Haggag et al. have reported a specific Ran guanine nucleotide exchange factor inhibitory peptide (RAN-IP, its sequence is CAQPEGQVQFK) which could block the interaction between Ran and Ran guanine nucleotide exchange factor in MDA-MB-231 breast cancer cells to inhibit RanGTP formation (Haggag et al., 2019). This evidence concerns the gene RAN and breast cancer.