Ovarian cancer is responsible for nearly 15,000 deaths annually in the United States and is the fifth leading cause of death from cancer among women. Due to its relatively asymptomatic nature, the majority of ovarian cancer patients present with advanced-stage disease. Although this disease is relatively responsive to chemotherapy as compared to other types of cancer, most ovarian cancer patients who initially respond to chemotherapy eventually relapse and their disease is resistant to further treatment of this disease. Increased understanding of chemotherapeutic drug sensitivity/resistance mechanisms is important for the design of new therapeutic strategies. Dr. Johnson’s approach to understanding the resistance problem is to find the patterns of gene expression within tumor cells that are responsible for the drug resistance phenotype. He will use a technique that measures the expression of thousands of genes simultaneously in a panel of human ovarian cancer cell lines that are either drug sensitive or resistant. Genes identified will be tested for their ability to confer drug sensitivity or resistance. Findings should lead to new targets in ovarian cancer treatment.