NEW YORK (AP) _ Helen Gorman Kushnick, who helped engineer Jay Leno's rise from small-time comic to host of ``The Tonight Show,'' only to be fired as the show's executive producer four months after he replaced Johnny Carson, died Wednesday. She was 51.

Kushnick died at her home in Manhattan after a long battle with cancer, said Jane Rosenthal, a close friend.

Kushnick had been Leno's manager for years and became executive producer of ``The Tonight Show'' when he became the full-time host on May 25, 1992. The show suffered from an avalanche of criticism in its early months as ratings dipped deeper and longer than NBC executives expected.

Kushnick was fired after she was accused of demanding that guests booked by ``Tonight'' not appear on rival talk shows. Her disappointment over her dismissal lasted for years, said her longtime Los Angeles attorney Barry Langberg.

``She was hurt by it and she didn't ever stop being hurt by it, including Leno's treatment of her,'' Langberg said.

Kushnick grew up in Harlem and her first job was as secretary to producer David Gerber at 20th Century Fox in New York. She moved to Hollywood with Gerber and eventually ended up at ICM, where she rose from secretary to agent.

Upon her marriage to the late Jerrold Kushnick, she entered the management field, representing Leno, Jimmie Walker, David Letterman and others.

``She had a tough side to her, she was a negotiator, she was persistent, but she also was a very generous, loyal person,'' Langberg said.

Kushnick's role in Leno's rise to host of ``The Tonight Show'' was chronicled in the book; ``The Late Shift: Letterman, Leno and the Network Battle for the Night'' by Bill Carter.

Kushnick disagreed with Carter's interpretation and filed a $30 million libel lawsuit against Carter. She denied several assertions in Carter's book, including that she canceled acts that also were booked on Arsenio Hall's show, planted news stories in an attempt to unseat Carson, and threatened to cancel an appearance by NBC anchorman Tom Brokaw unless NBC took the 1992 Republican convention off the air.

Jerry Kushnick died of cancer seven years ago. The couple had twins and one of them, a boy, became infected with AIDS during a blood transfusion and died at age 3.

Kushnick became a pioneer in the fight against AIDS. She testified before Congress, asking them to change the rules to test the blood supply for AIDS.

Kushnick is survived by her daughter Sara Rose, and her brother, Joseph Gorman.