▽The New England Journal of Medicine: Research & Review Articles on Diseases & Clinical Practice ●05/06 08:07 ContentEditorialApr 30, 2025Science behind the StudyVariation in EPO and ErythrocytosisM.F. McMullinThe author describes the scientific foundations and implications of a study on variant EPO and erythrocytosis.Original Article Identification of Hepatic-like EPO as a Cause of PolycythemiaApr 26, 2025Cholelithiasis, Cholecystitis, and CholedocholithiasisZ.-L. Tu and J.-F. TuAn 80-year-old