We identified four loci possibly associated with gemcitabine-induced leukopenia/neutropenia [rs11141915 in DAPK1 on chromosome 9q21, combined P=1.27×10, odds ratio (OR)=4.10; rs1901440 on chromosome 2q12, combined P=3.11×10, OR=34.00; rs12046844 in PDE4B on chromosome 1p31, combined P=4.56×10, OR=4.13; rs11719165 on chromosome 3q29, combined P=5.98×10, OR=2.60].