LBR and cancer: The NE in human cancer cell lines (HeLa S3 and U2OS) and human normal diploid fibroblasts (IMR90) contains two types of subdomains readily distinguished by their structural differences2: one is a pore-rich region enriched in B-type lamin and the INM protein lamin B receptor (LBR), whereas the other is a pore-free island enriched in A-type lamin and the INM protein emerin.