SUN1 and breast neoplasm: Moreover, cDNA from several human breast tumor cell lines contained less SUN1, SUN2, nesprin-2 mRNA, and lamin A/C than cDNA from MCF10A, an immortalized but nontumorigenic mammary epithelial cell line widely used as a normal control; a notable exception to this pattern was nesprin-2 expression in ZR75-30 cells (Fig.5B).