ALCAM and osteosarcoma: At present, CAR-T therapies that specifically targeting different kinds of solid tumor associated antigens have been studied in the treatment of osteosarcoma, and the tumor associated antigens mentioned above included human epidermal growth factor receptor 2 (HER2) [9, 10], activated leukocyte adhesion molecules (ALCAM, CD166) [11], GD2 [12], and interleukin IL-11 receptor alpha (IL-11Rα) [13].