Study Of Loss Of Heterozygosity Of Chromosome 1p/19q In Oligodendroglioma And Astrocytoma And Its Clinical Significance

Objective:To study the status of loss of heterozygosity(LOH)of chromosome lp/19q in oligdendroglioma, and to analysis the relationship with its clinical features, as compared with astrocytoma. Methods:Eight-one cases of subtypes and grades of gliomas were investigated, including 23 low-grade oligodendrogliomas,20 anaplastic oligodendrogliomas and 38 different grades of astrocytoma paraffin-embedded tissue. Loss of heterozygosity(LOH)of chromosome lp/19q was detected by fluorescence in situ hybridisation(FISH). Results:In 81 cases of oligodendroglioma and astrocytoma,5 cases(3 cases of astrocytoma and 2 cases of oligodendroglioma)were polyploid of lp/19q. In the remaining 76 tumors, the positivity rate of 1p loss,19q loss and 1p/19q loss was 59. 1%,63.6% and 54.5%respectively in 22 cases of low-grade oligodendroglioma, while it was 73.7%,73.7%and 58.5% respectively in 19 cases of anaplastic oligodendroglioma. There was no statistics difference of LOH of 1p,19q, 1p/19q between low-grade oligodendroglioma and anaplastic oligodendroglioma(P=0.326, P=0.491, P=0.577). While it was 14.3%,20% and 14.3% respectively in 35 cases of astrocytomas. There was statistics difference of LOH of lp/19q between oligodendrogliomas and astrocytomas(P=0.000). The positivity rate of lp/19q LOH was higher in younger patients(18～60 years old)than in older patients(>60 ears of age)and teenagers(<18 years old)(P=0.007). The positivity rate of 1p/19q LOH was higher in frontal lobe and occipital lobe than in other lobes(P=0.018). The survival time of patient with 1p/19q LOH was longer than those without 1p/19q LOH or only with 1p LOH(P=0.005, P=0.035). And astrocytomas in the molecular genetics specificity does not exist corresponding clinical significance. Polyploid of 1p/19q in 5 cases, including 3 cases of astrocytoma and 2 cases of oligodendroglioma. Conclusion:The lp/19q LOH was a common event in oligdendrogliomas, but not in astrocytomas. LOH of chromosome lp/19q was a distinct molecular abnormality in oligodendrogliomas. There wewe correlations between 1p/19q LOH and patient age and tumor location. The survival time of patients with lp/19q LOH was longer than those without this molecular abnormality or only with 1p LOH. polyploidy of 1 p and/or 19q was more common in astrocytoma subtypes, which may be associated with composition of the astrocytomas.