Among the 22 selected DNA helicase genes, the expression of SLFN11 has been previously shown to be correlated with homologous recombination efficiency and drug sensitivity to PARP inhibitor in non-small-cell lung cancer [11–13], while no correlation was detected between SLFN11 expression and HRD score in breast cancer by this study. This evidence concerns the gene SLFN11 and breast cancer.