User: Given a reference text about Mikel Artetxe Guezuraga, tell me when he turned professional and what his biggest wins are.
Assistant: Mikel Artetxe Guezuraga turned professional in 1999 and had the biggest wins of his career in 2006 with a stage win in the Vuelta a Asturias and the sprints classification in the Troféu Joaquim Agostinho.