TSC2 and colorectal cancer: Carmofur, a potent ASAH1 inhibitor that has been used to treat colorectal cancer in some countries (47, 59), selectively reduced the viability of TSC2-null cells in a dose-dependent manner (Figure 5B, IC50 = 17 μM) and to a lesser extent TSC2-addback cells (IC50 = 253 μM).