A variety of tumours induced by the middle T antigen of polyoma virus in a transgenic mouse family.

A transgenic mouse family expressing the middle T antigen of polyoma virus under control of the immunoglobulin heavy chain (IgE) enhancer showed the frequent occurrence of carcinomas in various organs, predominantly in females. Most frequently affected were the salivary and thyroid glands, but mammary tumours, liver haemangiomas and adenocarcinomas of unknown origin were also observed. In all tumours, the middle T antigen was found to be complexed with cellular tyrosine kinases. These results extend the range of tumour types associated with in vivo expression of middle T and with the subsequent deregulation of pp60c-src and related tyrosine kinases.