Pharmacogenomics studies genetic variations and drug metabolism to match the best drug for phenotype (in specific diseases) before beginning therapy. Matching effective drugs to DNA-based diagnostic and predictive markers is expected to be at the forefront of treatment. Examples of tests and collaborating drug and diagnostic test companies include diagnostic tests; genetic markers and drug targets for schizophrenia, hematochromatosis, peripheral arterial occlusive disease, rheumatoid arthritis, severe anxiety, stroke, progression of advanced heart disease, obesity, and diabetes; and markers for colon, breast, and ovarian cancer.