To further substantiate these findings, GRHL2 (WT) or SUMOylation-deficient GRHL2 mutants were stably expressed in GRHL2-negative MDA-MB-231 breast cancer cells by means of retroviral gene transfer, and expression of GRHL2 and selected GRHL2 target genes CD24 and E-cadherin (CDH1) then was analyzed by Western blot and quantitative real-time PCR (qRT-PCR) analysis. Here, CD24 is linked to breast cancer.