USP12 and neoplasm: Moreover, decreased levels of these chemokines were only observed in the supernatants of tumour cells expressing USP12-WT but not in those of tumour cells with USP12-C48S (Fig. 3d and Supplementary Fig. 2d), a catalytically inactive USP12 mutant16; a similar phenomenon was observed in LLC tumour tissues expressing the different forms of USP12 (Supplementary Fig. 2e).