Posts Tagged ‘risk’

Breast Cancer: Symptoms, Causes, Genetics and Genetic Testing

May 11, 2010

Breast cancer is defined as cancer that originates in the breast cells. Women are 100 times more likely to develop it than men. It is the second most common form of cancer after lung cancer. Every year about 200,000 American women are diagnosed with breast cancer. It killed half a million people in 2005.

Breast cancer can spread through the lymphatic system or blood vessels to other parts of the body. This spread is referred to as metastasizing. It can metastasize to the lungs, brain, liver or bones.

There are non-specific and specific symptoms. Non-specific means that they could be symptoms for some other condition. Some non-specific symptoms include:

  • bone and joint pain
  • chills
  • discharge from one nipple
  • fever
  • jaundice.

Some specific symptoms include change in the size or shape of the breast or nipple and a lump in the breast or the lymph nodes in the armpit and/or collarbone

Inflammatory breast cancer occurs when breast cancer cells enter the small lymph vessels next to the skin. Symptoms include:

  • orange peel texture of the skin
  • pain
  • redness
  • swelling
  • warmth.

Paget’s disease of the breast also manifests itself in the skin and resembles eczema. Symptoms may include:

  • discharge
  • itching
  • lump
  • mild flaking of the skin around the nipple
  • redness
  • sensitivity
  • tingling.

Causes of Breast Cancer

Breast cancer stems from a combination of hereditary and environmental influences. People who have a family history with multiple cases of breast or ovarian cancer are at higher risk of getting breast cancer. Breast cancer is more common if one has an Ashkenazi (Eastern European) Jewish background. It usually occurs sporadically and is not inherited. Some risk factors include:

  • age
  • alcohol intake
  • childbearing
  • environmental factors like radiation and tobacco use
  • high fat intake
  • hormones
  • obesity
  • sex.

Genetics of Breast Cancer

About 5-10% of those diagnosed have a hereditary form of breast cancer. If a person inherits a mutation in the breast cancer 1 (BRCA1) or breast cancer 2 (BRCA2) genes, she is at higher risk of developing breast cancer. It is rare to inherit a mutation. Only one in 1000 has a mutation in one of these genes.

People who have the mutation may get cancer or may lead a long healthy life. Having a mutation does not guarantee the individual will develop cancer. About 13% of the population develops breast cancer. Those with a mutation in either of these genes are three to seven times more likely to get it.

How Genetic Testing Is Done for Breast Cancer Patients

Genetic testing looks at sequences of DNA to identify changes. The sequence of DNA has been determined for healthy people. If there is a mutation in a gene, it can make a person more susceptible to certain diseases. Certain inherited conditions have been linked to mutations in certain genes. Genetic testing is the comparison of the sequence of sample DNA to the agreed upon sequence for a normal gene to identify these risks.

Genetic testing for breast cancer is only performed on people who are at high risk of getting cancer. This blood test identifies the presence of mutations in the BRCA genes. A breast cancer genetic testing lab determines the patient’s risk of getting cancer. Genetic counseling is included in this test to make sure people are informed of their risk and options for the future.

Progress toward a Cure

Treatment for breast cancer today relies heavily on surgery, chemotherapy and radiation. Gene therapy is one option of curing breast cancer. It is not yet possible, but eventually doctors will be able to fix the mutations in the genes. Research continues to search for more genes that influence a person’s risk of developing breast cancer.

Some ways to prevent breast cancer include:

  • Chemoprevention – Some medications, such as tamoxifen, decrease one’s chance of developing cancer.
  • Mastectomy – Preventative removal of breast tissue reduces the risk of cancer by 90%.
  • Surveillance – More frequent self-exams, clinical exams, MRI’s and mammograms discover cancer earlier.

Prostate Cancer: Biology, Genetics, Prevalence

May 11, 2010

Prostate cancer can only occur in men because the prostate is a gland which exists in the male reproductive system. Prostate cancer detection begins with screening for prostate specific antigen (PSA). Detection occurs less often when symptoms develop or by physical examination. Prostate cancer diagnosis is confirmed by biopsy. Risk factors include age, ethnicity, family history and diet.

Prostate cancer is the most common cancer in American men. It can be painful, make urinating difficult and cause erectile dysfunction. Men who are at average risk of prostate cancer have a 14% chance of developing prostate cancer by the time they are 80 years of age. Prostate cancer is the second leading cause of cancer death in men. Many men develop prostate cancer, do not have any symptoms and die of other causes related to old age.

Biology of Cancer

Cancer occurs when genes mutate and do not produce the correct regulatory proteins which normally control cell functions. Cells then multiply out of control. Cancer can spread to other parts of the body, such as bones and lymph nodes. Genes can mutate before a person is born. This is considered to be hereditary. This type of cancer can be inherited by offspring in future generations. Genes can also mutate during a person’s lifetime. The cells derived from this line would then be immortal.

Prostate Cancer Genetics

Most prostate cancer is sporadic, so 75% of individuals with prostate cancer mutated genes after birth. Only 5% of men inherit prostate cancer. The remaining 20% develop familial prostate cancer, which means that a combination of environmental and shared genes resulted in cancer.

Genetics has been implicated in the development of prostate cancer. Every cell contains two copies of each gene; one copy originates from the mother and one from the father. When prostate cancer is inherited, it follows an autosomal dominant inheritance. This means that the mutation only has to occur in one copy of the gene for the individual to be at higher risk of developing cancer. Each child has 50% chance of inheriting the mutation causing prostate cancer from a parent who has the mutation.

The only way a person can know if they are at high risk of having a genetic mutation is genetic testing. Since there is no genetic test for prostate cancer, one must rely on family history. If a man has a strong family history of prostate cancer, he can participate in prostate cancer research to determine what the genes are that are correlated with it.

Prostate cancer risk factors include mutations in several genes. A gene on chromosome 17 is associated with increased risk of prostate cancer.  Research must be continued to verify these findings to determine if they can be used for genetic testing in the future. Several other mutated genes have been identified as being responsible for increased likelihood of developing prostate cancer.

Prevalence of Prostate Cancer

Rates of prostate cancer vary widely throughout the world. It is least prominent in South and East Asia, more common in Europe and most common in the United States. In 2008, about 186,000 men in the US will be diagnosed with prostate cancer. It normally develops in men over 50 years old. An estimated 28,000 deaths will occur from prostate cancer. Although the incidence of prostate cancer is decreasing overall, black men are twice as likely to develop this cancer as white men.

Progress toward a Cure

Prostate cancer prevention may be in the near future. Men can determine their risk factor through their family history and attempt to control certain environmental and lifestyle factors. These factors include a balanced diet, healthy weight, exercising, limiting alcoholic beverages and avoiding tobacco products. Eventually research will determine which genetic mutations are correlated with prostate cancer.