RAC1 and head and neck squamous cell carcinoma: Consistently, in both TCGA pan-cancers and HNSCC datasets, RAC1-amp and RAC1-gain tumors displayed a 1.7-fold and a 1.2-fold increase in RAC1 mRNA expression compared to diploidy tumors (Figure 1D, Supplementary Figure S1A,D), while RAC1-loss tumors have reduced intra-tumoral mRNA expression, implicating likely major roles of somatic copy number alterations in governing RAC1 mRNA expression in human cancers.