ASAH1 and cancer: The typical dose of 20‐40 mg/day results in serum concentrations of 96‐200 ng/mL (0.25‐0.5 μM).16 Tissue accumulation, both for normal tissue and cancer tissue, is approximately 10‐fold higher than serum levels, suggesting that clinically relevant concentrations are between 2.5 and 5 μM.17, 18 Because tamoxifen was reported to exert an off‐target effect on ASAH1, we evaluated its activity on PGCC progeny and found that colony formation in PGCC derived from PPC1 was strongly inhibited at 5 μM tamoxifen with an efficacy similar to LCL521 (Figure 3A,B).