Kidney cancer gene reveals an unexpected weakness and a new path for treatment

In a laboratory in Charleston, South Carolina, a team of cancer researchers has discovered something remarkable: a hidden weakness in one of the most aggressive forms of kidney cancer. The finding, published in the journal Cancer Research, could eventually lead to new treatments for patients who currently have few options.

The discovery centers on a gene called SETD2, which acts as a tumor suppressor — meaning it helps keep cells from growing out of control. In roughly 20 to 25 percent of kidney tumors, this gene is missing entirely. Patients whose cancers lack SETD2 tend to have more aggressive disease and poorer outcomes.

"The central question was why tumors experience loss of SETD2 in the first place," said Aguirre de Cubas, Ph.D., who led the research at the MUSC Hollings Cancer Center. "We don't fully understand what advantages its loss provides to tumor cells. Understanding that biology could reveal vulnerabilities that can be exploited therapeutically, which is important for patients with limited treatment options."

What de Cubas and his colleagues found was striking. Kidney cancer cells that had lost SETD2 had become heavily dependent on a protein called BCL-xL, which normally acts like a cellular bodyguard by preventing programmed cell death. Most healthy cells can survive without relying heavily on BCL-xL, but the SETD2-deficient cancer cells had become dangerously dependent on it.

When the researchers blocked BCL-xL, the results were dramatic: the SETD2-deficient cancer cells died rapidly, while kidney cancer cells that still had the SETD2 gene remained largely unaffected.

"It was an unexpected finding," de Cubas said. "What we uncovered was essentially an Achilles' heel. By losing SETD2, these tumors gain certain advantages that help them grow, but they also become highly dependent on BCL-xL for survival. That dependency creates a therapeutic opportunity."

The team traced the root of this vulnerability to the mitochondria — the structures inside cells that convert food into energy. They found that cells without SETD2 experienced mitochondrial stress that caused small amounts of DNA to leak out into the cell's interior.

"DNA is not supposed to be floating around in the cytoplasm," de Cubas explained. "When the cells detect DNA where it shouldn't be, they interpret it as a danger signal, often resembling a viral infection." This alarm triggers a molecular pathway called cGAS-STING, part of the body's innate immune defense system.

SETD2 alterations occur in approximately 5 percent of all solid cancers, but they are especially common in clear cell renal cell carcinoma, which makes up nearly three-quarters of all kidney cancers. Once this type of cancer spreads beyond the kidney, it becomes difficult to treat.

The research is still in early stages — it has only been tested in laboratory models so far. But by identifying exactly how SETD2 loss creates a dependence on BCL-xL, the team has laid groundwork for developing drugs that could exploit this vulnerability, potentially offering a new precision treatment for patients with this aggressive subset of kidney cancers.

For patients facing limited treatment options, the discovery represents a meaningful step forward — a hidden strength hidden within what has long been seen as a weakness.