RACK1 and cancer: Moreover, Rack1 negatively regulates the invasiveness and metastasis of cancer cells in gastric cancer [32, 34]; On the contrary, Rack1 promotes invasion and metastasis of prostate cancer and hepatocellular carcinoma cells [61, 62]; Consistently, knockdown of Rack1 reduces invasion in melanoma, oral squamous carcinoma cells, and lung cancer cells [35, 36, 38, 63].