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.