IJCEP Copyright © 2007-All rights reserved.
Int J Clin Exp Pathol 2(3),286-299;2009

Original Article
The Laboratory Opossum (Monodelphis domestica) as a Natural Mammalian Model for
Human Cancer Research

Zhiqiang Wang, Gene B. Hubbard, Fred J. Clubb, Jr. and John L. VandeBerg

Department of Pathology, The Methodist Hospital, Houston, Texas, 77030; Department of Genetics, Southwest Foundation for Biomedical
Research, San Antonio, TX 78227; Department of Comparative Medicine, Southwest Foundation for Biomedical Research, San Antonio, TX
78227; Texas Heart Institute, Houston, TX 77030

Received 08 October 2008; Accepted in revision 13 October 2008; Available online 06 November 2008

Abstract: This study established that human cancer cells (A375 melanoma, HT-29 colon cancer, PC-3p prostate cancer) that were xenografted
into suckling opossums could proliferate and globally metastasize as early as 11 days after injection. Light and electron microscopic
examinations (HT-29 colon cancer) determined that the cellular features exhibited by the xenogeneic human tumors grown in laboratory
opossums were consistent with those observed in tumors removed from humans. The tumor induction rate, patterns of tumor growth and
regression, and types of host immune responses against the xenografted tumors were influenced by injection dosages, injection sites and
injection ages of suckling opossums. The results highlight the value of the opossum model as a natural in vivo system for investigating human
cancer growth, metastasis and apoptosis at the cellular and molecular levels; enhancing identification of tumor associated antigens or T cell
epitopes through use of humoral and cellular expression cloning techniques; elucidating mechanisms utilized by tumor cells to evade host
immunosurveillance; and devising diagnostic and therapeutic methods for cancer treatment.   (IJCEP810004).

Key Words: Animal model, human cancer, Opossum, Monodelphis domestica

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Address all correspondence to: Zhiqiang Wang, MD, PhD, Department of Pathology, The Methodist Hospital, Houston, Texas, 77030
Telephone: (713) 441-3490, Fax: (713) 793-1630, E-mail:
zwang@ tmhs.org