Old Disease in a Young Mouse: Case Report for Lymphocytic Leukemia in an 11-Week-Old Female SCID/Beige Mouse

The SCID (Prkdcscid) Beige (Lystbg) (Fox Chase SCID Beige) strain is an inbred and severely immune deficient mouse model that is commonly used for tumor biology and xeno graft research. The SCID mutation results in defective antibody responses due to improper maturation and function of B cells and T cells. Furthermore, the SCID mutation impairs DNA double-strand break repairing mechanisms. The beige mutation further diminishes the animal’s immune system by causing defective Natural Killer (NK) cells. Altogether, these mutations induce susceptibility to diseases such as cancers. Although there are reports of spontaneous hematopoietic cancers developing in immune deficient mice, this phenomenon is typically seen in advanced age mice. In this report, we discuss a unique case of a spontaneous lymphoma developing in a female SCID/Beige mouse at 11 weeks old. This rare occurrence emphasizes the importance of distinguishing spontaneously arising diseases from xeno grafted tissues when interpreting studies.