1. The histogram below shows the total estimated new breast cancer cases diagnosed in 2003. Histogram

2. The results in this table below are from a 2007 study investigating BRCA mutations in women diagnosed with breast cancer. All of the women in the study had a family history of breast cancer.

BRCA Mutations in Women Diagnosed with Breast Cancer

BRCA1 mutation

BRCA2 mutation

No BRCA mutation

Total

Number of patients

89

35

318

442

Average age at diagnosis

43.9

46.2

50.4

Preventive mastectomy*

6

3

14

23

Preventive oophorectomy*

38

7

22

67

Number of deaths

16

1

21

38

Percent died

18

2.8

6.9

8.6

*A mastectomy is the surgical removal of one or both breasts, either partially or fully. An oophorectomy is the surgical removal of an ovary or ovaries.

Things to address in your summary essay:

Describe how mutations lead to genetic variations.
Which appears to be more dangerous: the BRC1 or BRC2 mutation?
Analyze a woman’s risk of dying of cancer if she carries a mutated BRC1 gene.
How do heredity and inheritance relate to the data presented in these charts?
What data would you need to see in order to draw conclusions about the effectiveness of preventive surgeries?
What does the age at diagnosis tell you about the mutation?
Explain how breast-cancer genes are still present in the population, despite cancer-related surgeries and deaths.