Reduced expression of either Crk or CrkL, by RNA interference-mediated gene knockdown, inhibited cell adhesion, migration, invasion, proliferation, and in vivo tumor growth of many cancer cell lines such as GBM (31, 32), breast cancer (11, 12, 13), gastric cancer (17, 33), cervical cancer (34), ovarian cancer (22, 23, 35), prostate cancer (36, 37), bladder cancer (26), oral squamous cell carcinoma (25), synovial sarcoma (38), rhabdomyosarcoma (27), hepatocellular carcinoma (39), and head and neck squamous cell carcinoma (40) cells. Here, CRK is linked to breast cancer.