[ RadSafe ] AW: So called bystander effect for brain tumors in irradiated mice

[Rainer.Facius at dlr.de]

Dear Bobby, 

thank you for your comments which I second and the copy of the Camphausen et al. (2003) paper. I am satisfied to note the reasons why Camphausen et al. deliberately refrain from using the term 'bystander effect' for their (intriguing) observations. For the same reasons I think Mancuso's usage of the term is compounding and hence obfuscating the issues - at least as far as mechanisms are concerned. 

All the best and kind regards, Rainer

Camphausen K, Moses M A, Me´nard C, Sproull M, Beecken W-D, Folkman J, O'Reilly M S.
Radiation Abscopal Antitumor Effect Is Mediated through p53.
Cancer Research 63(2003)1990-1993.


________________________________

Von: Scott, Bobby [mailto:BScott at lrri.org]
Gesendet: Do 21.08.2008 03:30
An: Facius, Rainer
Betreff: FW: So called bystander effect for brain tumors in irradiated mice

________________________________


From: Scott, Bobby 
Sent: Wednesday, August 20, 2008 7:30 PM
To: 'cjb01 at health.state.ny.us'; 'GRMarshall at philotechnics.com'; 'HOWARD.LONG at comcast.net'; 'matzkin at invap.com.ar'
Subject: So called bystander effect for brain tumors in irradiated mice

 

To: Clayton Bradt, Glenn Marshall, Howard Long, and Rainer Facius

 

Dear Colleagues:

 

In light of your interest in the so-called bystander effect that was discussed in Radsafe Digest (Volume 160, Issue 3, August 20, 2008) that relates to brain tumors in radiosensitive mice, I thought you may find the attached paper by Camphausen et al. (2003) to be of interest.  The paper is entitled "Radiation abscopal antitumor effect is mediated through p53." Please note the terminology "abscopal effect" as mentioned by Rainer Facius is used as has been done historically. The terminology bystander effect is more recent and has usually referred to un-hit cells in the vicinity of hit cells that are also affected. With the study design indicated for the mouse study of brain tumors, one has to consider the dose scattering.  One cannot have a bystander effect if there is a small scattered dose irradiating the brain as apparently was the case for the PNAS paper by Mancuso et al. (2008).  An abscopal effect can occur in un-irradiated tissue and can be either detrimental or beneficial (see the attached paper for an example of a benefit).  A 3 Gy dose to a large portion of the body can suppress the immune system possibly allowing for a small scattered dose (e.g., few mGy) to induce cancers at other sites in radiosensitive mice that would otherwise not occur after a small dose alone. 

 

Best wishes,

Bobby R. Scott

Senior Scientist

Lovelace Respiratory Research Institute

2425 Ridgecrest Drive SE

Albuquerque, NM 87108 USA