Recombinant DNA Advisoiy Committee - 5/30-31/91 
that he was disappointed with the way in which human neuroblastoma cell lines reflect the 
behavior of the tumor. He said that cloning efficiencies vary widely and that different cell 
lines show different adhesion molecules and respond in a varied maimer to growth factors. 
He said the wide range of transduction efficiencies (0-14%) was a clear reflection of this fact. 
Dr. Leventhal noted that it was unclear as to how many bone marrow biopsies would be 
performed and stressed that she felt it was necessary to know the morphology on each biopsy. 
She said the procedures for bone marrow biopsy needed to be more clearly spelled out in the 
document. Dr. Walters suggested the investigators separate the consent form for the bone 
marrow transplant patients from the consent for the gene marking, and if this were done 
suggested using Dr. Deisseroth's model of a consent form. Dr. Breimer said this was 
acceptable to him and that he felt this should then be done for the AML protocol as well. 
Dr. Geiduschek asked if it was known if there was zero clonality in the multi-cell population 
which is amplified during relapse. Dr. Breimer said that the basic assumption that is being 
made is that all the cells grow equally and that having a retroviral marker will neither favor 
nor hinder subsequent growth and that all cells that are clonigenic would be marked in the 
same proportion in the patients. 
Dr. Mclvor said that he wanted to know if there were animal models for neuroblastoma that 
had been studied which looked at the issue of the range of cell doses that are necessary in 
order to generate tumor relapse. He said he felt this information should be available. 
Dr. Breimer noted that between 1,000 and 1 million human neuroblastoma cells are sufficient 
to produce tumors in SCID mice, a strain that has a severe immune deficiency. He noted that 
it was hard to interpret and said he was not convinced that this data had any relevance to 
fresh tumors since they are biologically different. 
Dr. Leventhal asked what would be done if the patient relapsed somewhere other than in the 
marrow. Dr. Breimer replied that if it wasn't clinically indicated for diagnosis that a biopsy 
would not be done simply to address the gene marking question. 
Dr. Hirano asked who would bear the cost of these treatments and said this should be stated 
clearly in the consent form. Dr. Brenner said that since St. Judes was a charitable institution 
and no patients are charged for any procedures, that this was not an issue. He noted that St. 
Judes even pays for airline tickets and hotel accommodations for the parents of the children. 
Dr. Carmen said that in the section entitled "Marrow Harvest and Marking" the term "gene" 
should be amplified by the use of the word "bacterial" to show that the marking gene is a 
"bacterial marking gene" in all cases. Dr. Brenner said he would make this change. 
It was agreed that Dr. Walters and Mr. Brewer would review the consent form at a later date 
to ensure that all the revisions had been properly made, since they had been agreed upon by 
Dr. Brenner and all that was needed was an assurance they had all been accomplished. 
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Recombinant DNA Research, Volume 14 
