What caused the death of the movie star John Wayne?

Although he enrolled in a cancer vaccine study in an attempt to ward off the disease, Wayne died of stomach cancer at the age of 72 on June 11, 1979, at the UCLA Medical Center, and was buried in the Pacific View Memorial Park cemetery in Corona del Mar, Newport Beach. According to his son Patrick and his grandson Matthew Muñoz, a priest in the California Diocese of Orange, he converted to Roman Catholicism shortly before his death.He requested that his tombstone read "Feo, Fuerte y Formal", a Spanish epitaph Wayne described as meaning "ugly, strong, and dignified".The grave, which went unmarked for 20 years, is now marked with a quotation from his controversial 1971 Playboy interview: "Tomorrow is the most important thing in life. Comes into us at midnight very clean. It's perfect when it arrives and it puts itself in our hands. It hopes we've learned something from yesterday."