In support of a role for Rac inhibition in chemosensitization, Rac1 knockdown has been shown to sensitize lapatinib resistance [88], and a small molecule inhibitor of Rac1, NSC23766, was shown to increase sensitivity to the anti-HER2 therapeutic trastuzumab [33], overcome gefitinib resistance in non-small cell lung carcinoma [89], and be effective in combination therapy with eroltinib, another tyrosine kinase inhibitor [90]. This evidence concerns the gene RAC1 and non-small cell lung carcinoma.