The Galveston County Daily News, March 29, 2007 By Heber Taylor GALVESTON - Who is responsible when a drug that has been approved for medical treatment later proves to cause cancer? Is it the drug industry? The scientists who do the research? Federal regulators? Or the doctor who prescribed the medicine to a patient, based on information from a variety of sources, including a pitch from a sales representative of the drug companies? That was one of the interesting questions that came up at a public forum Tuesday on the influence of the drug industry. The industry spends billions marketing its products to doctors. It spends vast sums to fund research at medical schools, such as The University of Texas Medical Branch.