Why are the brca1 and brca2 genes considered to be tumor-suppressor genes?

brca1 and brac2 genes are considered as tumor suppressor genes because these produce tumor suppressor proteins and this tumor suppressor protein repair the damaged DNA, prevent the uncontrolled growth and suppress the cell growth and regulates the cell division.

When the tumor suppressor gene does not function properly cell cannot control their growth that leads to tumor formation and result in cancer.