The City of Hope Orange County announced on Wednesday that Diana Ross will be the headliner this year for its annual Promises of Hope gala. City of Hope is one of the largest and most advanced cancer research and treatment organizations in the United States, with a legacy of more than 100 years. Over the years, the organization has grown into a national system including a Los Angeles campus, as well as a network of clinical care locations across Southern California, and cancer treatment centers and…..