Expression of fragile sites triggers intrachromosomal mammalian gene amplification and sets boundaries to early amplicons

A study was conducted of drug resistance induction through intrachromosomal mammalian gene amplification. The triggering of breakage-fusion-bridge cycles was correlated to induction of fragile site expression. The findings suggest that site-specific breaks triggered by fragile site inducers are responsible for the early features of intrachromosomal amplification. Fragile sites play a very important role in the amplification of at least some oncogenes during tumor progression.