Barack Obama's grandmother, Madelyn Dunham, has died of cancer on the eve of the US presidential election. She was a central figure in the early life of the Democratic candidate.

Barack Obama's grandmother, Madelyn Dunham, has died of cancer on the eve of the US presidential election. She was a central figure in the early life of the Democratic candidate.

Obama's childhood was largely spent in the care of his grandparents.

Dunham and her late husband Stanley raised the young Barack in Hawaii for many years while his mother, who had remarried, lived abroad.

Known within the family as "Toot", a shortened form of the Hawaiian word "tutu", meaning grandmother, she gave him a stable home and the traditional American values brought from her own Midwestern childhood.

She was also a trailblazer in her own right, having risen from a lowly position to be one of the first women vice-presidents of the Bank of Hawaii.

In a major speech on race he gave in March, Obama described her as "a woman who helped raise me, a woman who sacrificed again and again for me, a woman who loves me as much as she loves anything in this world".

She was also the "white grandmother", he said, whom he could no more disown than he could his controversial African-American pastor, the Reverend Jeremiah Wright.

"She was the cornerstone of our family, and a woman of extraordinary accomplishment, strength and humility," said Obama.

This was despite her being "a woman who once confessed her fear of black men who passed her by on the street, and who on more than one occasion has uttered racial or ethnic stereotypes that made me cringe".

On the campaign trail he made references to how the 86-year-old had instilled in him her belief in hard work, accountability and self-reliance.

Dunham was living in Honolulu, with Obama's sister, Maya Soetero-Ng, until she lost her battle with cancer on Monday.

In a joint statement announcing her death, Obama and his sister said: "She was the cornerstone of our family, and a woman of extraordinary accomplishment, strength and humility. She was the person who encouraged and allowed us to take chances."

The news came 10 days after Obama broke off campaigning in order to pay a last visit to Dunham in Hawaii.

Born Madelyn Payne in 1922, the daughter of a Midwest oil company clerk, she was raised in Kansas and attended college at the University of Washington.

In 1940 she married Stanley Dunham, described by Obama as something of a rebel and during World War II worked as an aircraft inspector for Boeing. She later studied at the University of California in Berkeley.

The couple moved to Honolulu in about 1960 with their daughter Stanley Ann. Still in her teens, Ann would soon meet Obama's father - Barack Hussein Obama senior, a student from Kenya at the University of Hawaii, fall pregnant and marry him.

After the marriage failed, Dunham and her husband helped raise their grandson, making financial sacrifices to send him to a better school.

In his autobiography, Dreams from My Father, Obama describes his grandmother as "suspicious of overwrought sentiments or overblown claims, content with common sense".

She was someone who "taught me values straight from the Kansas heartland", he said in a campaign advertisement this year.

Dunham largely shunned the media spotlight turned on the family by Obama's emergence on to the national stage, granting few interviews.

But speaking to David Mendell of the Honolulu Advertiser newspaper for his book on Obama, From Promise to Power, she talked of trying to instil her own work ethic in her grandson.

"I'll admit that I did give him a few kicks in the pants," she told Mendell. "Not many, but a few."

Following his mother's death aged 52 from cancer in 1995, Obama was left all the more reliant on Dunham for support from that side of his family.

Announcing that Obama was to break off his general election campaign for two days in October to visit his grandmother, aide Robert Gibbs said she had "always been one of the most important people in his life". - BBC Online