The characterization of a newly identified, highly metastatic variety of Dunning R 3327 rat prostatic adenocarcinoma system: the MAT LyLu tumor.

The Dunning R 3327 AT tumor is a rapidly growing, androgen insensitive, serially transplantable rat tumor of prostatic origin. In early passages, the AT tumor had a very low rate of distant metastases (less than 1 per cent); however, after 60 serial subcutaneous passages, the AT tumor has given rise to a new tumor line which has an extremely high metastatic rate. Greater then 75 per cent of all animals inoculated with this late passage tumor develop lymph node metastases alone or in combination with lung metastases. This high passage tumor seems to be distinct from the original AT tumor since it has a substantially faster doubling time and a massively increased metastatic potential; it has therefore been named the Dunning R 3327 MAT LyLu tumor (metastatic AT tumor able to disseminate to lymph nodes and lung). The MAT LyLu tumor, like the parent nonmetastatic AT tumor, is androgen insensitive with regard to its growth rate, rate of distant metastases and mean survival time. This newly characterized MAT LyLu tumor provides an appropriate animal model system for testing the potential effectiveness of a variety of therapeutic approaches specifically aimed at limiting the metastatic spread of prostatic cancer.