BRCA1 associated protein 1 (BAP1) is a tumour suppressor that is believed to mediate its effects through chromatin modulation, transcriptional regulation, and possibly via the ubiquitin-proteasome system and the DNA damage response pathway (Murali et al. 2013). BAP1 mediates the deubiquitination of Host cell factor 1 (HCFC1) thereby regulating cell growth (Eletr & Wilinson 2011), though deubiquitination of HCFC1 does not lead to increased HCFC1 stability. HCFC1 is K48 and K63 ubiquitinated; the major site of linkage are lysines 1807 and 1808 (Machida et al. 2009).