PHILADELPHIA - Comedian Bill Cosby has resigned from the board of trustees of Temple University, his alma mater said in a statement on Monday, after the entertainer was hit with a wave of sexual assault accusations.More than a dozen women have come forward in the past few weeks with accusations that Cosby, 77, sexually assaulted them as far back as the 1960s.Patrick O'Connor, chairman of the Philadelphia university's board of trustees, said Cosby called him on Monday to resign."He didn't want his personal issue to detract from his service to Temple," O'Connor said in a phone interview. "He was a great trustee. I thanked him for his service."Cosby has never been charged, and his lawyers have said the assault claims were discredited and defamatory.Cosby was proud of his education at Temple, where he discovered a gift for comedy that led to a successful career in stand-up and groundbreaking roles for an African-American actor in the television series such as "I Spy" and "The Cosby Show."The decision to leave Temple's board comes two weeks after NBC and Netflix canceled planned projects with Cosby as more women came forward with stories of assault. Promoters have canceled some of the dates on his US stand-up comedy tour.Temple's silence on the situation since the allegations came to light had raised uncomfortable questions for some students at the university.