RAC1 and neoplasm: Overexpression of the Src tyrosine protein kinase gene, Src64B, activates JNK signalling and leads to cell death in the eye-antennal epithelium, but when bskDN is coexpressed, tumour overgrowth occurs, in a mechanism involving upregulation of the actin-cytoskeletal regulators, Rac1 and Dia, as well as Ras signalling, which inhibit the Hippo pathway, thereby promoting tumour growth [79].