RAC1 and cancer: Accumulating evidences have shown that Tiam1 expression plays a role in cancer progression and metastasis by activating Rho-like GTPases and Tiam1-Rac1 pathway in various cancers, such as nasopharyngeal carcinoma [7], breast cancer [8], colorectal cancer [9], retinoblastoma [10], hepatocellular carcinoma [11] and Ras-induced skin tumors [12].