3 There was no correlation between UGT1A1*6 and UGT1A1*28 mutations and the efficacy of IRI; 4 The double wild type was more prone to grade 0–2 neutropenia, the single-site variant was more prone to grade 0–2 diarrhea, and the double-site variant was more prone to grade 3–4 neutropenia, but none of them were related to leukopenia. This evidence concerns the gene UGT1A1 and Decreased total leukocyte count.