We first showed that CTCF can repress cell growth and colony formation suggesting a tumour suppressor function for CTCF.15 In addition, CTCF expression also confers a protective effect against apoptosis in various cell lines.16, 17 CTCF has been shown to modulate the expression of various cancer-associated gene loci including notable examples: CMYC,18IGF2,19TP53,20TERT21 and INK4/ARF. The gene discussed is CDKN2A; the disease is cancer.