Blood Test Measures Small Cell Lung Cancer Burden

Researchers demonstrated a liquid biopsy technique that reads cancer gene activity and burden from a small blood sample.

Updated on Nov. 2, 2026 in Cancer

Clear unlabeled test tubes of pale amber liquid in a row on a clean laboratory bench, with soft daylight and a blurred steel instrument behind. — Researchers at Northwestern Medicine showed a blood test can measure small cell lung cancer burden and gene activity, offering a less invasive alternative to repeat tumor biopsies. AI Illustration. Upload story photo >

Northwestern Medicine scientists showed that a liquid biopsy technique can measure small cell lung cancer burden and molecular characteristics from blood. The findings were published in the Journal of Clinical Investigation.

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 could offer a less invasive way to track the disease.

The study analyzed 441 plasma samples from small cell lung cancer patients, patients with other cancers, and healthy controls, using as little as 1 milliliter of blood, and the blood-based score correlated strongly with tumor burden on imaging. Small cell lung cancer accounts for about 15 percent of lung cancer cases, and the results have not yet been tested in larger prospective trials.

The players

Northwestern Medicine

A major academic medical system whose scientists led the study demonstrating the liquid biopsy technique for small cell lung cancer.

Nir Friedman

A researcher at the Hebrew University of Jerusalem whose group pioneered the cfChIP-seq technique used in the study.

The details

The technique, cell-free chromatin immunoprecipitation sequencing (cfChIP-seq), examines DNA fragments and associated proteins shed into the bloodstream by dying cells to identify which genes are active in tumor cells. It was pioneered by Nir Friedman's research group at the Hebrew University of Jerusalem and identified key gene-expression features of small cell lung cancer from a blood sample.

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

Health Landscape

The work extends the liquid biopsy research effort, which has largely focused on circulating tumor DNA, by reading active gene-expression signatures rather than only genetic mutations. Its focus on small cell lung cancer addresses a disease where tissue sampling is difficult and therapy monitoring has been limited.

For patients with recurrent small cell lung cancer, a future blood test could reduce the need for repeated tissue biopsies to track disease. Any clinical use remains years away pending larger studies.

The takeaway

Blood-based tests may eventually offer a practical way to monitor cancers that are hard to biopsy repeatedly. Patients should continue to rely on their oncology team for current monitoring and treatment decisions.