Public Release: 

Arteries better than veins for liquid biopsy

Arteries contain higher numbers of circulating tumor cells than veins in uveal melanoma patients, raising a concern for standard technique for detection of tumor cells in the blood

Thomas Jefferson University

(PHILADELPHIA) - As the field of liquid biopsies for tracking disease progression and therapeutic response heats up, many doctors are looking for ways to apply this approach to their patients. Currently, assays for circulating tumor cells (CTCs) - one type of liquid biopsy - have been approved for diagnostic purposes in metastatic breast, colorectal, or prostate cancer. In these diseases, the presence of CTCs in the peripheral blood is associated with decreased progression-free survival and decreased overall survival. The major challenge for this technology is that CTCs are not always found in the blood of patients with aggressive disease who would be expected to have high numbers. Now, researchers at Thomas Jefferson University investigating uveal melanoma, a type of melanoma that originates in the eye, have shown that the low numbers could simply be explained by where the blood is drawn - whether from a vein or an artery.

In breast cancer, a high number of CTCs (more than 5 cells in 7.5 ml of blood collected from the veins) indicates aggressive metastatic disease, or disease that has stopped responding to treatment. "If we can validate this approach for uveal melanoma, we hope to be able to catch cancer before it develops into metastatic disease," says Takami Sato, M.D., the K. Hasumi Professor of Medical Oncology at Thomas Jefferson University and lead investigator on the paper. "The work by Dr. Mizue Terai and others at Jefferson gives us hope that CTC might be useful for uveal melanoma patients as well. On the other hand, our research raised a concern that venous blood specimencs, which are tested as the standard practice for CTC measurement, might not be the best source for CTC detection." The results were published online in the journal EBioMedicine.

Circulating tumor cells are larger than other blood cells and have different chanracterisitics from normal blood cells. Therefore, CTCs can be detectable in the blood samples with modern technology. Most commonly, blood samples are obtained from a patient's vein, which has already passed through an intricate sieve of narrow capillaries throughout the body before draining to the veins. Indeed, when Mizue Terai, PhD and colleagues compared blood samples taken from uveal melanoma patients' veins compared to that collected from arteries, they saw a much higher number of circulating tumor cells in blood collected from the arteries than in the veins. In fact, all of the uveal melanoma patients with multiple liver metastasis had CTCs present in their arterial blood, while only 53 percent of blood sampled from the veins of those same patients had CTCs.

Although it is more technically difficult to collect blood from an artery than a vein, this and other research suggests that checking arterial blood may be a more accurate way of assessing circulating tumor number, and therefore metastatic disease.


This study was supported by the Wills Vision Research Center at Jefferson Innovation Grant, Mark Weinziel Research Fund, Bonnie Kroll Research Fund, and Eye Melanoma Research Fund at Thomas Jefferson University. The authors report no conflicts of interest.

Article reference: M. Terai et al., "Arterial Blood, Rather Than Venous Blood, is a Better Source for Circulating Melanoma Cells," EBioMedicine, doi:10.1016/j.ebiom.2015.09.019, 2015.

For more information, contact Edyta Zielinska, 215-955-5291,

About Jefferson -- Health is all we do. Our newly formed organization, Jefferson, encompasses Thomas Jefferson University and Jefferson Health, representing our academic and clinical entities. Together, the people of Jefferson, 19,000 strong, provide the highest-quality, compassionate clinical care for patients, educate the health professionals of tomorrow, and discover new treatments and therapies that will define the future of health care.

Jefferson Health comprises five hospitals, 13 outpatient and urgent care centers, as well as physician practices and everywhere we deliver care throughout the city and suburbs across Philadelphia, Montgomery and Bucks Counties in Pa., and Camden County in New Jersey. Together, these facilities serve more than 78,000 inpatients, 238,000 emergency patients and 1.7 million outpatient visits annually. Thomas Jefferson University Hospital is the largest freestanding academic medical center in Philadelphia. Abington Hospital is the largest community teaching hospital in Montgomery or Bucks counties. Other hospitals include Jefferson Hospital for Neuroscience in Center City Philadelphia; Methodist Hospital in South Philadelphia; and Abington-Lansdale Hospital in Hatfield Township.

Thomas Jefferson University enrolls more than 3,900 future physicians, scientists, nurses and healthcare professionals in the Sidney Kimmel Medical College (SKMC), Jefferson Colleges of Biomedical Sciences, Health Professions, Nursing, Pharmacy, Population Health and is home of the National Cancer Institute (NCI)-designated Sidney Kimmel Cancer Center.

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