The outlook for patients with breast cancer is determined in part by whether or not their tumor has spread to other sites in the body. A team of researchers, led by Roman Perez-Fernandez and colleagues, at the University of Santiago de Compostela, Spain, has now identified in a subset of patients with breast cancer, a marker associated with the occurrence of tumors at distant sites; a finding that they hope might help predict a patient's outlook more accurately.

Specifically, the team found that in patients with breast cancer that was accompanied by the presence of tumor cells in nearby lymph nodes, high levels of expression of the protein Pit-1 were associated with tumor spread to distant sites.

The authors therefore suggest that analysis of Pit-1 expression in human breast tumor samples could help predict the outlook for patients with lymph node–positive breast cancer.