TNF and melanoma: Further studies found that Rac1 is a key proapoptotic modulator in a variety of cell types in response to different apoptotic stimuli, including UV-induced apoptosis in Rat-2 fibroblasts [21], β-adrenergic receptor-modulated apoptosis in rat ventricular myocytes [22], growth factor deprivation-induced apoptosis in human hepatoma cells [23], capsaicin-induced apoptosis in human breast epithelial cells [24], TNF-α-induced apoptosis in intestinal epithelial cells ([25], hyperglycemia-induced apoptosis in cardiomyocytes [26], and Taxol-induced apoptosis in human melanoma cells [27].