Off topic:what is the evolutionary importance of existance of cancer gene(s) in other animals than human

Question

[Farbod]

Hi,

Why other animals same as zebrafish has for example the BRCA1 gene ( that in human is responsible for most case of breast cancer) in their genome?

what is its evolutionary importance ?

and by comparing the human BRCA1 and zebrafish BRCA1 with each other (for example by aligning these two sequence) what can we realize ?

Thanks