How Genetics Impact Cancer Diagnoses

How Genetics Impact Cancer Diagnoses

An overview of how genetics impacts the likelihood of a cancer diagnosis, and how embryo screening can mitigate this risk

Written by Maria Katz, MS, CGC
Reviewed by Xiaoli Du, PhD, FACMG, DABMGG, CGC,CGMBS

Dr. Du is American Board of Medical Genetics and Genomics (ABMGG) certified geneticist. With a passion for precision medicine, she leverages cutting-edge molecular genetics and cytogenetics technology to improve outcomes for individuals affected by genetic conditions. Dr. Du has nine years of clinical genetic diagnosis experience in both the public and private sectors.

What Causes Cancer?

Cancer is a disease where the body's cells start to grow and multiply in an uncontrolled way. These abnormal cells can form tumors or masses, disrupting the normal functioning of organs and tissues. 

According to the World Health Organization, cancer affects millions of adults worldwide each year. The causes of cancer can be attributed to a combination of genetic and environmental factors. While the majority of adult cancer cases occur sporadically without a clear hereditary cause, a percentage is associated with genetic mutations that individuals are born with, predisposing them to cancer.

Cancer can affect any part of the body, however some cancers are more likely to be related to a hereditary cause.

Hereditary causes of cancer refers to individuals who are born with specific gene mutations that increase their susceptibility to developing cancer. Certain genes play a role in regulating cell growth and behavior, and mutations in these genes can elevate the risk of cancer development. It's important to note that not all cancers in adults are hereditary, and having a gene mutation does not guarantee the development of cancer.

What types of cancer are hereditary?

Approximately 10% of all adult cancer patients have a hereditary predisposition to cancer due to gene mutations. Certain types of cancers are more likely to be hereditary than other types of cancers. A few examples include:

My mother had cancer, what does this mean for me?

Having a family member with cancer can increase your chances of having cancer and your future children’s chances of having cancer.

The most important information to assess your risk of developing cancer is information on your family's cancer history. What type of cancer did your family member have? How many family members have had cancer? Has anyone had genetic testing?

Genetic testing plays a crucial role in identifying hereditary cancer conditions in adults. Through genetic testing, individuals with a strong family history of cancer or known hereditary cancer conditions can ascertain their own genetic predispositions to cancer. If you have concerns or questions about your personal or family history of cancer, it is recommended you speak with a genetic counselor.

It is important to note that most adult cancers occur by chance and are influenced by a variety of environmental factors, such as tobacco use, exposure to certain chemicals, radiation, unhealthy lifestyle choices, and aging. Therefore, while genetic testing is a valuable tool in assessing the risk of hereditary cancers, but it cannot explain all family history of cancers.

Can I test my embryo for cancer?

While it is not possible to test an embryo for cancer, it is possible to screen an embryo for genes related to hereditary cancer and therefore an increased predisposition to cancer.

If your offspring is at increased risk of inheriting a hereditary cancer condition, embryo screening is available. Through embryo screening, Orchid can help you select embryos that did not inherit the hereditary cause for cancer seen in your family.

Regardless of your family history, there is a possibility for anyone to have a child with a hereditary cancer condition. Some hereditary cancers occur randomly in an individual, known as "de novo" cases. These individuals did not inherit the condition from a parent; it happened by chance in an embryo.. Genetic testing for a parent would not reduce the risk for these conditions. For instance, at least 7% of individuals with Familial Adenomatous Polyposis had the condition occur spontaneously. Over 20% of individuals with Von-Hippel-Lindau, and more than 10% of individuals with PTEN-related disorders also had the hereditary cancer conditions develop by chance in the embryo.

Orchid's embryo screening for hereditary cancers identifies embryos that have genetic changes known to increase predisposition to cancer, whether they are inherited or non-inherited (de novo). Some of the genes we screen for are:

  • Breast: Hereditary Breast and Ovarian Cancer (BRCA1, BRCA2), CDH1, PALB2, PTEN, TP52
  • Ovarian: Hereditary Breast and Ovarian Cancer (BRCA1, BRCA2)
  • Colorectal: Lynch Syndrome (MLH1, MSH2, MSH6, EPCAM*, PMS2*), Familial Adenomatus Polyposis (APC)
  • Gastric: CDH1
  • Melanoma: CDK4, CDKN2A
  • Endocrine: Multiple Endocrine Neoplasia Type 1 (MEN1), Multiple Endocrine Neoplasia Type 2 (RET)
  • Renal cell carcinoma: Von-Hippel-LIndau (VHL)

Can Genetic Testing Eliminate Cancer?

No. While genetic testing is a powerful tool, it is essential to note that not all cases of cancer can be eliminated through genetic testing alone. Cancers typically occur sporadically, without an identifiable genetic cause.

However, only through Orchid’s embryo screening can you reduce risk of several common hereditary cancer conditions that can cause cancer.

References

Mester, J., & Eng, C. (2012). Estimate of de novo mutation frequency in probands with PTEN hamartoma tumor syndrome. Genetics in medicine : official journal of the American College of Medical Genetics, 14(9), 819–822. https://doi.org/10.1038/gim.2012.51

Aretz, S., Uhlhaas, S., Caspari, R., Mangold, E., Pagenstecher, C., Propping, P., & Friedl, W. (2004). Frequency and parental origin of de novo APC mutations in familial adenomatous polyposis. European journal of human genetics : EJHG, 12(1), 52–58. https://doi.org/10.1038/sj.ejhg.5201088

Tsaousis, G. N., Papadopoulou, E., Apessos, A., Agiannitopoulos, K., Pepe, G., Kampouri, S., Diamantopoulos, N., Floros, T., Iosifidou, R., Katopodi, O., Koumarianou, A., Markopoulos, C., Papazisis, K., Venizelos, V., Xanthakis, I., Xepapadakis, G., Banu, E., Eniu, D. T., Negru, S., Stanculeanu, D. L., … Nasioulas, G. (2019). Analysis of hereditary cancer syndromes by using a panel of genes: novel and multiple pathogenic mutations. BMC cancer, 19(1), 535. https://doi.org/10.1186/s12885-019-5756-4

Wu, P., Zhang, N., Wang, X., Ning, X., Li, T., Bu, D., & Gong, K. (2012). Family history of von Hippel-Lindau disease was uncommon in Chinese patients: suggesting the higher frequency of de novo mutations in VHL gene in these patients. Journal of human genetics, 57(4), 238–243. https://doi.org/10.1038/jhg.2012.10

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