The incidence and mortality of cancer are high in China, but the diagnosis and treatment of malignant tumors represented by breast cancer and lung cancer are facing great challenges. Oxidative stress refers to a pathological process in which the redox state in cells is destroyed due to the production of active substances or the limited compensatory capacity of REDOX system. Studies have shown that oxidative stress is often unbalanced with the level of oxidative stress in tumors and is closely related to the occurrence and development of malignant tumors. Glutathione (GSH) is abnormally expressed in lung cancer, colorectal cancer and other tumors and is associated with oxidative stress imbalance. In addition, glutamate cysteine ligase (GCL) and its subunits, a key enzyme involved in the synthesis of GSH, have also attracted great attention, which may be an important cause of GSH synthesis disorder and oxidative stress imbalance in malignant tumors, and play a role in promoting or inhibiting cancer in different tumors. However, the relationship between GCL and its subunits and tumor development and clinicopathological features of patients has not been systematically described. Therefore, this paper reviews the expression and significance of GCL and its subunits in tumors.