Gwen Chambers is a cancer patient. She meets Kristina at Kristina's first doctors about discussing the tumor. When she meets Kristina she's in remission. Gwen offers support and love to Kristina in this incredibly tough time and is Kristina's touchstone. The two grow incredibly close and create an unbreakable bond.
Kristina goes to say goodbye to her chemoteam and learns that Gwen's cancer is back.
In season five, episode twenty-one, Kristina recieves a phone call from Gwen's sister telling her that she should go see Gwen. Kristina visits and updates Gwen on everything, but Gwen can't respond. Later in the episode it is revealed that Gwen has passed away. Later, Kristina gets a package from Gwen that her sister sent. It has an oak tree sapling, a check to help start the school, and a card that reads, "it's going to be a great school, enjoy the ride! love Gwen.".
Kristina takes it very hard and feels guilty that she survived cancer and Gwen didn't. She names the charter school after Gwen.