The p53 protein

One of the fly genes with a human counter part is p53,
a so-called tumor suppressor gene that when mutated allows
cells to become cancerous
The p53 gene is part of a molecular pathway that
causes cells that have suffered irreparable genetic damage
to commit suicide
It was identified that just as in human cells, fly cells
in which the p53 protein is rendered inactive, lose the ability
to self-destruct after they sustain genetic damage and instead
grow uncontrollably