Aureon Laboratories Inc., a Yonkers-based laboratory that specializes in cancer treatment, said that Robert Shovlin has been promoted from president to president and chief executive officer. Vijay Aggarwal will step down as CEO, but will remain a member of the company’s board of directors. Shovlin joined the company in June 2005 as vice president of sales and marketing. He was promoted to chief operating officer in 2007.