Cao Zheng (July 9, 1966 - February 21, 2013) was a noted Chinese-American mezzo-soprano opera singer who appeared regularly with the San Francisco Opera and on stages worldwide. Born during China's Cultural Revolution, she came to the United States at the age of 23 with two suitcases and $45 to her name. She took up opera at the Curtis Institute of Music in Philadelphia. She then moved to San Francisco to start her singing career, first as an Adler Fellow and then in repeated performances at the Opera beginning with a 1995 appearance as Siebel in Gounod's "Faust." Her signature performance was playing Suzuki, the patient servant in Puccini's "Madama Butterfly". She also performed roles in Mozart's "Idomeneo," "The Rake's Progress" by Stravinsky and Virgil Thomson's "The Mother of Us All."

Ms. Cao's biggest assignment was in "Bonesetter," in which she created the role of Ruth Young Kamen, the American-born protagonist torn between her Chinese roots and the demands of a new life. It was a triumphant performance, marked by tonal heft and emotional vulnerability.

It was shortly after that opera that Ms. Cao was first diagnosed with cancer, which was already in stage four. The tumours had spread to her liver, lung, neck and spine, and she was given six months to live.

But through a bold series of treatments, she survived three more years, continuing to sing and make public appearances. She premiered Nathaniel Stookey's song cycle "Into the Bright Lights" with the Philharmonia Baroque Orchestra, substituting for von Stade, who had written the libretto based on her own experience at the end of a career.

Beloved by many people, Ms. Cao died on February 21, 2013 at her home in San Francisco after a long battle with cancer. She was 46.