Next, we examined the role of PAK2 in HNC cell proliferation by depleting PAK2 in three HNC cancer cell lines with shRNA against PAK2 (shPAK2) or against eGFP (shControl) (Fig. 2a, e, and Supplementary Figure S2b) and observed significantly reduced viability in PAK2-depleted cells (Fig. 2b, f, and Supplementary Figure S2c). This evidence concerns the gene PAK2 and cancer.