Although the USP14/UCHL5 DUB inhibitor b-AP15 induced anti-tumor response in several types of malignant tumor including colorectal cancer, myeloma and breast cancer [8, 9, 15], its effect on human prostate cancer cells, especially the castration-resistant prostate cancers (CRPC), is undefined yet. This evidence concerns the gene ZUP1 and colorectal cancer.