Marcus was last seen in the Hull area during the morning of February 23 and was reported missing to police later that day when he failed to return home.
Concern is increasing for Marcus who, although missing from Hull is known to have family and friends in the Grimsby area and it is possible he may have travelled to that location.
Marcus is described as 6ft tall of slim build with a pale complexion and collar length, blond hair. When last seen he was wearing a grey tracksuit with a hoodie and black trainers.
Marcus or anyone knowing his whereabouts is asked to call 101 quoting log number 636 of 23 February 2016.