Dr. Anil Vachani is a clinician and researcher at the University of Pennsylvania Health System. With researchers at the Wistar Institute in Philadelphia, Dr. Vachani is developing a blood test that may be used in distinguishing benign from malignant lung nodules. A process that involves profiling gene expression of peripheral blood lymphocytes involved in tumor immunity, the test appears, even in the early stages of development, to already have a sensitivity of 85 percent and a specificity of 87 percent in determining which lung nodules are cancerous and which are not.