Abstract: It was unclear about the changes of chromosome const ruction in G2 phase arrested by teniposide (VM - 26) . To that , the premature chromosome condensation (PCC) assay was used in the present study. Hela cells were cultured for 24h with 5μg/ ml (7. 75μM) VM - 26. The PCC were induced by mixing the Hela cells with mitotic CHL cells in 50 %polyethylene glycol. It was revealed that the chromosome aberrations in G2 phase yielded by the VM - 26 were mainly in two types ,the irregular condensation of the chromosomes and the type of chromosome breaks . Such aberrations might response for the DNA st rand breaks , the chromatin breaks at the scaffold attachment s and especially the breaks across the chromosome cores , due to the inhibition of the VM - 26 on topoisomerase Ⅱ. Together with the result s of the cloning efficiency by measuring the Hela cells after cultured with the VM - 26 ,it was thought that the chromosome damages might result in the cell dath when they lost the DNA , or chromosome repair in G2 phase.

Key words: teniposide, antineoplastic agent s, premature chromosome condensation, chromosome damage.