title: Immunostimulation and immunoinhibition of premalignant lesions.
abstract: BACKGROUND
  The immune reaction may be either stimulatory or inhibitory to tumor growth, depending upon the local ratio of immune reactants to tumor cells.
  
  
  OBJECTIVE
  A tumor-stimulatory immune response may be essential for survival of a neoplasm in vivo and for the biological progression from a premalignant lesion to a malignancy. Neither a positive nor a negative correlation between the magnitude of an immune-cell infiltrate and a cancer's prognosis can reveal whether the infiltrate was stimulating or inhibiting to the tumor's growth unless the position on the nonlinear curve that relates tumor growth to the magnitude of the immune reaction is known.
  
  
  CONCLUSIONS
  This hypothesis is discussed in relation to the development of human malignant melanomas and colorectal cancers.
authors.affiliation: Department of Pathology, University of Washington, Seattle, WA 98118, USA. prehn@u.washington.edu
authors.forename: Richmond T
authors.initials: RT
authors.lastname: Prehn
mesh_terms: D000818:Animals; D015179:Colorectal Neoplasms / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance; D007114:Immunization; D008545:Melanoma / Q000276:immunology*; D051379:Mice; D010212:Papilloma / Q000276:immunology*; D011230:Precancerous Conditions / Q000276:immunology*; D012878:Skin Neoplasms / Q000276:immunology*