Israeli and American scientists have developed a blood-based method that could make the monitoring and future treatment of small-cell lung cancer more precise. The technology shows not only how large the tumor is, but also which genes are active in cancer cells.
The study was led by Prof. Nir Friedman and Dr. Gavriel Fialkov of the Hebrew University and Hadassah Medical School, together with Dr. Nobuyuki Takahashi and Dr. Anish Thomas of the U.S. National Cancer Institute. The results were published in Journal of Clinical Investigation.
How the method works
The team analyzed 441 blood plasma samples from patients with small-cell lung cancer, other types of cancer and healthy individuals. Only about 1 milliliter of plasma was needed for the analysis.
The method, known as cfChIP-seq, analyzes DNA fragments bound to proteins called histones. Chemical markers on the histones show which genes were active in the cells that released these fragments into the bloodstream.
This distinguishes the technology from many existing liquid biopsies, which primarily look for mutations in tumor DNA. In small-cell cancer, important information is also contained in the way cancer cells use their genetic code.
Monitoring the tumor and its subtypes
The scientists developed a molecular index whose value was linked to the tumor burden determined through imaging. Average values decreased after treatment, corresponding to a reduction in tumor burden. Higher values were also associated with shorter survival.
The blood analysis also revealed molecular subtypes of small-cell lung cancer. They differ in gene activity and may explain why individual patients respond differently to the same treatment.
“A blood test that simultaneously shows the tumor burden and molecular identity could in the future help doctors monitor treatment response, detect changes as resistance develops and understand which patients might benefit from new therapies,” said Dr. Anish Thomas.
The method is still experimental
Small-cell lung cancer accounts for approximately 15% of all lung cancer cases. The disease usually develops rapidly and is often diagnosed at an advanced stage, when obtaining a new tissue sample can be difficult.
The researchers emphasize that larger prospective studies are needed before the technology can be incorporated into routine medical practice. It is not intended to replace tissue biopsy when sufficient material can be safely obtained from it. The next step is to test the method through repeated blood sampling during treatment to determine whether it can predict the response to therapy and the emergence of resistance.
Sources: israel.fm