Emmy-winning actor Catherine O'Hara died from a blood clot in her lungs as a result of rectal cancer, according to her death certificate. Her official cause of death was listed as a "pulmonary embolism" due to an underlying cause of cancer, sources confirmed to NBC Los Angeles on Monday. O'Hara's Los Angeles County death certificate also showed that she was cremated, The Associated Press reported . The oncologist who signed off on the certificate indicated that he had been treating O’Hara since