Estrogens and the genetic control of tumor growth.

Biochemical and genetic studies of the estrogen-induced pituitary tumors of the F344 rat provide a new model for understanding cancer biology. Because a genetic difference in tumor susceptibly already exists in this animal model it is possible to search for the underlying mechanisms. Interestingly, thus far marked changes in expression of known or unknown oncogenes do not appear to be involved in the formation of this tumor. Similarly, known angiogenic factors have not been implicated in this model's dramatic angiogenic response to estrogen. It will be very informative to dissect out the critical genes and the products that are involved in this system and then to determine whether similar genes are involved in human, estrogen-induced cancers.