Breast Cancer
In the US and other developing countries, breast cancer is the most common form of cancer that affects women (~1:8). Breast cancer can affect men as well, although the disease is 100 times more common in women. The biggest risk factor after gender is age, as mutations have a larger chance of accumulating as we get older. The median age for individuals diagnosed with breast cancer is about 60 years old. Cancer cells can develop in various forms of breast tissue, with signs and symptoms that develop throughout time. Hereditary causes only account for 5-10% of all breast cancer cases.
Colorectal Cancer
Colorectal cancer affects about 1 in 24 Americans, and is the second-largest cause of cancer-related deaths for both men and women. Hereditary causes account for 10% of colon cancer cases. The most common cause of hereditary colorectal cancer is Lynch Syndrome, which results from mutations in the MLH1, MSH2, MSH6, PMS2, and EPCAM genes.
Ovarian Cancer
Ovarian cancer is relatively uncommon, though each woman has an equal chance of developing it. About 50 to 1 in 100 women are diagnosed with ovarian cancer in her lifetime, and is the fifth-highest cause of cancer-related deaths in women in the US. Hereditary causes have been estimated to account for 10% to 25% of hereditary ovarian cancers, with BRCA1 and BRCA2 implicated in 50-75% of those cases.
Prostate Cancer
Prostate cancer affects about 1 in 7 men, making it the second most-common type of cancer for men. This type of cancer can affect all men, regardless of family history of the disease. Age is the biggest risk factor, with the majority of prostate cancers being diagnosed in men over 65. Family history is another significant risk factor, as a man’s chances of being diagnosed doubles if someone in his close family (e.g. father, brother) has history of the disease. Men of African-American ancestry are also at higher risk, though there are no clear reasons as to why this is yet.
Uterine/Endometrial Cancer
In the US, uterine cancer affects around 1 in 38 women. Hereditary causes account for 5% of uterine cancer diagnoses, with Lynch syndrome being the most common form of the disease. Some risk factors associated are obesity, diabetes, and high blood pressure.
Lung Cancer
Lung cancer is another very common cancer that equally affects both men and women. Additionally, it is also the leading cause of death of those with cancer for both genders: about 25% of all cancer deaths are due to lung cancer. Smoking is the largest risk factor. Exposure to asbestos, radiation, and other carcinogenic compounds other common risk factors. Family history only increases the chance of getting lung cancer slightly, though individuals who have already been affected are at higher risk of developing another form of lung cancer. Genetic testing for lung cancers may be helpful in selecting targeted drugs specific to the type of lung cancer an individual has.
Skin Cancers
Skin cancer is the most common cancer in the US and most other countries, with incidence rates rising in the past few years. Major risk factors for developing skin cancer include overexposure to UV rays from both natural and man-made sources (sun, tanning beds) and family history. Individuals who have a personal history of skin cancer may be more susceptible to getting it again, which is why frequent testing or checkups may be recommended. Skin cancers are more common in older people, though younger individuals are most likely to be affected by skin cancer among all the other types of cancer.