Cancer is a genetic disease. It begins with the mutation of a single gene within a specific cell in the body. The damaged cell reproduces into multiple damaged cells which can accumulate into a tumor and spread into other parts of the body.
We receive our genetic makeup from our parents, so knowing your family's history of cancer is important. The National Comprehensive Cancer Network (NCCN) recommends referral to a genetics expert for evaluation of cancer patients and people if they meet any of the following criteria.
Anyone with a personal history of any of the following:
Anyone with a family history of one or more of the following:
- A blood relative with a known mutation in a gene that increases cancer risk
- A blood relative with two or more primary breast cancers
- Two or more relatives with breast cancer on the same side of the family with at least one diagnosed before age 50
- A blood relative with ovarian cancer
- A close blood relative with breast cancer before age 45
- A blood relative with male breast cancer
Anyone with a family history of three or more of the following, especially if any of the cases are diagnosed before age 50:
- Pancreatic cancer
- Prostate cancer
- Adrenal cancer
- Brain tumors
- Uterine cancer
- Thyroid cancer
- Kidney cancer
- Diffuse gastric cancer
- Colon cancer
- Anyone of Ashkenazi Jewish ancestry is at a higher risk of breast, ovarian and pancreatic cancer.
- Non-Hispanic white and African American women are at the highest risk of breast cancer.
- For unknown reasons, prostate cancer is more common in African American men.
Cancer Syndromes are genetic disorders that predispose carriers of certain genes to different types of cancer. Oftentimes, theses cancers develop when genes that normally control how cells divide and reproduce mutate; allowing for uncontrolled cellular reproduction. Inheriting a gene associated with a cancer syndrome does not guarantee that the carrier will develop that cancer, but it does increase his or her likelihood of developing the associated cancer(s).
Familial Adenomatous Polyposis (FAP)
Familial adenomatous polyposis (FAP) is a disorder that causes small growths called polyps in the colon and rectum. These growths are benign initially, but become cancerous with time unless they are removed. A mutation in the APC gene prevents the cells in the colon and rectum from growing and functioning regularly, which results in abnormal overgrowth.
Hereditary Breast-Ovarian Cancer Syndrome
Hereditary breast-ovarian cancer syndrome is a genetic condition passed down along family lines that predisposes women to an increased risk of developing breast and ovarian cancer. It is characterized by mutations of the BRCA1 and BRCA2 genes which, when healthy, help control cellular division and reproduction. Damaged BRCA1/2 genes allow cells to grow uncontrollably and accumulate into tumors. BRCA1/2 mutations also increase the risk of prostate, pancreatic and male breast cancer.
Li-Fraumeni syndrome is a rare predisposition to cancers of the breast, adrenal glands and ovaries, as well as leukemia and sarcoma. The syndrome usually presents symptoms in children and young adults. It’s marked by mutations of the TP53 and CHEK2 genes, which both serve as tumor suppressors by inhibiting abnormal cell growth and overgrowth. Mutations in these genes prevent normal function and allow for tumor growth.
Hereditary Nonpolyposis Colorectal Cancer (Lynch Syndrome)
Lynch syndrome increases the risk of cancers of the digestive tract, including the colon, rectum, stomach, small intestine, liver and gallbladder ducts. It can also cause cancers of the urinary tract, brain and skin. In women, Lynch syndrome can also increase the likelihood of developing ovarian and endometrial cancer. The MLH1, MSH2, MSH6, PMS2 genes prevent mistakes in DNA replication, however, mutations in these genes allows for DNA mistakes.
Multiple Hamartoma Syndrome (Cowden Syndrome)
Cowden syndrome is characterized by non-cancerous growths called hamartomas that appear in the skin, breast, thyroid, colon, intestines and inside of the mouth. These growths are the result of a mutation in the PTEN gene, which is a tumor suppressor. While the initial growths are not cancerous, Cowden syndrome is associated with increased risk of cancer, including breast, thyroid, uterine and endometrial.
Multiple Endocrine Neoplasia Type 1 (Wermer Syndrome)
Multiple endocrine neoplasia type 1 is characterized by tumors on the organs and tissue of the endocrine system, which includes the pituitary gland, pancreas, ovaries, testicles and thyroid. These organs and glands produce hormones that regulate bodily functions ranging from growth and development to sleep and mood. The MEN1 gene helps produce a protein called menin that acts as a tumor suppressor in the endocrine system. Mutations in the MEN1 gene can lead to uncontrolled cellular growth in the endocrine system, which can become cancerous tumors.
Multiple Endocrine Neoplasia Type 2
Multiple endocrine neoplasia type 2 typically causes a form of thyroid cancer called medullary thyroid carcinoma, but it can cause other cancers of the endocrine system as well. When healthy, the RET gene signals cells to divide at a safe and normal rate. Mutations in this gene can cause accelerated, uncontrolled cell growth, which can lead to tumors of the endocrine system.
Nevoid Basal Cell Carcinoma Syndrome (Gorlin Syndrome)
Gorlin syndrome is a condition that can affect the skin, eyes, nervous system, endocrine system and bones. The most common symptoms are cysts in the mouth and areas of basal-cell skin cancers. These growths appear in adolescence or young adulthood and are usually not life-threatening, but should be treated. Gorlin syndrome is linked to variations in the PTCH1 gene, which helps maintain healthy cell division and reproduction.
Peutz-Jeghers syndrome is a rare genetic disorder that causes benign growths called hamartomatous polyps in the intestines and stomach. Symptoms of Peutz-Jeghers can be present in children, with small, flat, dark-colored spots forming on the lips, eyelids, nostrils and anus. Most of the time, these growths can be attributed to a mutation of the STK11 gene, which normally keeps cells from dividing and multiplying abnormally. People with Peutz-Jeghers syndrome have a high chance of developing cancer.
Retinoblastoma is an eye cancer that usually appears in children under age 5 and generally affects one eye, although both eyes may be affected. The cancer develops because of problems with the RB1 gene, which controls cell growth. Mutations in this gene allow cells to grow uncontrollably, leading to a whiteness in the pupil called leukocoria, which is visible in flash photography. If treated early, retinoblastoma can be cured. If left untreated the cancer can spread to other parts of the body and become life-threatening.
Von Hippel-Lindau Syndrome
Von Hippel-Landau syndrome is a disorder that causes abnormal blood vessel and cyst growth in the eyes, brain, spinal cord, adrenal glands and other parts of the body. Although these growths are usually non-cancerous, they can become cancerous. Depending on location, they can cause serious complications including deafness, vision loss, weakness and loss of coordination. The growths are a result of a mutation in the VHL gene, which keeps cells from dividing uncontrollably.
Precision Medicine is treatment that is tailored to the individual patient. For cancer patients, tumor genotyping - examining the individual's DNA for gene variants - is allowing for personalized therapies.