Genetic Screening: History and Recent Progress

  • Published: April 22, 2024
  • Updated: April 22, 2024

Just as cancer is not a single disease but a complex family of diseases, its triggers also vary. Ten to 20 percent of cancers are believed to be caused by genetic mutations, making genetic testing an important tool in cancer screening. DNA collected through a cheek swab or simple bloodwork can be tested for mutations that may show a family history of cancer, or mutations that increase an individual’s risk for cancer, including the BRCA1, BRCA2, and Lynch Syndrome genes.

First discovered in 1994 and 1995, BRCA1 and BRCA2 serve as the body’s tumor suppressor genes. Mutations in these genes prevent them from working properly, increasing the risk of breast or ovarian cancers.

Genes associated with Lynch Syndrome (MLH1, MSH2, MSH6, PMS2, and EPCAM) are involved in DNA replication. Data on Lynch Syndrome were first published in 1961, when Henry T. Lynch, MD, noted similarities among families whose members were diagnosed with related cancers. For example, an individual with Lynch Syndrome or HNPCC (hereditary non-polyposis colorectal cancer) faces a higher risk of colorectal, uterine (endometrial), and other cancers. This risk becomes evident before age 50, so early genetic testing allows people and their families to make informed medical decisions.

For those with a family history of cancer, there are many benefits to early genetic testing. Of 100 women with BRCA gene mutations, 50 will develop breast cancer before they are 70 years old; by contrast, only 7 of 100 women in the general population will do so. Equipped with knowledge of genetic mutations, high-risk individuals can take additional preventive measures, including more frequent screenings and surgeries, such as preventive prophylactic mastectomy. Genetic testing is also valuable to families, who can build detailed health histories to inform their health care decisions.

Individuals seeking genetic testing are encouraged to speak with a genetic counselor about their personal risks. However, while many health insurance plans cover testing for high-risk individuals, Medicare coverage does not include any genetic testing except for those with an existing cancer diagnosis.

Fortunately, there have been legislative efforts at the state and federal level to increase awareness of, and access to, genetic counseling. States including Pennsylvania have enacted innovative bills that remove out-of-pocket costs for breast cancer screening and genetic testing. California has passed CA SCR33, which designates May 3rd as Hereditary and Genetic Cancer Awareness Day. At the federal level, AACI has joined over 110 organizations to support the Reducing Hereditary Cancer Act of 2023 to provide Medicare coverage for germline mutation testing in hereditary cancer genes. Federal bills include H.R.7714, the Colorectal Cancer Early Detection Act, introduced in 2024 by Representative Yadira Caraveo (D-CO).