Final answer:
Tumor suppressor genes, including BRCA genes, primarily function in DNA repair, playing a pivotal role in preventing cancer by halting the cell cycle for repairs or inducing cell death when damage is irreparable. The correct option is B.
Step-by-step explanation:
The primary function of tumor suppressor genes, such as the BRCA genes involved in breast cancer, is DNA repair. These genes play a crucial role in maintaining the integrity of a cell's genetic material. Tumor suppressor genes work as part of the cell's quality control mechanisms to prevent cancer development.
When normal function is present, these genes help to repair DNA damage, halt the cell cycle to prevent the passing on of mutations, and induce apoptosis if the damage is irreparable.
The p53 protein is an example of a tumor suppressor gene product that acts as a transcription factor in response to cellular stress or DNA damage, aiding in repair or triggering cell death if the damage is too extensive.