Smoking linked to chemo resistance pathway in lung cancer

A cancer-immunology preprint posted on August 7, 2026, outlines a proposed molecular reason lung cancers exposed to chronic cigarette smoke may respond less effectively to chemotherapy. The authors describe an epigenetic chain in which smoke exposure is associated with increased EZH2 activity, lower levels of RIPK3, and weaker ferroptosis, a regulated form of cell death they connect to chemotherapy response.

The study was shared on bioRxiv and has not been validated through peer review. As a preprint, the findings should be treated as preliminary until independent groups confirm the results and the work is assessed through formal publication.

Preprint model centers on EZH2, RIPK3, and ferroptosis At the core of the preprint is the At the core of the preprint is the claim that cigarette-smoke exposure increases EZH2, which in turn suppresses RIPK3. In the authors’ model, reduced RIPK3 weakens ferroptosis and contributes to treatment resistance by limiting chemotherapy-induced tumor-cell killing. The biology described is framed as epigenetic regulation, meaning shifts in gene activity that do not change the underlying DNA sequence. The preprint highlights EZH2 as a histone methyltransferase that operates within the Polycomb repressive complex and can switch genes off through chromatin modification. RIPK3, short for receptor-interacting protein kinase 3, is widely known for its role in programmed cell-death signaling. In this work, it is positioned as an enabling factor for ferroptosis, an iron-dependent cell-death pathway that the authors say can be activated by some chemotherapies.

By placing RIPK3 as a gatekeeper of ferroptosis, the authors argue that epigenetic silencing of RIPK3 provides a route for tumor cells to evade chemotherapy-driven killing. They present this as separate from smoking’s established role in cancer development, proposing that smoke exposure may also alter how tumor cells die once treatment begins. Asia Pacific relevance and potential therapy strategy implications The preprint situates its potential importance in Asia Pacific, where tobacco use remains a major public-health and economic issue. It also points to demographic and disease-pressure context in the region, citing fast-aging populations and rising cancer incidence in several markets, while noting that lung cancer remains a leading cause of cancer mortality.

Clinicians have long observed that smoking history can correlate with poorer outcomes even as treatment options expand, according to the preprint’s framing. The authors argue that, if supported, the EZH2–RIPK3 pathway could offer a specific molecular explanation for those patterns.

For pharmaceutical and biotech stakeholders, the preprint says the findings could support testing epigenetic regulators such as EZH2 alongside existing chemotherapies. It also flags potential downstream effects on clinical-trial design and companion-diagnostic approaches, while emphasizing that these implications are contingent on validation.

What remains uncertain before peer review

The preprint identifies reproducibility as the key open question, including whether the proposed mechanism holds across additional lung-cancer models and human tumor datasets. The authors describe the chain as falsifiable—EZH2-driven suppression of RIPK3, reduced ferroptosis, and increased chemoresistance—setting out a framework other groups can test.

They set a timeline marker of 2026-12-31 for signs of confirmation through peer-reviewed publication or conference data. Outcomes to watch, according to the preprint, include evidence that the EZH2–RIPK3 axis works as a treatment-response marker, or findings that the effect is model-specific, non-causal, or not predictive in patient samples.