Passage: In 2002, Kidman first appeared on the Australian rich list published annually in the Business Review Weekly with an estimated net worth of A$122 million. In the 2011 published list, Kidman's wealth was estimated at A$304 million, down from A$329 million in 2010. Kidman has raised money for, and drawn attention to, disadvantaged children around the world. In 1994, she was appointed a goodwill ambassador for UNICEF, and in 2004, she was honoured as a "Citizen of the World" by the United Nations. Kidman joined the Little Tee Campaign for breast cancer care to design T-shirts or vests to raise money to fight the disease; motivated by her mother's own battle with breast cancer in 1984.

Question: What was cause did Kidman join in 1984?
Little Tee Campaign for breast cancer care