Notably, one double-strand break (DSB) caused by one gRNA in NANOG1-knockout prostate cancer cells led to the same length deletion in both alleles in the establishment of knockout cell lines using the CRISPR/Cas9 system, and two DSBs caused by two gRNAs in NANOGP8-knockout cells led to different length deletions on each allele. This evidence concerns the gene NANOGP8 and prostate carcinoma.