Question

Biology.. What can the average age of diagnosis tell you about a mutation? (We are specifically talking about the BRCA1 and BRCA2 cancer-causing mutations... ages 44 and 46)

Answer 1

Well in those two genes, the mutation is commonly inherited from a previous generation. This would mean that the younger the age of diagnosis, the better the outcome would be for that patient. Since the age of mutation is later in these patients I would take that to mean it was a random mutation in these genes, not an inherited one. If they had inherited the mutation, cancer would more likely appeared at a younger age.

Cancer works through an accumulation of mutations that eventually lead to tumor growth. For cancer to develop, more that one gene usually needs to be mutated, causing numerous problems with the cell's inner processes.

Answer 2

I agree that inherited mutations mean greater risk of development of cancer at an early age. I think that these ages are young for sporadic disease so the mutations are probably inherited. You can read more about the genetics of breast cancer here:

http://www.breastcancer.org/risk/factors/genetics.jsp?gclid=CKfy0I_W4bACFUUhtAodESoPzQ