Just read that Mrs McKluskey (played by Kathryn Joosten) has died in real life from cancer and had been suffering with it while she was filming the last season of the show. So so so sad to hear. 
Loved her character. They really kept that a secret that she was ill. Rest in Peace.
'Desperate Housewives' Star Kathryn Joosten Dies at 72
Actress Kathryn Joosten, best known as "Desperate Housewives'" most meddlesome neighbor Karen McKluskey, died Friday after a long battle with lung cancer. She was 72.
http://www.huffingtonpost.com/2012/06/02/kathryn-joosten-desperate-housewives-dead_n_1565040.html
Actress Kathryn Joosten, best known as "Desperate Housewives'" most meddlesome neighbor Karen McKluskey, died Friday after a long battle with lung cancer. She was 72.
Joosten's death came less than three weeks after the emotional "Desperate Housewives" series finale, which saw the redemption and eventual death of Mrs. McKluskey as well.
Joosten won two Emmys for Outstanding Guest Actress in a Comedy Series for her "Desperate" role, in 2005 and 2008, and was nominated for a third time in 2010.
Prior to her residence on Wisteria Lane, Joosten had another tony TV address: The White House. She played Mrs. Landingham, President Bartlet's (Martin Sheen) secretary on "The West Wing" for the series' first two seasons until her character died in a car accident.
She also had memorable TV roles on "Scrubs," "Joan of Arcadia," "My Name Is Earl," "General Hospital" and "Dharma & Greg."
Joosten was first diagnosed with lung cancer in 2001. The cancer returned in September 2009. After Joosten underwent surgery and chemotherapy treatments, she was officially declared cancer-free in January 2010. She was an advocate for lung cancer awareness and research, even doing speaking engagements about her battle.