Dr. Francis Collins analyzing an autoradiogram displaying the results of a Sanger DNA sequencing experiment, such as that used in the early years of the Human Genome Project. (NHGRI Photo Archive)
The National Human Genome Research Institute of the National Institute of Health (NIH) defines personalized medicine (also known as precision medicine) as “an emerging practice of medicine that uses an individual’s genetic profile to guide decisions made in regard to the prevention, diagnosis, and treatment of disease.”
Personalized medicine came to fruition 1990 when the Human Genome Project, funded by the United States Department of Energy and the NIH, brought together scientists and researchers from around the world in an attempt to map the human genome. By 2003, the Human Genome Sequencing Consortium announced that it had successfully mapped 92 percent of the human genome. Years later in 2022, the Telomere-to-Telomere (T2T) Consortium filled in the remaining gaps, producing the first complete human genome sequence.
As technologies have continued to emerge throughout the years, the potential for how personalized medicine can impact how diseases are treated has, and will, continue to increase.
What is Personalized Medicine?
In today’s health care climate, treatment decisions often derive from population studies, meaning disease treatment and testing protocols are based on a one-size-fits-most model. As a result, there is an opportunity in health care to deliver personalized treatment and prevention planning that is tailored for unique patient needs. Personalized or precision medicine can utilize new and novel ways of testing and gathering personal data to individualize diagnosis and treatment for each patient instead of the average population.
The heart of personalized medicine lies in advanced technology and the library of patient data. This is used to develop targeted therapy and intervention that could potentially minimize adverse effects of the patient’s treatment protocol. Instead of relying only on symptoms and average population studies, the technology today allows for the use of genetic and genomic sequencing to formulate individual treatment plans based on a person’s genetic code.
How Can it Help?
Genetic mutations that cause disease are not new to students or practitioners of laboratory medicine. For example, we know that sickle cell disease is caused by a mutation at a genetic level, resulting in the amino acid valine being substituted for glutamic acid at the sixth position of the beta globin chain of the hemoglobin molecule. Although we have this information, it has not resulted in any advanced treatment or therapeutic protocols. It is more descriptive rather than prescriptive.
In contrast, more recently we learned that the discovery of a genetic mutation of the BRCA1 and BRCA2 genes result in higher rates of breast and ovarian cancer in women and higher rates of prostate and breast cancer in men. Normal BRCA genes function as DNA, repairing genes that can suppress the oncogenic transformation of cell development and helping to suppress the development of cancer cells. These BRCA mutations can be tested when there is a family history or a hereditary component of these types of cancers. Measures can be taken to help mitigate the development of these cancers with consideration of prophylactic therapies. Genetic factors have also been identified in hereditary heart conditions where physicians can formulate early treatment and prevention plans that may result in decreased morbidity.
Testing is currently available for numerous genetic markers with molecular platforms that can perform Next Generation Sequencing or NGS. NGS can sequence hundreds to thousands of genes and gene mutations that can aid in the diagnosis and treatment of disease. For example, Henry Schein Medical partners with Vela Diagnostics to provide health care professionals with NGS solutions specifically for oncology and virology clinical and research use.
The BRCA 1 and 2 mutation mentioned earlier only scratches the surface of what is available. There are numerous methods for detecting gene mutations for several types of cancer, leukemia, viruses, fungi, parasites, etc. As more mutations are identified, the list will continue to grow.
The Field of Pharmacogenomics
Another byproduct of human genome mapping is in the field of pharmacogenomics. This takes into consideration the role of genes in a patient’s response to medications used in treatment. Researchers are studying how variations in genetics affect how the body responds to certain medications. This can help determine dosage levels and drug efficacy in an effort to reduce drug toxicity. The thought of the right medicine, at the right time, for the right patient, is something to look forward to.
The Challenges of Personalized Medicine
The potential of precision medicine using genetic sequencing is overwhelming. With that in mind, it is important to understand the challenges as well. Right now, the availability of this testing is not routine and may not be readily accessible. The testing protocols are also highly complex and although they have decreased in cost, they are more expensive than what is considered to be routine laboratory testing today.
Additionally, many of the marker protocols are research use only (RUO) and require expertise that parallels that of developing a laboratory developed test (LDT). This requires the complex and time-consuming protocols for validation of the method and results. The other variable that should not be ignored is the cost of the genetic test. These costs can range from a few hundred dollars per marker to several thousand dollars depending on the number of markers evaluated. It is also not concrete if insurance will cover the cost. Patients and physicians should always verify coverage so there are no surprises.
Finally, results and confidentiality should be considered. For large populations and the variability within those populations, massive amounts of genetic profiles should be collected from these diverse populations in order to get the best results. The question is who and how will all this personal data be used and safeguarded? One can imagine the various scenarios that can take place should a genetic library be compromised with the possibility (no matter how remote) of people’s identities also being compromised at the same time.
Individuals undergoing these types of tests should also participate in genetic counseling. A positive result for a cancer mutation does not necessarily mean that the patient will develop cancer. It only can show a higher probability. Preventive treatment regimens can be extreme and should not be taken lightly. There are also economic considerations that should be addressed. With the disparities in access to good health care, it is important to ensure equitable access to this testing and targeted therapies.
Where Personalized Medicine is Headed
While there are challenges, the benefits and opportunities of personalized medicine using gene sequencing technology are continuing to be explored. With ongoing and increasing focus on preventive medicine, targeted therapies, and improving patient outcomes, the true value of what is to come by utilizing this innovative technology is exciting.
About the Author: Charles Starr is a member of Labcompare's Editorial Advisory Board. Starr graduated from Northeast Louisiana University in with a degree 
in Clinical Laboratory Science. For nearly 20 years, he held various roles ranging from an evening/night bench technologist to a hospital lab evening and night supervisor. In conjunction with his lab supervisory duties, Starr assumed a teaching role as a part-time instructor at Northeast Louisiana University where he taught clinical chemistry and toxicology. Later, he became program director of the Laboratory Internship Program at St. Francis Medical Center in Louisiana. Currently, Starr serves as the Senior Director of Sales for the Clinical Laboratory Services–West Area Sales Team at Henry Schein. In this role, he is responsible for driving company strategy for the sales of laboratory instrumentation, supplies, and consumable products in all laboratories, waived and non-waived, that provides testing at the point of care of the patient.