(Harry Kochat, BioNumerik Pharmaceuticals)
Clinical statisticians and experimentalists indeed suggested that most common cancers have considerable dependencies to variable level of heredity risk. In general, if there is a history of cancer in your family, you may have an increased chance of getting the disease. Five to ten percent of cancer cases are the results of altered genes that can be transmitted between generations Members of such families have a greater lifetime risk of developing cancer than the general public. Multiple cancers in one individual, cancer in more than one generation or in multiple members of a family, and early age of onset are some of the indicators of hereditary cancer. Most common cancers are suggested to have considerable dependencies to variable level of heredity risk. However the risk management of inherited cancers in human subjects is not fully understood due to its complexities. Some ethnic groups apparently develop immunity against certain specific cancers. For example, chronic lymphocytic leukemia is extremely rare among Asians; Ewing's sarcoma, skin cancers, and testicular cancer are very rare among African Americans.
New methods in molecular biology have been used to identify several human cancer genes and to reveal a new class of cancer genes, called tumor suppressor genes or antioncogenes. These genes normally function by inhibiting the development of cancer. However, when they are damaged they lose their protective effect and cancer arises with greater frequency. The first such inherited cancer susceptibility gene to be discovered was that for retinoblastoma (RB1), a malignant eye tumor which occurs in children.
Public awareness is a crucial factor in the case of hereditary cancers. Mismanagement of public information can be mentally lethal and painful. Such inaccurate information and unnecessary manipulations can cause significant impact to oneís life. Several accurate risk assessment and guidelines for such early detection is available today, since very few people actually have a hereditary cancer syndrome in their family.
What are genes?
Genes are packages of genetic information that dictate how we grow physically and which one of the human behavior should supercede and how each cells of our body will function. Each gene determines a specific characteristic about us. Each person has two copies of about 100,000 genes. Sometimes a change occurs in a gene, which stops the gene from working properly. Such a change is called a mutation. If a person has a mutation in a cancer gene, then that gene does not work properly and there is a higher chance of developing cancer.
In several cases, inheritance of a gene which can lead to the development of cancer can be determined by individual DNA testing. In addition to the conventional DNA testing and PCR mapping more advanced genetic testing protocols are also available in this modern era. Since genetic information can be a delicate issue, you will be offered education and counseling about the benefits, possible risks and limitations of testing to help you decide whether to be tested. Due to the intensity of information concealed in genetic and DNA assay, all the information recorded will be kept confidential and any release of such information is restricted to a prior written consent of the person who is tested or the personís beneficiary.
Advantageous of genetic testing include:
When do we suspect cancer is hereditary?
The risk of hereditary cancer is significant when close family members have the same type of cancer on the same side of the family these cancers are seen in a number of generations and often these cancers are diagnosed at a young age more than one type of cancer occurs independently in the same person cancer occurs in the less commonly affected sex (e.g. breast cancer in men) .
Will cancer always develop if a person carries a mutated gene?
We get our genetic information from both of our parents. Everyone is born with two copies of each gene. One copy comes from the mother, the other from the father. If a person carries a mutation in one of their cancer genes, they will have a 50% chance of passing the mutated gene to each child. Not all persons with a mutation in a cancer gene will develop cancer. There are many factors that may influence whether a person develops cancer. If a person has a mutation in a cancer gene, they will have an increased chance of developing hereditary cancer.
Cancers linked to a single inherited genetic abnormality include:
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