NAIP and cancer: Nonetheless, the activity of this LTR promoter in testis, and previous description of the MER21C LTR promoter active in a leukemic cell line [21], coupled with reports of elevated NAIP expression in myelodysplastic syndromes and leukemia [35,36], provides an enticing model to study potential upregulation of these LTR promoters in certain forms of cancer, possibly through hypomethylation, since both LTRs are CpG-rich (unpublished data).