16 
Dr. Gottesman said there was a small but measurable incidence of tumors 
when either the naked viral DNA or purified recombinant DNA containing 
two copies of the viral genome were injected into hamsters. None of the 
mice developed a viral infection after injection with EL_ coli K-12 carrying 
tiie polyoma genome. Results of the experiments in which the animals were 
fed either naked DNA or bacteria carrying the viral genome were negative. 
Dr. Gottesman said Dr. Bartels questions whether these types of tests are 
sensitive enough to predict the outcome of exposure to oncogenes. 
Dr. Gottesman said in her experience it is very difficult to design risk 
assessment experiments to ask and to answer the "right" questions. Ihe 
question always appears to be correct when the experiments are formulated; 
however, by the time the experiment is completed, time has elapsed amd there 
are new data, new information, and new questions to be addressed. 
Dr. Joklik said that Dr. Bartels is arguing that cloned oncogenes and 
retroviruses pose occupational hazards to laboratory personnel. He said 
research on oncogenes is advancing very rapidly. Information published 
several months ago may already be out of date and occasionally may be 
refuted. However, current information indicates that cell transformation 
is a highly complex, multi-step process dependent on the interaction of 
numerous genes, only a few of which have been identified. Thus, it appears 
on present evidence very unlikely that transformation is a process that is 
effected by a single gene; therefore, exposure to one single oncogene 
probably does not pose a biological hazard. He suggested oncogenes should 
be, nevertheless, handled under P2 containment conditions. He said that 
apart from HTLV he does not know of any evidence to indicate that other 
retroviruses pose any hazard to humans. 
Dr. Levine said Dr. Bartels' paper (tab 1113) poses two major questions: 
(1) can oncogenes transform cells if inadvertently inhaled, swallowed, or 
inoculated into a laboratory worker; and (2) can cloning in bacteria 
actually raise the probability that the oncogene will transform cells? He 
estimated that the risk associated with these events would be very low. 
With regard to the NIH 3T3 mouse cell assay used in these systems, he noted 
that 3T3 is a continuous cell line and, therefore, already different from 
normal cells and that some regulatory mechanism has already changed in 
these cells. He noted that Dr. Bartels raises the question of whether work 
with oncogenes constitutes an occupational hazard. However, the DNA would 
have to be inhaled, ingested, or inoculated. He noted that ingested DNA 
is unlikely to survive DNAase activity in the gut; also, the use of good 
laboratory technique should prevent inoculation. In summary, he concluded 
that Dr. Bartels has not made a case that work with oncogenes poses a real 
increased risk. He suggested that RAC might initiate a correspondence 
with Dr. Bartels to determine the types of risk assessment experiments 
Dr. Bartels saw as valuable. He said that the greatest deficiency in the 
papers is that no guidelines are put forward in terms of answering specific 
questions. 
r?ooj 
