SELENOS and cancer: Deletion of the Trsp gene completely eliminates selenoprotein expression (Carlson et al., 2018) and was shown to increase oxidative stress and increase reactive oxygen species (ROS) accumulation in macrophages or the liver of mice with cancer (Serrão et al., 2018), while excision of Trsp in mammary glands led to increased mammary tumors and decreased survival (Serrão et al., 2018).