In contrast to the proapoptotic effect by suppressing Src activity through the intrinsic apoptosis and Akt pathways in colorectal tumorigenesis,45 no apoptotic effects have been detected in Rack1 deficiency‐rescued MB tumor mice in this study, suggesting the distinct signaling mechanisms may be mediated by Rack1 during the tumorigenesis of MB. This evidence concerns the gene RACK1 and neoplasm.