Significance of molecular genetic alterations of chromosome 1p/19q in differential diagnosis of oligodendroglioma and astrocytoma

Objective To study the significance of molecular genetic alterations of chromosome 1p/19q in differential diagnosis of oligodendroglioma and astrocytoma.Methods Molecular genetic alterations of chromosome 1p/19q were detected with fluorescence in situ hybridization in 63 patients with oligodendroglioma or astrocytoma.Results Polyploid of 1p/19q was in 5 cases(3 cases of astrocytoma and 2 cases of oligodendroglioma).Loss 1p/19q heterozygosity was in 58 cases(41 cases oligodendroglioma and 17 cases of astrocytoma).The loss rates of chromosome 1p,19q and 1p/19q were 65.9%,68.5% and 58.5% respectively in 41 cases of oligodendroglioma,and were 17.6%,29.4% and 17.6% respectively in 17 cases of astrocytoma,which showed significant differences between two groups(P=0.001,P=0.006,P=0.004).Twenty-one cases(87.5%) and 9 cases(52.9%) had typical oligodendrocyte morphological characteristics in 24 oligodendroglioma cases of 1p/19q heterozygosity loss and 17 oligodendroglioma cases of no 1p/19q heterozygosity loss resprctively,which showed significant differences between two groups(P=0.014).Conclusion Loss rate of 1p/19q heterozygosity is higher in oligodendroglioma than that in astrocytoma,and more likely to occur in oligodendroglioma with typical histological features.Polyploidy of chromosome 1p/19q is more common in astrocytoma subtypes.