CTCF and neoplasm: Mutants L309P, R377H and R339W abrogated the tumour suppressive effect of CTCF and exhibited cellular proliferation similar to the empty vector control (all p < 0.0001 compared to WT), whilst R339Q had an intermediate effect on CTCF’s anti-proliferative function (p < 0.0001 compared to WT; p < 0.001 compared to control, Fig. 2D).