With Eric Dane the latest cast member to depart, John Byrne looks back on previous Grey's Anatomy stars who - for one reason or another - are no longer part of the Seattle Grace furniture.

Although it hasn't seen as many cast changes as its medical mega-star predecessor ER, Grey's Anatomy lost yet another regular following last Friday's announcement that Eric Dane was quitting his role as Dr Mark 'McSteamy' Sloan ahead of the show's ninth season.

A lot of the departures have been clouded in controversy - here are the six key ones during the show's sensationally successful eight seasons:

Katherine Heigl (Izzie Stevens)

When she left After spending much of season six working elsewhere, things came to a head when Heigl reportedly failed to show up for Grey's Anatomy on March 11th, 2010. She had apparently come to an agreement with Shonda Rhimes to release her from her contract with immediate effect. Her character had left Seattle after surviving cancer.

Why she left Heigl said that her departure was not about advancing her film career - which was moving along very nicely at the time - but that she wanted to focus more on her family.

How she's doing In January 2012, Heigl stated in an interview that she has asked the producers of Grey's Anatomy if she could return to the show to wrap up Izzie's storyine: "I've told them I want to," she said. "I want to see that girl take some power back." In her personal life, she and husband, inger Josh Kelley, adopted a second child in April 2012.

TR Knight (George O'Malley)

The rest is here:
Grey's Anatomy Ex Files