IGF2 and esophageal cancer: In cancer stem cells, loss of imprinting of the paternally expressed IGF2 transcript, colocalized in the same gene cluster and imprinted in the opposite manner from H19 [33], has been similarly linked to resistance to 5-FU, oxaliplatin, and radiotherapy [34]; however, loss of IGF2 imprinting has also been associated with improved survival of patients with esophageal cancer [26].