TCF4 and lung cancer: Additional functional analysis showed that ITF2 overexpression in lung cancer cells H23R decreased the expression of HOXD9. Taking into account the basal activation of the Wnt pathway in this cell line, we believe that an alternative regulatory mechanism affected by ITF2 is modulating the expression of HOXD9. Reinforcing this hypothesis, HOXD9 expression has been shown also to be regulated by epigenetic mechanisms such as the long noncoding RNA HOTAIR [32,33], which has been linked to cisplatin-resistance [34].