Blood Test Tracks Small Cell Lung Cancer Burden

Patients whose tumors are hard to re-biopsy may one day have a simpler way to track their disease.

Updated on Nov. 2, 2026 in Cancer

Clear glass vials of pale amber fluid sit in a wooden rack on a bright white laboratory bench, with a blurred steel instrument behind them. — Northwestern Medicine scientists showed a blood test using about 1 milliliter of blood can track small cell lung cancer burden, which accounts for roughly 15 percent of lung cancer cases. AI Illustration. Upload story photo >

Northwestern Medicine scientists demonstrated a blood-based technique that measures small cell lung cancer burden and molecular features. The study, published in the Journal of Clinical Investigation, used a method that needs only about 1 milliliter of blood, offering a possible alternative for patients whose tumors are hard to re-sample.

Why it matters

Small cell lung cancer accounts for roughly 15 percent of lung cancer cases, and repeat tumor biopsies are often impractical in patients with recurrent disease. A blood-based approach that reflects tumor activity could make it easier to track the disease over time without invasive procedures.

This peer-reviewed study analyzed 441 plasma samples from patients with small cell lung cancer, patients with other cancers, and healthy controls. The blood-based score correlated strongly with cancer burden shown on tumor imaging, but the study does not yet show clinical benefit in routine care.

The players

Northwestern Medicine

A academic medical system whose researchers led the study on blood-based detection of small cell lung cancer.

Hebrew University of Jerusalem

An Israeli research university whose scientists developed the cfChIP-seq technique used in the study.

Nir Friedman

A researcher at the Hebrew University of Jerusalem whose group pioneered the cfChIP-seq method.

The details

The technique, called cell-free chromatin immunoprecipitation sequencing (cfChIP-seq), examines DNA fragments and associated proteins that dying cells shed into the bloodstream. It analyzes active chromatin marks to determine which genes are switched on within tumor cells, allowing researchers to read tumor activity from a blood sample. The method was pioneered by Nir Friedman's research group at the Hebrew University of Jerusalem.

Study published in the Journal of Clinical Investigation, volume 136, in 2026.

Health Landscape

Small cell lung cancer has long been difficult to monitor because tumor tissue is hard to obtain repeatedly, which is why blood-based approaches have drawn research interest. This work moves an epigenetic blood test from the developers' laboratory toward possible clinical monitoring, though it remains at the research stage.

If you have lung cancer, ask your oncologist whether blood-based monitoring tests are an option in your care, since this research suggests they may someday reduce the need for repeat biopsies. This is early research, so any change to your monitoring plan should be a conversation with your doctor.

The takeaway

Blood-based tests that read tumor activity could eventually offer a less invasive way to follow small cell lung cancer over time. Patients with recurrent disease should discuss current monitoring options with their oncology team.