Figure 8 shows that the impact of UGT1A1*28 polymorphism on increasing the plasma SN-38 concentration and side effects; neutropenia was reproduced in more than 80 of the 100 times of VCS trials with most sets of parameters except for ID 4, 5, 6, 15, 24, and 29. This evidence concerns the gene UGT1A1 and neutropenia.