title: Blood transfusion promotes cancer progression: a critical role for aged erythrocytes.
abstract: BACKGROUND
  In cancer patients, allogeneic blood transfusion is associated with poorer prognosis, but the independent effect of the transfusion is controversial. Moreover, mediating mechanisms underlying the alleged cancer-promoting effects of blood transfusion are unknown, including the involvement of donors' leukocytes, erythrocytes, and soluble factors.
  
  
  METHODS
  Two syngeneic tumor models were used in Fischer 344 rats, the MADB106 mammary adenocarcinoma and the CRNK-16 leukemia. Outcomes included host ability to clear circulating cancer cells, and host survival rates. The independent impact of blood transfusion was assessed, and potential deleterious characteristics of the transfusion were studied, including blood storage duration; the role of erythrocytes, leukocyte, and soluble factors; and the kinetics of the effects.
  
  
  RESULTS
  Blood transfusion was found to be an independent and significant risk factor for cancer progression in both models, causing up to a fourfold increase in lung tumor retention and doubling mortality rates. Blood storage time was the critical determinant of these deleterious effects, regardless of whether the transfused blood was allogeneic or autogenic. Surprisingly, aged erythrocytes (9 days and older), rather than leukocytes or soluble factors, mediated the effects, which occurred in both operated and nonoperated animals. The effects of erythrocytes transfusion in the MADB106 model emerged immediately and dissipated within 24 h.
  
  
  CONCLUSIONS
  In rats, transfusion of fresh blood is less harmful than transfusion of stored blood in the context of progressing malignancies. Further studies should address mediating mechanisms through which erythrocytes' storage duration can impact the rate of complications while treating malignant diseases and potentially other pathologies.
authors.affiliation: Neuroimmunology Research Unit, Department of Psychology, Tel Aviv University, Israel.
authors.forename: Shir
authors.initials: S
authors.lastname: Atzil
authors.forename: Michal
authors.initials: M
authors.lastname: Arad
authors.forename: Ariella
authors.initials: A
authors.lastname: Glasner
authors.forename: Noa
authors.initials: N
authors.lastname: Abiri
authors.forename: Roi
authors.initials: R
authors.lastname: Avraham
authors.forename: Keren
authors.initials: K
authors.lastname: Greenfeld
authors.forename: Ella
authors.initials: E
authors.lastname: Rosenne
authors.forename: Benzion
authors.initials: B
authors.lastname: Beilin
authors.forename: Shamgar
authors.initials: S
authors.lastname: Ben-Eliyahu
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000556:secondary / Q000628:therapy; D000818:Animals; D045744:Cell Line, Tumor; D018450:Disease Progression; D004905:Erythrocyte Aging / Q000502:physiology*; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D004912:Erythrocytes / Q000473:pathology / Q000502:physiology*; D005260:Female; D007942:Leukemia, Experimental / Q000097:blood / Q000473:pathology / Q000628:therapy; D008175:Lung Neoplasms / Q000097:blood / Q000556:secondary / Q000628:therapy; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000097:blood / Q000556:secondary / Q000628:therapy; D009369:Neoplasms / Q000097:blood / Q000473:pathology; D051381:Rats; D011916:Rats, Inbred F344; D017208:Rats, Wistar