Scientists at Stanford University are studying an alternative to biopsy. And it may someday help diagnose cancers far more easily and effectively. The research involves using a special machine to analyze a drop of blood or a microscopic piece of tissue to find cancer-related proteins. Just by watching how a protein changes, scientists say they can figure out if a patient is responding to treatment. So far -- they've had success identifying cancers of the blood in lab mice and even a small number of human patients.