The future growth of the iconic Mayo Clinic in Minnesota depends largely on the state's answer to Rochester's request for a half a billion dollars in infrastructure improvements, Dr. John Noseworthy, the clinic's president and CEO, said Tuesday. "We're never going to leave Minnesota, and we don't want to leave Minnesota," he said in an interview at the National Press Club, where he made a pitch for federal investment in health care and medical research. "But we've got to decide where we're going to put the next $3 billion" in projected Mayo expansion. "If they say yes, that's great, we want to stay in Minnesota," he added. "If they say no, or you're going to have to go for a bonding bill every year for the next 30 years, we'll have to rethink about whether that's the best use of our money." Noseworthy, a neurologist, emphasized that the Mayo is not threatening to leave Rochester, where the clinic was established 149 years ago. But in a clear message to the Legislature, where the clinic's proposal has encountered significant sticker shock, he said "there are 49 states that would like us to invest in them. That's the truth."