Towards Precision Medicine: Promises and Hurdles

Hyerim Kim

Originally published April 13, 2015

 Photo by: Jadiel Wasson

Photo by: Jadiel Wasson

If you’ve ever seen an ad on the internet that seemed as if it was intentionally catered to your interests, you’ve probably been subject to customization in marketing. While mass customization has become commonplace in fields such as marketing and manufacturing, its scope is extending further than just business. Advances in genetics are allowing doctors to start customizing medical treatments for individuals through a new field being called ‘Precision medicine.’

Before precision medicine, diagnosis and treatment of disease was determined by categorization without consideration of individual diversity. These procedures, albeit leading to a huge improvement compared to non-scientific treatment, have brought concerns about diagnostic accuracy and side effects of prescribed medicine.

Some of these concerns can be resolved by studies on the variation between the genes of different people. Scientists have launched international projects in order to illustrate the common patterns of human genetic variation. These ongoing efforts have helped in understanding why a certain population of people would be susceptible to a particular disease and what their responses would be to certain types of drugs.

A medical movement applying individual genetic data into medical practice is considered as a milestone in the journey toward precision medicine. The movement is gaining momentum, with the President’s 2016 Budget allocating it a $215 million investment. In particular, the system is expected to reap enormous benefits in cancer treatment.

Hence, we can now ask ourselves: What’s the success story for precision medicine we’re looking for, and what are current challenges faced by this medical movement?

Back in the 60s, chronic myeloid leukemia (CML) was a devastating disease and the average lifespan of patients was 3-7 years after diagnosis. However, a new genetic technique in 1970 enabled scientists to identify what caused the deadly disease, an abnormal molecule called Bcr-Abl. The elucidation of this abnormal molecule promoted the development of a new target therapy, “Gleevec” for CML patients. Since nearly all CML patients carry the fusion molecule, a therapeutic outcome was outstanding with higher efficacy and lower side effects compared to conventional chemotherapy.

The success of Gleevec brought to the field a concept of targeted therapy in cancer treatment, resulting in the development of many similar therapies. A wider breakthrough in targeted therapy, however, could not be accomplished without further technological innovation.

As technologies did develop, they were unfortunately too costly. However, newer sequencing platforms have led to the rapid reduction in DNA sequencing costs, and in the near future, $100 genome sequencing will be open to most people. As such, one can imagine genomic mutation profiling becoming routine in determining the best therapeutic regimens for individual cancer patients.   

Despite the mapping of a personal genome being expensive, the extraction of biological information from complex human genomes is a major obstacle to the start a precision medicine era.

To illustrate, the detailed biological functions of protein-coding genes (1 % of human genome) still needs to be explored, although the ENCODE Project launched to identify all functional elements of genome after the completion of the Human Genome Project has brought about substantial understanding about the genome. In addition, most genomic regions outside of what codes for proteins (99 % of human genome), such as promoters, enhancers, and insulator regions that regulate gene expression, remain to be elucidated. In particular, intergenic regions considered as “junk” DNA before are now thought to play regulatory roles in gene expression yet most of them remain uncategorized..

In other words, current genomic data is incomplete. In addition, there are no standard informatic programs to analyze raw sequencing data, and data storage and sharing are practical issues to be discussed. In order to overcome these limitations, international collaborations for breakthrough efforts are necessary.

In the case of cancer research, The Cancer Genome Atlas in the US, the Cancer Genome Project in the UK, and the International Cancer Genome Consortium have been launched to aim for a deeper understanding of individual cancer patients by managing and sharing the data from these projects. Such combined efforts to elucidate the human genome, standardize data processing, and generate publicly available datasets will pave the way for precision medicine.

Precision medicine is not a void dream. Along with technological innovation in genome research, individual diseases will be minutely categorized depending on an individual’s genetic makeup, and treatments will be carefully chosen based off of that information. In addition, patients will be able to access their own genomes so that they are able to play an active role in prevention of predisposed disease and treatment. Moreover, the pharmaceutical industry will have to restructure itself toward a more patient-oriented outlook. In terms of medical costs, we can save money from unnecessary examination to identify the cause of disease. As such, precision medicine is expected not only to realize optimal medical services to patients but also to transform medicinal industry in future. This realization, nevertheless, cannot be done by only an institute or a country. Collaborative research across the world to clarify undermined and undiscovered genomic data is essential.

Edited by: Anzar Abbas