A newly developed blood test has the potential to significantly improve cancer detection in patients presenting non-specific symptoms, such as fatigue, pain, or weight loss. This breakthrough comes from a comprehensive study conducted by researchers at the Karolinska Institutet and Danderyd Hospital, along with collaboration from Örebro University, KTH Royal Institute of Technology, and SciLifeLab at Uppsala University. The findings were published in the journal Nature Communications on December 29, 2025.
Patients often encounter challenges when seeking medical care for vague symptoms, as it can be difficult to determine if the underlying cause is cancer, another serious illness, or something benign. The researchers aimed to explore whether specific proteins in the blood could provide early indicators of cancer. To achieve this, they analyzed blood samples from nearly 700 patients referred to the Diagnostic Centre at Danderyd Hospital and Örebro University Hospital.
Utilizing proteomics—a technique for large-scale protein analysis—the study measured the levels of 1,463 different proteins in plasma samples collected prior to diagnostic investigations. The researchers successfully identified a unique combination of proteins, termed a “protein signature,” which correlates with a cancer diagnosis.
“The study shows the potential of large-scale proteomics for extracting clinically relevant information from small amounts of blood,” stated Mikael Åberg, an associate professor at Uppsala University and head of the SciLifeLab Affinity Proteomics unit, where the analyses were conducted.
The team also developed a model capable of distinguishing patients with cancer from those suffering from other conditions, such as inflammatory, autoimmune, or infectious diseases, with a high degree of accuracy. Charlotte Thålin, a senior physician at Danderyd Hospital and principal investigator for the study, remarked, “A particular strength of the study is that the control group consisted largely of patients with other serious conditions that can cause symptoms similar to cancer. This reflects the clinical reality, where patients with non-specific symptoms are often difficult to assess.”
While the researchers emphasize that this blood test should not replace traditional imaging diagnostics or biopsies, it could serve as a valuable tool for prioritizing which patients require further examination. Fredrika Wannberg, a resident at Danderyd Hospital and doctoral student at Karolinska Institutet, noted, “The method could help identify which patients should be prioritized for further diagnostics, for example with PET-CT, while avoiding unnecessary investigations in patients without cancer.”
Further research is necessary before implementing this method in clinical settings. The next phase will involve testing the approach in primary care environments, where the incidence of cancer is generally lower compared to specialized care.
The study received funding from various sources, including the Swedish Research Council, the Knut and Alice Wallenberg Foundation, and the Jochnick Foundation. The researchers declared no conflicts of interest.
The full study, titled “Plasma protein profiling predicts cancer in patients with non-specific symptoms,” has been made available online in Nature Communications and can be accessed through the DOI: 10.1038/s41467-025-67688-3.
