Rep. Tom Lantos, the chairman of the House Foreign Affairs Committee and the only Holocaust survivor to serve in Congress, has died, spokeswoman Lynne Weill said Monday. Lantos, 80, a Democrat, disclosed last month that he had been diagnosed with cancer of the esophagus. He said at the time that he would serve out his 14th term but would not seek re-election in his northern California district, which includes part of San Francisco. The timing of the diagnosis was a particular blow because Lantos had assumed his committee chairmanship just a year earlier, when Democrats retook control of Congress. He said then that in a sense his whole life had been a preparation for the job.