For decades, oncologists have grappled with a frustrating reality: some tumors simply refuse to die. Even when hit with the most aggressive doses of chemotherapy and radiation, certain cancer cells manage to recover, adapt and continue growing. A new study has finally shed light on why some cancers survive chemotherapy, revealing that a notorious protein acts as a biological “mechanic,” repairing the very damage these treatments are designed to inflict.
The research, published in the journal Genes & Development, focuses on MYC, a protein that is abnormally active in the vast majority of human cancers. While scientists have long known that MYC fuels tumor growth and metabolism, researchers at Oregon Health & Science University (OHSU) discovered that the protein performs a second, more insidious role: it physically intervenes to fix dangerous breaks in the cancer cell’s DNA.
This discovery transforms the understanding of treatment resistance. By actively repairing the genomic wreckage caused by chemotherapy, MYC allows tumor cells to endure conditions that would normally trigger cell death, leading to poorer patient outcomes and the eventual recurrence of the disease.
“Our work shows that MYC isn’t just helping cancer cells grow — it’s also helping them survive some of the very treatments designed to kill them,” said senior author Rosalie Sears, Ph.D., Krista L. Lake Chair in Cancer Research and co-director of the OHSU Brenden-Colson Center for Pancreatic Care.
The Hidden Mechanic of Tumor Survival
To understand the significance of this finding, It’s necessary to understand how most cancer therapies work. Chemotherapy and radiation are essentially “scorched earth” strategies; they function by overwhelming a cancer cell with so much DNA damage that the cell can no longer function or replicate, eventually forcing it to undergo apoptosis, or programmed cell death.
However, the OHSU team found that MYC provides a survival loophole. In a process the researchers describe as “non-canonical”—meaning it deviates from the protein’s known primary function—a modified version of MYC moves directly to the site of DNA damage. Once there, it acts as a scaffold, gathering the necessary repair proteins to stitch the DNA back together.
“What we have is a nontraditional, or non-canonical, role for MYC,” Sears explained. “Instead of controlling gene activity, it’s physically going to sites of DNA damage and helping bring in repair proteins.”
Gabriel Cohn, Ph.D., the study’s first author, who conducted the research at OHSU before moving to the University of Würzburg, noted that this mechanism is particularly critical for tumors under extreme stress. “Tumor cells in these cancers experience significant DNA damage and replication stress, yet they continue to survive and grow,” Cohn said. “Our work suggests that MYC helps these cells cope with that stress by actively promoting DNA repair.”
The Critical Link to Pancreatic Cancer
While MYC is active in many cancers, the implications are most stark for aggressive malignancies like pancreatic cancer. This disease is notorious for its low survival rates and its profound resistance to standard therapies. The OHSU team used tumor data and patient-derived pancreatic cancer cells to confirm that high levels of MYC activity correlate directly with increased DNA repair efficiency and worse clinical outcomes.
In these aggressive tumors, MYC helps the cancer tolerate a “perfect storm” of stress. This includes the internal stress of rapid, uncontrolled growth, the external stress of a poor blood supply (hypoxia), and the artificial stress of chemotherapy.
The researchers observed that cells with the active, modified form of MYC were significantly more likely to survive exposure to DNA-damaging treatments than those without it. This suggests that the protein creates a protective shield, allowing the tumor to “weather the storm” of chemotherapy and emerge intact.
Breaking the “Undruggable” Barrier
For years, MYC has been labeled “undruggable” by the scientific community. Because of its smooth structure and the way it interacts with other proteins, it has proven nearly impossible to design a drug that binds to it securely without also damaging healthy cells.
However, the discovery of MYC’s role in DNA repair provides a new, more precise target. Rather than trying to shut down every function of the protein—which would be toxic to the body—scientists believe they can specifically interfere with its ability to repair DNA. By blocking this “mechanic” function, they could potentially strip cancer cells of their defenses, making them vulnerable to existing chemotherapies once again.
“MYC is one of the two most critical oncogenes in all of human cancer,” Sears said. “If we can interfere with MYC’s role in DNA repair — without shutting down everything MYC does in healthy cells — we may be able to make cancer cells more vulnerable to treatment.”
This theoretical approach is already moving toward clinical application. OHSU is currently conducting a “window of opportunity” trial involving a first-in-class MYC inhibitor known as OMO-103. In this study, patients with advanced pancreatic cancer undergo biopsies both before and after receiving the drug to determine exactly how blocking MYC alters the behavior and survival of the tumor in a living patient.
| MYC Function | Traditional Role | Newly Discovered Role |
|---|---|---|
| Primary Action | Controls gene activity in the nucleus | Physically moves to DNA damage sites |
| Impact on Tumor | Drives growth and metabolism | Facilitates DNA repair and survival |
| Clinical Result | Tumor proliferation | Chemotherapy and radiation resistance |
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Patients should consult with their oncology team regarding treatment options and clinical trial eligibility.
The next phase of research will focus on the results of the OMO-103 trial, which will provide critical data on whether inhibiting MYC’s repair capabilities can successfully sensitize aggressive tumors to standard care. As the medical community awaits these results, the study provides a vital roadmap for overcoming treatment resistance in some of the world’s deadliest cancers.
Do you have questions about new cancer research or treatment resistance? Share your thoughts in the comments or share this article with others who may find it helpful.
Related reading
