Melanoma rates are climbing worldwide, intensifying the urgency to find biomarkers that will help doctors optimize treatment. New research suggests that a simple blood test may detect a biomarker of survival in people with melanoma. The researchers counted tumor cells in blood samples from 101 people with melanomas that had spread and found that those with fewer tumor cells in their blood lived longer. When people had under two tumor cells per 7.5 mL of blood, they survived on average more than twice as long as those with two or more tumor cells per 7.5 mL of blood (7.2 vs 2.6 months). The researchers reported this finding in the Journal of Investigative Dermatology and recommend larger studies to confirm their work.