DLL4 and cancer: Although the underlying cause of DLL4 dysregulation in LFS or other cancer cell lines and tissues may not be fully known, our results suggest that 1) the presence of a germline TP53 mutation or 2) the prevalence of epigenetic conditions or 3) even the contribution of a gene-disruption by translocation, whose presence may be interfering with the normal function of the immune system, may be partially or wholly responsible for the subsequent development of tumorigenesis.