In a finding that challenges decades of assumptions about blood cancer, an international research team has shown for the first time that a specific subtype of diffuse large B cell lymphoma (DLBCL), which is the most common blood cancer in adults, is dramatically more lethal in women than in men.

A simple blood test can reveal the geographic relationships among healthy cells surrounding a cancerous tumor, researchers at Stanford Medicine and the Mayo Clinic have found. The test is the first noninvasive way to study what’s called the tumor microenvironment, which plays a critical role in determining how different patients—even those with similar tumors—fare after diagnosis and treatment.