TGM2 and breast carcinoma: However, the comparison of brain metastatic breast cancer cell line MDA-MB-231-BR and metastatic breast cancer cell line MDA-MB-231 without organ selectivity revealed that the mRNA and protein levels of TG2 were both downregulated dramatically in MDA-MB-231-BR compared with MDA-MB-231 (Dun et al., 2015).