T cell lymphoma in transgenic mice expressing the human Hsp70 gene

In the course of studying the role of hsp70 in the differentiation of pancreatic β cells, transgenic founder mice were generated with the human hsp70 gene fused to the human insulin gene promoter. One resulted in a transgenic line that consistently developed diabetes mellitus, but unexpectedly three other independent transgenic founders developed generalized malignant lymphoma within 10 months after birth. Immunochemical and RT-PCR analyses revealed that the transgene was expressed in the lymphoma cells, Flow cytometric analyses revealed that the tumor was originated from T lymphocytes. Our results provide the first experimental evidence that hsp70 is involved in the tumorigenesis of T cells most likely through the blockage of apoptotic signals.