Considerations for Cancer Genetics: Is Genetic Testing Right for You or Your Family?
By Alice Kerber, October 2, 2014
All cancers are genetic because the origin of the cancer involves changes at the basic gene level of cells. Some people have either genetic inheritance of a mutation (in the family) or exposure to cancer-inducing agents (carcinogens like ultraviolet light or cigarette smoke) and are at higher risk of developing cancer.
The human genome, or “master blueprint” of human genetic potential, consists of 23 pairs of chromosomes; one set from each parent. A chromosome is a single DNA molecule which holds the code for all characteristics and is contained in the nucleus of every cell.
Genes are the smallest functional units of the inherited information in DNA. Because every person inherits a set of chromosomes from each parent, different versions of genes, called alleles, may be present. Whether or not a trait is seen depends on if the trait is dominant or recessive. Dominant traits show up (are expressed) even if only one allele is involved. Recessive traits require both alleles to be involved in order to be expressed.
Most cancers are sporadic and caused by several acquired (not hereditary) changes or mutations. A small percentage (5-10%) of cancers are inherited and often passed from one generation to the next in an autosomal dominant pattern (every generation, men and women, are affected). Even having a mutation, however, does not guarantee that cancer will develop. Cancer is a multifactorial disease in which environmental factors and genes interact to cause its development.
Other “red flags” for hereditary cancer include: early age of onset, bilateral disease in paired organs (breasts, ovaries, etc.), multiple primary cancers in the same individual, multiple cancers across three generations, clustering of specific tumor types, and Ashkenazi Jewish heritage.
So, is genetic testing right for you and your family? Your health care provider and a genetic counselor or oncology nurse with specialization in genetics can help you decide. Ethical issues involve the impact of testing and results, who and when to share testing results with, and purpose for the testing information. Economic issues, including the cost of testing, can be significant – about $3,000 for a comprehensive series - as many insurance companies cover some portion of the testing, but not all. Practical issues include timing, treatment and surveillance decisions, and testing of children or siblings. Individual emotional responses can be unexpected and may result in a sense of guilt, or recognition that not everyone in the family wants the same information. All these issues warrant careful consideration. Only you can make the decision about testing with appropriate information, time, and support.
To learn more about genetic counseling and testing, visit these helpful websites:
About the Author
Alice Kerber, MN, APRN, ACNS-BC, AOCN, APNG is an advanced practice nurse in genetics and works as an oncology nurse specialist with Georgia CORE - the Center for Oncology Research and Education. You can reach Alice via email at firstname.lastname@example.org.