To validate the specificity of an in-house developed IHC assay as well as to validate the correlation between SLFN11 and the response to different DDA and DDRi, SLFN11 knockout (KO) cells were generated in DU145 prostate cancer cells using CRISPR/Cas9 (Supplementary Fig. S1D; Supplementary Fig. S1E, F confirm the KO by western blotting and immunofluorescence, respectively). This evidence concerns the gene SLFN11 and prostate cancer.