By Anna C. Greene, PhD, NETRF Chief Scientific Officer
Why do some neuroendocrine tumors grow slowly for years, while others progress more quickly? Researchers have often looked to changes in DNA for answers. But many well-differentiated neuroendocrine tumors (NETs) have a relatively low mutational burden, and researchers have identified relatively few recurrent cancer-driving mutations compared with many other solid tumors.
This has led scientists to investigate another layer of tumor biology: epigenetics.
A recently published review, “Neuroendocrine tumours through an epigenetic lens: Emerging insights for diagnosis and treatment,” summarizes what researchers currently know about epigenetic changes in NETs and how these discoveries could eventually improve diagnosis, prognosis, and treatment.
What is epigenetics?
DNA contains the instructions cells use to function, but cells do not use every instruction at the same time. Epigenetic mechanisms help control which genes are active, which are quiet, and how strongly they are expressed.
These mechanisms do not usually change the DNA sequence itself. Instead, they act more like switches or dimmers that influence how genetic instructions are read.
In cancer, these controls can become disrupted. Genes that normally limit cell growth may be turned off, while programs that support tumor growth or spread may become more active.
The review examines several forms of epigenetic regulation, including:
- DNA methylation, which can influence gene activity and can reduce gene expression when it occurs in certain regulatory regions.
- Histone modification and chromatin remodeling, which affect how tightly DNA is packaged.
- Non-coding RNAs, which help regulate genes and cellular pathways.
Epigenetics and NETs
NETs can contain important genetic alterations. For example, some pancreatic neuroendocrine tumors have changes in MEN1, DAXX, ATRX, or genes involved in the mechanistic target of rapamycin (mTOR) signaling pathway.
However, researchers have not found a single common genetic driver that explains most NETs. Small-intestinal neuroendocrine tumors (SI-NETs), in particular, generally have relatively few recurring mutations.
This does not mean these tumors lack meaningful molecular changes. Some of the most important differences may involve how genes are regulated rather than changes to the genes themselves.
Studying epigenetic patterns may help researchers better understand where NETs originate, why tumors from different organs behave differently, and how their biology changes as they grow or spread.
Potential clues for diagnosis and prognosis
Epigenetic patterns can retain information about the type of cell from which a tumor developed. Researchers are investigating whether these molecular “fingerprints” could help classify NETs more accurately or identify the likely site of origin when the primary tumor is difficult to locate.
These patterns may also help divide tumors into biologically meaningful groups. Studies of pancreatic neuroendocrine tumors, for example, have identified DNA-methylation patterns associated with putative cells of origin, genetic alterations, and clinical behavior.
In the future, epigenetic biomarkers might help physicians estimate whether a tumor is more likely to remain slow-growing, recur, or spread. They could also help identify which treatment approach is best suited to an individual tumor.
Most of these applications remain under investigation. Larger studies will be needed before epigenetic biomarkers can become part of routine care.
Could epigenetic changes be treated?
One promising feature of epigenetic changes is that they may be reversible.
Researchers have developed drugs that affect DNA methylation, histone modification, and other epigenetic processes. Some of these therapies are already used to treat certain blood cancers.
In laboratory models of NETs, epigenetic approaches have slowed tumor-cell growth, promoted cancer-cell death, or caused cells to become more differentiated. Researchers are also exploring whether these treatments could make NET cells more responsive to other therapies.
However, promising laboratory findings have not yet consistently translated into meaningful benefits for people with NETs. Future progress will likely require more selective drugs, biomarkers that identify the tumors most likely to respond, and carefully designed treatment combinations.
Why sustained research funding is necessary
Scientific reviews do more than summarize previous discoveries. They identify gaps in knowledge and help researchers determine which questions should be addressed next.
The review acknowledges support from the Neuroendocrine Tumor Research Foundation for coauthor Benjamin Chevalier. This recognition reflects the role sustained research funding plays in building the evidence needed to move promising ideas toward clinical care.
At NETRF, we support research into the fundamental biology of neuroendocrine cancer because understanding how these tumors begin, grow, and resist treatment is essential to developing better therapies. Epigenetics is an important part of that effort.
Looking ahead
This review does not establish a new standard of care. Instead, it provides a roadmap for future research.
Next steps include studying larger groups of tumor samples, validating potential biomarkers, improving laboratory models, and testing epigenetic therapies in carefully selected patient populations.
By looking beyond changes in the DNA sequence and examining how NET cells control their genes, researchers are uncovering another important layer of neuroendocrine cancer biology. Each new insight brings us closer to more precise diagnoses, better-informed treatment decisions, and more effective therapies.