YAOUNDE (Reuters) -Announcing his bid for an eighth term in July, Paul Biya, Cameroon's 92-year-old president, said he was heeding "numerous and insistent" calls to stay in office, but this year's election cycle has also featured striking appeals for him to step aside. First came Catholic Archbishop Samuel Kleda, who went on French radio last Christmas to say it was "not realistic" for Biya to keep doing the job. Then came the defections of not one but two cabinet members from Cameroon's vote-rich northern regions, both of whom openly challenged Biya's fitness to lead.