In subgroup of patients receiving GP regimen (Fig. 1E), rs4253212 (χ2 test P = 4.92 × 10−5; OR = 3.31, 95%CI:1.26–8.72, P = 0.015) in ERCC6 was significantly associated with neutropenia. This evidence concerns the gene ERCC6 and Decreased total neutrophil count.