RAC1 and neoplasm: Studies have shown that the expression of RAC1 is significantly increased in some malignant tumors, including gastric cancer (Wu et al., 2014), non-small cell lung cancer (Zhou et al., 2016), breast cancer (Tian et al., 2018), etc. At the same time, its high expression is related to the degree of tumor cell differentiation, invasion and metastasis.