Cancer becomes more deadly when the malignancy travels, ormetastasizes, to other tissues.

Scientists seeking to develop mice that mimic this trait havefound they can reproduce patients' metastases by transplantingintact tumor tissue from people into immunodeficient mice.

Articles in the current issue of Cancer Research and theInternational Journal of Cancer, by scientists from the school ofmedicine at Keio University in Tokyo and the laboratory ofcancer biology at the University of California, San Diego,describe this new way to more reliably replicate humandisease.

Co-author Robert Hoffman, a professor of pediatrics at UCSDand president of the privately held biotechnology companyAntiCancer Inc., told BioWorld that previous models of cancerin mice, using suspensions of human cancer cells injected intothe appropriate organ, lack tissue architecture and do not showas much correspondence with the disease in the patient.

"People may not have really understood the importance oftissue architecture in preserving all the qualities of the tumor,"he said.

The researchers transplanted human stomach tumors in so-called "nude" mice that have no thymus and cannot producetransplant-rejecting T cells. All 23 transplants from patientswith regional lymph node metastases reproduced thisdevelopment in the mice.

Also, 18 of 26 transplants from patients with liver metastases-- 69 percent -- reproduced this distant metastasis in the mice,data in the Cancer Research article show.

Meanwhile, the International Journal of Cancer article indicatesthat in 15 transplants from patients without liver metastasis,only one mouse had the cancer spread to the liver.

AntiCancer developed the microsurgical techniques used in thestudies, while the Tokyo scientists provided access to a seriesof patients whose cancer could be correlated with the mousemodel.

The San Diego company calls the model "MetaMouse," and hasdeveloped versions for cancers of the colon, pancreas, breast,prostate, lung, bladder, stomach, ovaries, head and neck.

The models are used to evaluate diagnostics and drugstargeting the tumor or its spread, Hoffman said. The mice alsoprovide a long-term source of tumor tissue that can be grownin quantity for a sort of "precision tumor catalog." Patientscould possibly have their tumors transplanted through such asystem to test therapeutic strategies, and laboratories mightuse the models in basic research.

Hoffman said there are 17 articles in press or alreadypublished about the MetaMouse, which was first described injournal articles in 1991.

-- Nancy Garcia Associate Editor

(c) 1997 American Health Consultants. All rights reserved.

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