RAC1 and pancreatic neoplasm: In epidermal keratinocytes, the Rac1 activator Tiam1 has been shown to prevent keratinocyte apoptosis after growth factor starvation and heat shock treatment.20 In several experimental settings and in different cell types, Rac1 has been shown to have an important role in either pro-apoptotic or anti-apoptotic mechanisms.21, 22, 23, 24 Inhibition or deletion of Rac1 in HeLa cells and pancreatic cancer cells attenuated the DDR upon UV-irradiation or ionizing radiation, whereas the DDR was enhanced in a hepatic tumor model.25, 26, 27