Even in a time with modern medicine and advanced research techniques, cancer is a killer. In the United States, cancer is the second leading cause of death, and one of every four deaths is due to cancer1. Cancer becomes even deadlier when it spreads from its origin to other sites in the body. This is called metastasis. Cancer can metastasize to many different organs, but the lungs are one of the most common metastatic sites2. The full reasons for this are unknown, but a new study has identified one factor that contributes to the prevalence of lung metastases.