Correlations between the combined deletions of chromosome 1p/19q and p53, phosphatase and tensin homolog deleted on chromosome ten and O6-methylguanine DNA methyltransferase protein expression in oligodendroglial tumors

Abstract

Objective To investigate the frequencies of chromosome 1p/19q co-deletion and its correlation with p53,phosphatase and tensin homolog deleted on chromosome ten (PTEN) and O6-methylguanine DNA methyltransferase (MGMT) protein expression in oligodendroglial tumors.Methods Samples of 68 oligodendroglial tumors (42 oligodendrogliomas and 26 anaplastic oligodendrogliomas) were collected.The 1p/19q status was detected by Fluorescence in Situ Hybridization (FISH) and the expression levels of p53,PTEN and MGMT protein were estimated semi-quantitatively by immunohistochemistry,then the correlations with I p/19q co-deletion were analyzed by t-test.Results The frequencies of 1p deletion,19q deletion,and 1p/19q co-deletion were 67.65％ (46/68),61.76％ (42/68) and 57.35％ (39/68)respectively in 68 oligodendroglial tumor samples.There was no obvious difference of 1 p/19q co-deletion between low-grade oligedendroglioma and anaplastic oligodendroglioma ( P ＞ 0.05 ).The frequency of 1p/19q co-deletion in frontal lobe (76.67％,23/30) was higher than that in temporal (45.00％,9/20) and the other lobes (38.89％,7/18) (P ＜0.05).There was no significant correlation between 1p/19q co-deletion,age and gender (P ＞ 0.05 ). p53 and MGMT protein expression were positively correlated with tumor grade,but PTEN protein expression negatively correlated with tumor grade in oligodendroglial tumors (P ＜ 0.05 ).Furthermore,there was a significant association between 1 p/19q co-deletion and low p53 and MGMT protein expression (P ＜ 0.05 ),but there was no significant correlation with PTEN protein expression in oligodendroglial tumors (P ＞ 0.05).Conclusion The combined deletion of chromosome 1 p/19q negatively correlates with the expression of p53 and MGMT protein in oligodendroglial tumors,which may be valuable in the diagnosis,treatment and prognostic prediction for oligodendroglial tumors. Key words: Oligodendroglial tumors; 1p/19q co-deletion; Fluorescence in situ hybridization; p53 protein; Phosphatase and tensin homolog deleted on chromosome ten; O6-methylguanine DNA methyltransferase