In metastatic breast cancer, prognosis and treatment is largely influenced by estrogen receptor (ER) expression of the metastases. However, little is known about ER expression across metastases throughout the body and surrounding normal tissue. Using a positron emission tomography (PET) tracer, researchers in the Netherlands have been able to identify differences in ER expression, which could help guide treatment for metastatic breast cancer patients. The study is featured in The Journal of Nuclear Medicine‘s August issue. {read more here}