Prolifix Ltd., of Cambridge, U.K., focused on the discovery and development of small-molecule drugs that modulate the cell cycle, said it has identified a new mechanism by which normal breast cells become tumorigenic. The finding relates to the mechanism of action of the cell cycle control protein cyclin D1, a cancer-promoting protein. Levels of cyclin D1 are frequently increased in tumor cells, and it endows them with the capacity for continual growth.

Prolifix collaborator Rene Bernards, of the Netherlands Cancer Institute, has identified a novel mechanism through which cyclin D1 stimulates breast cancer cell growth by controlling the activity of the estrogen receptor. The company believes that, since the estrogen receptor is already known to be central to the development of breast cancer, this finding provides insight into the processes that govern tumor progression. Prolifix has exclusive rights to the research, published in the Nov. 15 issue of Genes and Development. -- Nuala Moran