NTP May Test Cell Phones

journal Toxicologic Pathology, are highly valued by other researchers in the field. In 1997, as part of its twentieth-anniversary celebration, the journal recognized a 1984 article by Haseman and coauthors James Huff and Gary Boorman, "Use of Historical Control Data in Carcinogenicity Studies in Rodents," as one of the 10 most frequently cited articles in the journal's n history. Recently, Haseman and colleagues have been refining the use of trans-genic animals developed at the NIEHS for carcino-genicity studies. One of the benefits of these animals is that they evidence chemical-related carcinogenic effects more quickly than the strains used in the standard rodent bioassay. Using transgenic animals dramatically shortens the time frame required for completing the studies and reduces the number of animals that must be used. Transgenic mouse studies typically last only 6 months and usually use only 15-20 animals per group, compared with 2 years and 50-60 animals per group for the standard rodent bioassay. However, the unique characteristics of the transgenic animal have also required new statistical methodologies. For instance, for some transgenic lines, the main tumor of interest is the skin papilloma, which can be observed directly rather than requiring a necropsy. A multiplicity of these skin papillomas can occur within the same animal over time. The appeal of transgenics. Transgenic mouse require only one-third the number of animals, com In a standard rodent bioassay, the end point of analysis would be whether or not the animal developed a tumor, but for a transgenic mouse model, the end point of analysis is how many tumors the animal has and over what time period they develop. To accurately evaluate this response, Haseman and colleague David Dunson have developed new mathematical models that take into account both tumor multi-plicity and the time course of tumor occurrence. Haseman is frequently called upon to represent d the institute in evaluations of new testing methods such as the Frog Embryo Teratogenesis Assay-Xenopus, 9'Qfn or FETAX. Haseman takes pride in offering an unbi-ased analysis. "The developers of these tests want them adopted, sometimes very badly," he says. "I see it as my job to make certain that the statistical methodology utilized in these new models is appropriate and that the data are correctly evaluated and interpreted." Although eligible to retire after more than 30 years of government service , Haseman is in no hurry. 'I really enjoy my job, and the people at …