Dying cancer cells release a specific ketone that acts as a beacon to help the immune system finish the job.
April 25, 2026
Original Paper
Hypofractionated Radiotherapy Potentiates Rectal Cancer Immunotherapy by Eliciting Tumor-Derived β-Hydroxybutyrate to Promote Systemic Generation of M1-Like Macrophages
SSRN · 6642387
The Takeaway
Radiation therapy is known to kill tumors directly, but it also triggers a secondary immune response that was not fully understood. Scientists discovered that irradiated cancer cells produce a metabolite called beta-hydroxybutyrate. This ketone reprogrammes immune cells known as macrophages to become more aggressive in attacking the remaining tumor. It effectively turns a metabolic waste product into a signal that amplifies the power of immunotherapy. This finding could lead to new treatments where doctors combine radiation with specific diets or supplements to maximize this natural cancer-killing signal. The tumor death cry is what actually saves the patient.
From the abstract
Hypofractionated radiotherapy (HFRT) has emerged as a potent orchestrator of the tumor immune microenvironment (TIME). However, the key metabolic trajectories and intercellular metabolic communication triggered by HFRT that dictate immune outcomes in microsatellite stable (MSS) colorectal cancer (CRC) remain unclear. Here, we demonstrate that HFRT‑exposed CRC cells upregulate the ketogenic enzyme HMGCS2, leading to accumulation of β‑HB in the TIME. This tumor‑derived β‑HB predominantly acts on m