Does Genomic Instability Cause Cancer?

This has been a pretty old question.  Cancer cells are notorious for having lost control of their genomes, but is this a symptom or a driver of cancer?  A recent study with fruit flies indicates it's a driver.

Note that in addition to causing mutations in DNA in the "hit" cell, ionizing radiation also causes genomic instability whose effects include mutations, chromosome aberrations, aneuploidy and micronuclei, in cell daughters several generations after the "hit".