Final answer:
BRCA genes serve as tumor suppressor genes, repairing damaged DNA and preventing cell division of damaged DNA.
Step-by-step explanation:
The role of BRCA genes is to serve as tumor suppressor genes. When functioning normally, these genes help to prevent the growth of cancer cells by repairing damaged DNA and preventing cell division of damaged DNA. However, if the BRCA genes are mutated, they may not be able to effectively repair DNA damage, increasing the risk of developing cancer.