User blog comment:McGillicuddy/Luzifer in Season 10 ?/@comment-26067572-20150411143334

Rowena said that the Mark is just a curse, "the first curse" but she could be removed, like any other curse. And with the Mark, her magic seems to be inefficient against Dean, making him an important threat to her, and she thinks that Dean is a Man of Letter, so she would have good reasons to remove the Mark.

However, the Mark was made by Lucifer, the second most powerful archangel (the first one being Michael), and I don't think that removing the Mark is so easy. So yeah, maybe the only way to get rid of the Mark, is by God's help or Lucifer's help, however, I don't think that God is going to intervene. Even if Lucifer is released, he's definitely not going to help Sam and Dean, they sent him back to the cage a second time the last time he was free. However, if they are desperate, they could set him free, but to open the cage, they need the rings of the four Hoursemen and I don't think that Death is going to help them to set free Lucifer a second time.