Necroptosis in cancer therapy: bridging radiotherapy, tumor immunity, and treatment resistance

Necroptosis occupies an unresolved paradox in cancer biology: the same RIPK1–RIPK3–MLKL-driven, caspase-independent death program can either prime potent antitumor immunity or fuel the chronic inflammation that drives tumor growth, and the field has lacked a framework for predicting which outcome a given tumor will produce. This review addresses that gap by synthesizing evidence across more than a dozen tumor models into five variables that govern the balance, the acuity and context of induction, the specific downstream mediator engaged, host immune competence, tumor genetic background, and dependence on RIPK3 itself, and maps the existing literature against them in a dedicated comparative table. Radiotherapy emerges as a uniquely tractable setting for exploiting this duality: in several tumor models, irradiation activates RIPK1–RIPK3–MLKL or ZBP1–MLKL signaling that caspase-8 normally restrains, engaging cGAS–STING–type I interferon signaling, dendritic-cell cross-priming, and CD8⁺ T-cell responses, with efficiency shaped directly by radiation dose and fractionation; in other models, the same signaling instead drives IL-8-mediated tumor repopulation. We further show that pharmacologically restoring silenced RIPK3 or MLKL, a common strategy for re-sensitizing resistant tumors, is often insufficient on its own, since parallel resistance mechanisms such as compensatory ADAR1 upregulation can independently block the pathway even after successful epigenetic reversal. Clinical translation remains constrained by the absence of a validated necroptosis biomarker, though emerging circulating markers and trial data on the sequencing of checkpoint blockade relative to radiotherapy offer concrete starting points. By reframing necroptosis not as a generic form of cell death but as a mechanistic hub linking radiotherapy, immune sensing, and therapeutic resistance, this review provides a structured, actionable basis for the combination therapies needed to harness this pathway safely in the clinic.