Sen. Dianne Feinstein (D-Calif.) skipped the Democratic National Convention in Philadelphia because she was caring for her husband, who has been diagnosed with lung cancer, according to her spokesman. Richard Blum, 80, went to the doctor thinking he had pneumonia, but learned he has lung cancer, spokesman Tom Mentzer told The Times. “It was caught early, he’s receiving treatment and expects to fully recover,” Mentzer said. Blum is being treated at UC San Francisco and is responding well to the treatment, according to a source who did not want to be identified discussing the matter. Blum is a wealthy investment banker and University of California regent. When Feinstein announced earlier this week she would not attend her party's nominating convention because of a family illness, rumors swirled among California delegates that the 83-year-old senator was ill. That was put to rest when Feinstein, the ranking Democrat on the Senate Select Intelligence Committee, appeared on CNN Friday to discuss the hacking of the Democratic Party's email system. For the record: This story has been updated to clarify Blum is currently a UC Regent.