IDH1 single nucleotide polymorphism improves progression free survival in patients with IDH mutated grade II and III gliomas.

Background: A synonymous single nucleotide polymorphism (SNP) is a substitution of a single base that does not modify the primary amino acid sequence but could influence protein function. In patients with brain tumors, the incidence of the silent SNP IDH 1 105GGT (rs11554137) is three times higher than the normal population.

Methods: Our aim was to investigate the prognostic role of the IDH 1 105GGT SNP. We selected only patients with diagnosis of IDH grade II or III mutated glioma. Additional inclusion criteria were: complete clinical data and adequate tumor samples for IDH 1 or 2 sequencing.

Results: 71 patients with grade II and III IDH-mutated glioma have been evaluated. Nine of 71 patients (12.7 %) presented the SNP . Patients with SNP had a longer Progression Free Survival (PFS - 47.3 months vs Not reached; p = 0.015). The SNP (HR 0.240; 95 %CI 0.074-0.784, p = 0.018) was confirmed as an independent prognostic factors in multivariate analysis.

Conclusions: Patients with IDH1 or 2 mutated grade II and III glioma presenting the SNP had longer PFS regardless adjuvant treatment received and extension of primary surgery. A validation is warranted to confirm our preliminary results.