The high levels of CD98hc expression in metastatic tissues compared to primary tumors have been found in different types of solid cancers (114, 115), and CD98hc expression in primary tumors is associated with increased metastatic development in HNSCC (43, 116), breast cancer (36), and gastric cancer (117). The gene discussed is SLC3A2; the disease is head and neck squamous cell carcinoma.