Detection Of Chromosomal Genomic DNA Imbalance In Medulloblastoma By Comparative Genomic Hybridization

Objective:To investigate the relationship between chromosomal genomic DNA imbalance in medulloblastomas(MDs)and,patients' gender and age.The research aimed to identify the useful molecular genetics markers which were helpful to pathological diagnosis,differentiation,and evaluations of biological behaviour and prognosis.The molecular genetics clues were also provided for finally understand the development and progression of these tumors.Methods:A total of 16 archived paraffin-embeded tissue samples of MDs were obtained at the neuropathology department of Tianjin medical university general hospital from 2000 to 2008.Their pathological diagnosis was confirmed again.Pan-genomic DNA of all the tumors was extracted from formalin-fixed and paraffin-embedded tissue section.The reference Pan-genomic DNA was extracted from leukocytes of normal male donors.Both of the DNAs were labeled by nick translation technology.The gains and losses of chromosomal genomic DNA in 16 MDs were analyzed using comparative genomic hybridization.Results:The gains and(or)losses were found in 15(93.8%)of the 16 cases.There was not significant difference(P>0.05)between the total gains(62.5%,10/16)and losses(68.8%,11/16).Both of their differences have also no significance between different age and gender groups(P>0.05).The ratioes of single-,two-,three-and multi-chromosome genomic DNA imbalance were 20.0%(3/15),26.7%(4/15),6.6%(1/15)and 46.7%(7/15)respectively.Eleven gain zones(+5q,+6q,+7q,+11q,+15q,+17p,+17q,+19q,+20q,+21 q,+Xp)and twenty-five losse zones(-1p,-1q,-2p,-2q,-3q,-4p,-6p,-6q,-8p,-8q,-10p,-10q,-11p,-14q,-16p,-16q,-17p,-18p,-18q,-19p,-19q,-20p,-20q,-Xp,-Xq)were detected in these tumors.+7q(37.5%,6/16),+17q(37.5%,6/16),-14q(31.3%,5/16)and-10q(18.8%,3/16)were the most frequent,but-14q only occurred in the cases of>10-year-old.Conclusion:Most MBs have chromosomal genomic DNA imbalances.The frequent imbalances zones are mainly at the long arms of some chromosomes.+7q,+17q,-14q and-10q correlate closely to development of the tumors.-14q is important factor to result in MBs of>10-year-old group.MB has possibly different molecular genetics subtype.