The miR-34 isoforms, predominantly mir-34a, have tumor suppressor functions in multiple cancer types, which is sometimes attributed to their p53 status44, 45, though the mechanisms of chromosomal deletion or epigenetic silencing are also major contributors26, 27, 28, 29, and miR-34 expression is prognostic for patient outcome or relapse45, 46, 47, 48. The gene discussed is TP53; the disease is cancer.