RAC1 and melanoma: While the role of RAC1 in BRAFi resistance is evident, the role of RHOA, RHOC, and their downstream effector Rho-kinase (ROCK) is less clear with conflicting evidence as to whether ROCK inhibition promotes or inhibits MAPKi in melanoma, and our recent study showed that, in contrast to RAC1 knockdown, which sensitized A375 cells to vemurafenib treatment, knockdown of either RHOA or CDC42 had no such effect (16, 18, 19, 50).