A Christian school in Greenfield is closing its doors at the end of the school year because of financial stresses. Principal Joe Ollis said the 24-year-old Cornerstone Christian School almost closed last year. He told The Recorder that it has become increasingly difficult for the school to cover its expenses, which total around $200,000 annually. Parents were told last fall that annual tuition would rise from about $4,250 to $5,500, an increase he said most were unable or unwilling to pay. The school currently has more than 50 students in prekindergarten through the eighth grade. It is affiliated with Greenfield Alliance Church.