Genetics of Breast CancerAutumn Gipson & Brianna Cantrell
Cancer Terminology
Type Of Cancer:
Location:
Carcinoma Epithelial Cells
Sarcoma Connective Tissue
Leukemia Circulatory / Lymphatic
Type of TumorsBenign tumours generally slow growing and enclosed in a fibrous capsule relatively harmless, although their location can make
them serious (such as a tumour located in the brain) not considered cancerous (they are not malignant) given names that usually end in "oma" (although
melanoma is a malignant skin cancer)Malignant tumours grow rapidly, invading neighbouring tissues can spread, to other sites of the body named using the type of tissue, cell type, and origin
Causes of Cancer Cancer can be caused by 3 factors:
› Gene Mutations Ex: mutations in BRCA1 &BRCA2 which can
lead to hereditary Breast & Ovarian Cancer› Environmental Factors
Ex: Tobacco, Radiation, Chemicals› Viruses
Ex: HPV – Cervical Cancer; Hepatitis B and C – linked to Liver Cancer
Types of Genes Which May Mutate to Cause Cancer:
Oncogene: a gene that, when mutated, disposes normal cells to change into cancerous tumor cells
DNA Repair Genes: DNA damages in frequently dividing cells are a prominent cause of cancer because mutations are more likely to occur
p53 Gene: if damaged or mutated, tumor suppression is severely reduced
Con’d. Tumor Suppressor Gene: a gene that
protects a cell from one step on to the path to cancer. When this gene is mutated, a loss or reduction in its function is caused, and the cell can progress to cancer
Breast Cancer Every woman has an 11% chance of
developing breast cancer during her lifetime
Most cases of breast cancer are sporadic; only 5-10% of all breast cancer cases are hereditary
Breast Cancer Cont’d.
The normal female breasts are paired structures that contain fat and glandular tissue designed to secrete milk. Cancer of the breast is one of the more common cancers in women. Risk factors: a family history of breast cancer, early age at first period, and late menopause.
Breast Cancer At Work….
The Result…
BRCA1 & BRCA2 Gene Are human genes belonging to a class
of genes known as tumor suppressors. These genes are linked to hereditary
breast and ovarian cancer The names BRCA1 and BRCA2 stand
for breast cancer susceptibility gene 1 and breast cancer susceptibility gene 2
BRCA1 Gene The BRCA1 gene, when properly
functioning, can help prevent breast cancer, but abnormal variations can significantly increase the risk of developing breast cancer. Females born with the affected gene face a 50-80 per cent risk of contacting breast cancer and a 40-60 per cent chance of developing ovarian cancer.
BRCA1
BRCA2 Gene There are more than 800 mutations in the BRCA2 gene
(Many associated with increased risk of breast cancer). Many BRCA2 mutations insert or delete a small
number of nucleotides in the gene, disrupting protein production
This results in an abnormally small, nonfunctional version of the BRCA2 protein.
Researchers believe that the defective BRCA2 protein is unable to help repair damaged DNA or fix mutations that occur in other genes. As these defects accumulate, they can allow cells to grow and divide uncontrollably and form a tumor.
Ovarian Cancer At Its Worst…
In Their Harmful State… Harmful BRCA1 mutations may also
increase a woman’s risk of developing cervical, uterine, pancreatic, and colon cancer.
Harmful BRCA2 mutations may additionally increase the risk of pancreatic cancer, stomach cancer, gallbladder and bile duct cancer, and melanoma.
Here’s Some Good News.. Even though these genes are genetic, not
every woman who are in a family known for breast cancer and/or ovarian cancer carries a harmful BRCA1 or BRCA2 mutation
Not all breast cancers are due to harmful mutated genes
Additionally, not every woman who has a harmful BRCA1 or BRCA2 mutation will develop breast and/or ovarian cancer.
It’s Not Only BRCA Genes.. Mutations in several other genes,
including TP53, PTEN, STK11/LKB1, CDH1, CHEK2, ATM, MLH1, and MSH2, have been associated with hereditary breast and/or ovarian tumors.
However, the majority of hereditary breast cancers can be accounted for by inherited mutations in BRCA1 and BRCA2
Current Solutions If At Risk…
Surveillance Prophylactic Surgery Chemoprevention
No Genetic Discrimination Allowed
Genetic discrimination occurs when people are treated differently by insurance companies or employers because they have a gene mutation that increases their risk of a disease, such as cancer.
However, in 2008, GINA was enacted to protect U.S. citizens against discrimination based on their genetic information in relation to health insurance and employment
The law does not cover life insurance, disability insurance, and long-term care insurance. In addition, the law does not cover members of the military.
Looking Ahead… Many research studies are being
conducted to find newer and better ways of detecting, treating, and preventing cancer in BRCA1 and BRCA2 mutation carriers. Additional studies are focused on improving genetic counseling methods and outcomes. Our knowledge in these areas is evolving rapidly