CD44 and cancer: Their findings indicate that CD44 variant exons v8-v10 in gastrointestinal cancer (or CD44v9-containing isoforms in other types of cancers) interact with and stabilize the cystine transporter xCT, preventing it from being internalized and degraded as well as enhancing its capacity for downstream GSH synthesis and defense against ROS (Figure 8; Ishimoto et al., 2011).