While the first mutant (USP48 C98S) contained a single cysteine to serine exchange at position 98 within the catalytic domain, the second mutant tested was a short isoform of USP48 (USP48-S1) missing the C-terminal region of the protein that was shown to lack deubiquitinating activity and the expression of which was found to be upregulated in several types of cancer cells compared to normal tissues23, 24. This evidence concerns the gene USP48 and cancer.