As previously noted, JJ012 is reported to have a consistent chromosome 9 monosomy, and this is significant given that a number of important tumour suppressor genes occupy this locus, including INK4A/ARF [28], PTCH1 [29], and the more recently described RECK gene which is downregulated in many common cancers [30,31]. Here, PTCH1 is linked to neoplasm.