title: The paradoxical effects of splenectomy on tumor growth.
abstract: BACKGROUND
  There is a vast and contradictory literature concerning the effect of the spleen and particularly of splenectomy on tumor growth. Sometimes splenectomy seems to inhibit tumor growth, but in other cases it seems, paradoxically, to facilitate both oncogenesis and the growth of established tumors.
  
  
  METHODS
  In this essay I have selected from this large literature a few papers that seem particularly instructive, in the hope of extracting some understanding of the rules governing this paradoxical behavior.
  
  
  CONCLUSIONS
  In general, whether splenectomy enhances or inhibits tumor growth seems to depend primarily upon the ratio of spleen to tumor. Small proportions of spleen cells usually stimulate tumor growth, in which case splenectomy is inhibitory. Larger proportions of the same cells, especially if they are from immunized animals, usually inhibit tumor growth, in which case splenectomy results in tumor stimulation.
authors.affiliation: Department of Pathology, University of Washington, Seattle, WA, USA. prehn@u.washington.edu
authors.forename: Richmond T
authors.initials: RT
authors.lastname: Prehn
mesh_terms: D000818:Animals; D002455:Cell Division; D004195:Disease Models, Animal; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation / Q000473:pathology; D009369:Neoplasms / Q000276:immunology / Q000473:pathology* / Q000628:therapy*; D013156:Splenectomy; D013934:Thymectomy