Sen. Charles Grassley, the ranking Republican on the Senate Finance Committee, is pressuring the University of Texas M.D. Anderson Cancer Center to account for its charitable-care practices as part of his ongoing crackdown on tax-exempt hospitals. Responding to pointed questions about everything from the hospital's relationships with insurance companies to bill-collection policies to fundraising activity, M.D. Anderson officials this week delivered four bound volumes of data to Grassley. The Iowa senator has been investigating tax-exempt organizations, including hospitals he says don't provide public benefits equal to the subsidies they receive.