title: An ETP model (exclusion-tolerance-progression) for multi drug resistance.
abstract: BACKGROUND
  It is known that sensitivity or resistance of tumor cells to a given chemotherapeutic agent is an acquired characteristic(s), depending on the heterogeneity of the tumor mass subjected to the treatment. The clinical success of a chemotherapeutic regimen depends on the ratio of sensitive to resistant cell populations.
  
  
  RESULTS
  Based on findings from clinical and experimental studies, a unifying model is proposed to delineate the potential mechanism by which tumor cells progress towards multi drug resistance, resulting in failure of chemotherapy.
  
  
  CONCLUSIONS
  It is suggested that the evolution of multi drug resistance is a developmentally orchestrated event. Identifying stage-specific time windows during this process would help to identify valid therapeutic targets for the effective elimination of malignancy.
authors.affiliation: Division of Gastroenterology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. sukannan@utmb.edu
authors.forename: Subburaj
authors.initials: S
authors.lastname: Kannan
mesh_terms: D000818:Animals; D018450:Disease Progression; D018432:Drug Resistance, Multiple; D004361:Drug Tolerance; D006801:Humans; D008954:Models, Biological; D009369:Neoplasms / Q000473:pathology*