Question

Explain how a mutation in the BRCA1 gene increases susceptibility to cancer.

1. Using your knowledge of gene expression, discuss why the penetrance of the susceptibility differs among different individuals.

2. Would you recommend that everyone undergo BRCA1 screening to prevent cancer development? Why or why not?

3. Would you recommend that everyone with a BRCA1 mutation undergo oophorectomy and/or mastectomy (ovarian/breast removal)? Explain.

4. Some women freeze their oocytes before undergoing oophorectomy. Are the future children protected from the effects of cancer?

Answer 1

1. Penetrance of susceptibility greately varies in individual depends on the severity of the phenotype in the allele, dominant or recessive etc., It is likely to be a function of the specific mutation(s) involved. The phenotype may be apparent in the later decades of life due to the health conditions.

2. It is recommended to screen for BRAC1 mutation which can be inherited and associated with development of breast and ovarian cancers.

3. Yes. Prophylactic oophorectomies and mastectomies reduce the incidence of cancer and subsequent metastasis when compared to chemo prevention or surveillance.

4. No. Freezing oocytes cannot prevent cancer incidence. Inherited diseases are associated with genes. Freezing only ensure the offspring from particular oocyte.