Retired Brig. Gen. John Groff, who joined the Marines before World War I, has died, officials said Thursday. He was 100.

Groff died Tuesday while waiting for a medical checkup in Oceanside, ending a running battle with cancer that had lasted some 30 years, a Marine spokesman at Camp Pendleton said.He was the senior member of the Marines' retired general list.

Groff was a leatherneck for much of the first half of the 20th century. He enlisted in 1912 and first saw combat in 1914 when American troops landed in Veracruz, Mexico, during the Mexican Revolution.