A source close to Wasserstein said the 55-year-old single mother was diagnosed with leukemia and has not been able to receive chemotherapy because of an infection, the New York Daily News reported.
"There's a percentage chance of survival," the source said, "and our hope is that she can fight this off. But it's very serious."
Wasserstein won a 1989 Pulitzer Prize and Tony Award for "The Heidi Chronicles."
Her eighth play to be staged in New York is "Third," starring Dianne Wiest.
Boston schools pull out free condoms over wrapping complaints
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