MYC: The Cancer Oncogene’s Dual Role in Tumor Growth and Immune Evasion

For decades, the MYC oncogene has been recognized as a key driver of cancer, fueling rapid cell proliferation. Still, recent research reveals a more nuanced understanding of MYC’s function, demonstrating its critical role in helping cancer cells evade the immune system. This discovery shifts the paradigm of MYC as solely a growth promoter and opens new avenues for targeted cancer therapies.

The Traditional Understanding of MYC

The MYC family of oncogenes – consisting of c-Myc, N-Myc and L-Myc – are often deregulated in over 50% of human cancers, correlating with poor prognosis and reduced patient survival. ¹ MYC functions as a “super-transcription factor,” regulating the expression of genes involved in cell cycle progression, metabolism, ribosome biogenesis, and protein translation. ¹ This broad control over cellular processes contributes to the uncontrolled growth characteristic of cancer.

Beyond Growth: MYC’s Role in RNA Quality Control and Immune Evasion

Recent studies have uncovered an atypical function of MYC: its involvement in RNA quality control. When cancer cells exhibit abnormally high gene expression, DNA becomes unstable, leading to the formation of RNA-DNA hybrids known as R-loops. ³ MYC binds to newly synthesized RNA, forming dense molecular condensates within the nucleus. These condensates don’t promote gene expression; instead, they act as a platform for eliminating these aberrant nucleic acid structures that could trigger an immune response.

R-loops and the Immune System

R-loops, if left unchecked, are recognized by cells as abnormal structures, initiating immune sensing pathways. MYC resolves this by recruiting RNA-degrading enzymes to these RNA-DNA hybrids, effectively removing them before the immune system can detect them. ³ This process effectively silences the immune alarm, allowing cancer cells to proliferate undetected.

Disrupting Immune Evasion: A New Therapeutic Strategy

By eliminating R-loops, MYC prevents activation of the cGAS-STING pathway, a key immune signaling cascade that alerts immune cells to the presence of abnormal DNA. ³ Researchers have demonstrated this by creating mutant MYC proteins unable to bind RNA. Tumors expressing these mutant proteins were still capable of proliferation, but were more susceptible to immune system clearance. ³ This highlights MYC’s distinct functional areas: growth promotion and immune evasion.

From “Undruggable” to “Precision Strike”

MYC has long been considered an “undruggable” target due to its widespread physiological functions and the potential for severe side effects with complete inhibition. ¹ However, this new understanding of MYC’s role in RNA processing offers a more targeted approach. Instead of completely blocking MYC, researchers are exploring ways to specifically interfere with its RNA-binding function, thereby reactivating the immune system’s anti-cancer surveillance mechanisms while minimizing off-target effects.

Looking Ahead

The discovery that MYC acts as both a driver of cell proliferation and a protector from immune attack represents a significant advancement in cancer research. ¹ By controlling RNA quality and eliminating R-loops, MYC allows cancer cells to rapidly proliferate while remaining “invisible” to the immune system. Future research focused on disrupting the MYC-RNA interaction holds promise for developing more effective and less toxic cancer therapies.