In contrast, another study in a different teratocarcinoma, Tera-1, found that a HERV LTR co-opted to regulate the PRODH gene exhibited an enhancer effect in responsive to Sox2 and not NF-κB (Suntsova et al., 2013), suggesting that NF-κB activation alone might not greatly alter HERV expression. Here, SOX2 is linked to teratocarcinoma.