Structural proteins hold together large DNA strands to form chromosomes. In 1960, a researcher named Peter Nowell discovered the Philadelphia chromosome—the first recurrent genetic alteration associated with a specific human cancer.
Since then, scientists have taken tissues from the body, sliced them thinly, stained them, and then looked at the stained chromosome preparations to identify cancer-related mutations and determine whether to start radiation or chemotherapy. Chemotherapy works by killing cancer cells—sometimes, indiscriminately—which is why it can damage organs outside of the cancer site.
The evolution from broad-based therapy to targeted therapy
Today, we can learn so much more about different cancers by studying the genetics of the cancer cells. Through genomics—the study of all of a person’s genes (the genome), including the interactions of those genes with each other and with the person’s environment—physicians can make more-informed and potentially more-effective treatment decisions based on a deeper understanding of what’s really going on with the patient.
After completing the Human Genome Project (HGP), we finally understood that 30,000 genes exist in the human genome, which can be cataloged and documented, and that specific mutations within those genes can be identified. In turn, physicians can use genomic testing technologies to analyze a person’s tumor DNA in its entirety to understand which genes are mutated. By ascertaining the deep genetic changes caused by cancer and the proteins formed by those genetic mutations, researchers can develop new drugs that precisely target those proteins to prevent them from further impacting the cells. Called targeted therapies, these drugs are only interjected at that point in the cell cycle and at that cell biology, sparing the patient from chemotherapy-related side effects such as hair loss and mouth sores.
For example, physicians could before only treat chronic myelogenous leukemia (CML) through a blood and marrow transplant. Considering the rarity of these donors and the age of patients with CML, only about 35% of people with CML were eligible for a transplant. In effect, most people with CML died prematurely—at an average of about three years postdiagnosis. However, with the targeted drug imatinib, people with CML are living high-quality lives with the disease for decades, just by taking a couple of pills daily.
Precision medicine and the future of cancer care
Precision medicine is the ability to select a targeted therapy for a specific patient based on their cancer cells’ genomic/proteomic information. Just how effective is precision medicine? It has helped cancer-related deaths drop by the greatest margin ever over the previous two years.1
Learn more about precision medicine: Next-generation diagnostics and treatments.
The declining cost of genomic testing and proliferation of genomics testing laboratories
The cost of sequencing the entire human genome is rapidly decreasing. Originally, sequencing a human genome in 2001 cost $100 million; now, it’s only around $1,000—removing many barriers to performing the process. What’s more, through 2022, we expect that specialists will be developing substantially more sequencing technologies to help physicians make better decisions throughout the cancer journey.
Through molecular diagnostics, we now know that 100 patients with the seemingly same cancer under a microscope may actually represent many different cancer subtypes. As new information emerges daily on how we can use genomic data to precisely treat patients, physicians can turn to a molecular tumor board, which brings together cancer experts to discuss treatment plans based on a patient’s molecular profile, to interpret the results.
For patients who need more than the standard of care, physicians who can utilize the highly complex information to identify new clinical trials can powerfully turn a previously untreatable cancer into one that profoundly responds to a new therapeutic.
Keys to working effectively with genomic information
How we think about cancer has evolved dramatically—it’s no longer "one disease" defined by its site of origin. Precision medicine represents a quantum leap in how we use a patient’s own tumor-specific information to plan more-effective and less-toxic treatments. By effectively applying the technologies, physicians can more quickly and efficiently deliver more-effective treatments, enhance care, identify clinical trials, lengthen survival rates, and improve quality of life for patients with all types of cancer.
Last updated Aug 2, 2021
This post was authored by AccessHope and medically reviewed by Dr. Howard ‘Jack’ West.