implants not compatible with the procedure.
• Individuals with significantly reduced kidney function (eGFR < 30 ml/min/1.73 m²), or those undergoing dialysis.

30 Patients with brain tumors whose treatment course involves fluorescence-guided surgery 5-ALA.

The Sponsor (Fondazione IRCCS Istituto Neurologico Carlo Besta) is the owner of the data resulting from the study. All Investigators participating in the study should be made aware of such circumstance and not to disseminate information or data without the prior written consent by the Sponsor