The Correlation Between 1p/19q Codeletion, IDH1 Mutation, p53 Overexpression and Their Prognostic Roles in 41 Turkish Anaplastic Oligodendroglioma Patients.

Aim: To observe the correlation between 1p/19q codeletion, isocytrate dehydrogenase-1 (IDH1) mutation and p53 protein overexpression and their prognostic value in Turkish anaplastic oligodendroglioma patients who were treated with adjuvant radiotherapy and temozolomide chemotherapy.

Material And Methods: We retrospectively evaluated 41 patients who were diagnosed as anaplastic oligodendroglioma. Thirty-five patients received standard radiotherapy. Twenty-six patients received standard temozolomide chemoterapy concurrent to radiotherapy.

Results: Chromosome 1p/19q codeletion was observed in 19 of 41 patients (46%) via Fluorescent In Situ Hybridisation (FISH) technique. Twenty-six patients (63%) showed positive immunoreaction with anti-IDH1 antibody. Six patients (15%) showed positive immunoreaction with anti-p53 antibody. A statistically significant correlation was determined between chromosome 1p/19q codeletion and IDH1 mutation (p < 0.0001). The patients who had tumors with chromosome 1p/19q codeletion and p53 overexpression were mutually exclusive. The mean estimated Progression Free Survival (PFS) of the patients who had tumors with chromosome 1p/19q codeletion and/or IDH1 mutation was determined to be significantly longer than that of the patients without these genetic changes, regardless of the treatment modality (p=0.006, p=0.004). PFS of the patients who received adjuvant chemotherapy and whose tumors had chromosome 1p/19q codeletion or IDH1 mutation was significantly longer than that of the patients without these genetic changes (p=0.001, p < 0.0001).

Conclusion: Chromosome 1p/19q codeletion and/or IDH1 mutation are favorable prognostic factors in anaplastic oligodendroglioma patients, in terms of PFS.