Nanoparticle-Based Receptors for Catecholamine Profiling in Diagnosis and Prognosis of Neuroblastoma

Neuroblastoma is the most common extracranial solid tumor of childhood, and urinary catecholamine metabolites, in particular homovanillic acid (HVA), are established diagnostic biomarkers. These metabolites are routinely quantified by liquid chromatography-tandem mass spectrometry (LC/MS-MS), a sensitive method that requires lengthy sample preparation. This thesis examined whether 1H nuclear magnetic resonance (NMR) spectroscopy, which needs only minimal sample preparation but is less sensitive, can provide comparable analytical information on urinary HVA. The study was retrospective analytical comparison. Archived 1H NMR spectra of 90 anonymized urine samples from the Istituto Giannina Gaslini (30 high-risk, 30 low-risk, and 30 control) were reprocessed in MestReNova. Baseline-corrected peak intensities of the HVA aromatic proton and of creatinine were extracted and compared with the hospital LC/MS-MS reference values by regression through the origin. Group distributions were assessed with a control derived threshold (mean + 3 SD), and the aromatic region of the spectra was analysed by principal component analysis (PCA). Creatinine was measurable by NMR in 70 of the 90 samples and HVA in 67; both were available in 61. Where measurable, the NMR response agreed well with the LC/MS-MS values, with coefficients of determination of 0.92 for creatinine and 0.94 for HVA (both p < 0.0001) and no concentration dependent bias in the residuals. In the subgroup analysis, agreement was strong in the two patient groups (HVA R2 = 0.98 high risk, 0.89 low risk) but weaker in the controls (R2 = 0.66), where HVA levels lie close to the detection limit. With the control derived threshold, 20 of 23 high risk and 15 of 25 low risk samples exceeded the LC-MS/MS cut-off while no control sample did; even so, high and low risk groups overlapped and were not separated by either variable. PCA of the aromatic region (45 samples: 26 high risk, 19 low risk) separated the two risk groups along the second component, which explained 8.4% of the variance, with an in sample sensitivity of 81% (21/26), specificity of 79% (15/19) and accuracy of 80% (36/45); the single-signal comparisons did not show this distinction. NMR did not detect HVA in every sample and did not resolve VMA, so it cannot replace LC-MS/MS. Where the signal was measurable, however, it reproduced the reference values and carried spectral information related to risk group. Rather than a replacement for mass spectrometry, NMR is better regarded as a complementary method that can be used alongside it; its much shorter sample preparation makes it attractive, and the approach is worth pursuing in a larger, standardized cohort.