Dr Elizabeth Warren, whose name has been bandied about as a possible vice-president pick for presumptive Democratic nominee Mrs Hillary Clinton, is a political star in her own right.

Dr Warren, 66, made Time Magazine's 100 Most Influential People list twice.

It was Mrs Clinton who penned her citation for the 2015 listing, noting that "she never hesitates to hold powerful people's feet to the fire: bankers, lobbyists, senior government officials and, yes, even presidential aspirants".

"She fights so hard for others to share in the American Dream because she lived it herself," Mrs Clinton added.

Dr Warren, who took her first husband's name, was the youngest of four children. She grew up in Oklahoma City, in a family situation which she has described as living on "the ragged edge of the middle class".

Her father Donald Herring first sold carpeting and fencing and later became a maintenance man. He had a heart attack when she was 12 years old, racking up huge medical bills. This forced her mother Pauline to work for the Sears company, taking catalogue orders to pay the mortgage.

Young Elizabeth, at 13, started waiting tables to contribute to the family income, but money was always tight. She would later tell The New Yorker magazine that when she fell ill, her mother would weigh how sick she was against how much the doctor's bill was going to be.

Even though she won a full university scholarship, she dropped out at 19 to marry her high school sweetheart, mathematician Jim Warren.

"It was all over at that point, statistically," she told the New Yorker. "That's pretty much it for most girls, especially back in the late 60s."

But she soon realised she had made a mistake and got back into university and then law school.

Her husband wanted her to stay home, but she wanted to work as a lawyer, so she first practised law in her living room, and later started teaching in law school. The marriage ended in 1980.

She later remarried and is still with her second husband today.

In 1995, Dr Warren joined Harvard Law School and soon became one of the country's top experts in bankruptcy and commercial law.

Around this time, her path began to cross with Mrs Clinton's.

When Mr Bill Clinton was president, Congress tried to pass a bankruptcy Bill that was supported by the credit card industry. Dr Warren lobbied Mrs Clinton at the time, who then convinced her husband not to sign the legislation.

But their alliance did not last long.

When Mrs Clinton became New York senator, where the finance industry is a major player, she voted for another version of that Bill.

Unlike Mrs Clinton who is often accused of being beholden to Wall Street, Dr Warren's entire political career has been built on protecting taxpayers and holding Wall Street accountable, making her a key player in the progressive wing of the party.

After the 2008 financial crisis, she served as the chair of the Congressional Oversight Panel for the Troubled Asset Relief Programme that allowed the government to purchase troubled assets to promote financial market stability.

She was later appointed special adviser to the Consumer Financial Protection Bureau and in 2012, became the first female Senator from Massachusetts state.

Whileties between the two women are not particularly warm, there might be some professional respect.

Before Mrs Clinton announced her bid for the presidency, she invited Dr Warren to a private meeting to seek the latter's advice on issues such as income inequality, according to the New Yorker.

Dr Warren is also extremely feisty when it comes to issues she is passionate about, and seems to be leading the charge against Mr Donald Trump, the presumptive Republican nominee and Mrs Clinton's rival.

Dr Warren tweeted in May: "I'm going to fight my heart out to make sure @realDonaldTrump's toxic stew of hatred & insecurity never reaches the White House".

Most recently she called him a "thin-skinned, racist bully", after his comments about the judge presiding over his Trump University lawsuit being biased due to his Mexican heritage.

So it is possible that a working relationship between Mrs Clinton and Dr Warren could grow out of their common disdain for Mr Trump and what he stands for.