a_2-巨球蛋白(a_2M)是机体内广谱的蛋白水解酶抑制剂,既可清除体内蛋白水解酶,又可抑制自由基产生。虽然电离辐射后a_2M变化各家报道不一,但a_2M的抗辐射损伤功能在人及动物实验中均已被证实。肿瘤细胞多缺乏a_2M受体,也不能合成分泌a_2M,而a_2M具有抗肿瘤生长及转移的性质。推测a_2M在肿瘤治疗时,与放疗等的联合,具有积极的意义。 A_2-macroglobulin (a_2M) is a broad-spectrum proteolytic enzyme inhibitor in the body. It can both eliminate proteolytic enzymes in vivo and inhibit free radical production. Although a2M changes after ionizing radiation have been reported differently, a2M’s anti-radiation damage function has been confirmed in human and animal experiments. Tumor cells often lack a2M receptors and can not synthesize and secrete a2M, while a2M has anti-tumor growth and metastasis properties. It is inferred that the combination of a_2M and radiotherapy during the treatment of cancer has positive significance.