CTCF and cancer: However, despite these changes, the glandular epithelial cells maintain normal apical-basal polarity through specific subcellular expression of polarity proteins.45 Loss of cellular polarity allows cells to override normal contact inhibition signals and is thus a hallmark of cancer.44 This is consistent with the finding of Kemp et al.25 who showed that CTCF haploinsufficiency did not alter the proliferation of MEFs under subconfluent conditions but showed loss of contact inhibition at confluency.